Guide to Universe Sandbox (2.1.4)

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This is a guide to using Universe Sandbox. If you see any errors and/or typos, feel free to tell me so I can fix it. There is no complete manual at the moment, so I wrote this. I started when Universe Sandbox was still version 2.1.3; not much has changed since, but I'll have to redo several images, so it might take a while. Posting it before another 5 updates come out and I'll update it ASAP.
The images are in links and not [/img]'d because that causes page to load slow and the images are larger than screen if I post them.
It's spread out over several posts because I want to be able to add to the guide and the 20,000 character limit.
Btw the random numbers (1.1, 1.2, etc) are so you can "Ctrl-F" and skip quickly to that section.

Edit: the image links are broken because the site i used to host images has shuffled them all.

Currently Version 2.1.4

Table of Contents

Interface 1.1
Controls 1.2
Keys 1.3


Interface 1.1

This is your Interface, say hello

http://i.imgdiode.com/3NHrFp.png

To the right of the screen is the Object editing bar, where you can change a celestial body's size, weight, and more. I'll call it the (Object Editing) bar.

On the left side, is all the Simulation Options settings, these will change how your simulation looks and works. I'll call this the (Simulation Settings) bar.

On the top-left corner of the screen is the bar where you can control gravity and time. I'll call this the (Time/Gravity panel).

There are 3 panels at the bottom of the screen.

The one on the left controls all camera and view options. (View panel)

The middle one changes the mode of the simulation (Mode panel)

The one on the right controls and manipulates bodies, including adding new bodies. (Body Manipulation bar)

Controls 1.2

In this section a summary of each option, knob, slider, check-box, drop-down box, and/or anything other option will displayed along with any tips and tricks. At the bottom of each will be a screenshot if appropriate (For example, there won't be a screenshot for accuracy mode; you can't show that.)

Simulation Settings bar.

http://i.imgdiode.com/KT64fA.png

On very the top, is the Collision mode settings. The option on the left is labeled “Bounce”. It causes bodies to bounce when the intersect, or collide with each other. The option on the right, “Collide”, causes intersecting bodies to merge into a larger one.

Below is the accuracy mode setting. On the left is RK4 and on the right is Euler.
Universe Sandbox can use both RK4 and Euler math to calculate the position of objects as they are moved by gravitational forces. RK4 stands for Runge-Kutta.

Rk4:
More accurate
Slower

Euler:
Faster
Less accurate
Inaccurate especially in highly eccentric orbits.

Note that at high time-steps, Euler becomes more accurate, so if you run a simulation a faster than it is normally stable at, use Euler.

X Dust, X Trails, and X Impacts simply remove all dust, trails, and impacts.
Ctrl-D is the shortcut key to remove dust,

The "Shadows on Rings" option lets rings have shadows. Checking this option will cost you CPU power. The simulation may slow down depending on how many rings and shadows you have. This option is nearly identical to the Shadows & Lights on Dust option. However this option only puts shadows on rings, and not other dust particles

http://i.imgdiode.com/U4W1bh.png

Checking or Unchecking the box next to Label will turn on of off the names or labels of celestial bodies. This can also be toggled on and off by pressing the "L" key.

http://i.imgdiode.com/YkeqlO.png

Again, Checking or Unchecking the box next to Trails will turn on of off the trails of celestial bodies. This can also be toggled on and off by pressing the "T" key.

http://i.imgdiode.com/zEl4Nv.png

Some of the following values in this bar are a special kind of box. You can click and type in a number, click to open a sidebar and click a preset number, or click on the arrow keys to move the number up and down. I'll just call this a value-box for simplicity, because the point of it is to enter a valid value. Note that the longer you hold down the arrow keys, the faster the value goes up, and vice versa.

The next box, Auto length for trail segments. This will automatically adjust how long the trails are so that they do not lag the simulation excessively.

Alternatively, you can set this value yourself, with the min segments value-box, where you enter a number to select the number of segments the trail must be.

I'm not sure of how long a segment is, or how it is determined, but after some experimentation, it appears that a segment is as long as 2 time steps. For example, a object traveling at 1 km/day, timestep at 1 day, and min segment length at 20 would have a trail of 40 km.

Show bodies at actual size is a helpful setting, as it lets you see even the tiniest of objects easily. When you un-check the bar, the setting will be turned on and the slider activated. Slide it to the right and objects will be come larger and more similarly sized (proportionally). Slide it to the left and the reverse will be true. When you check the box, objects return to their actual size. As long as you have the box un-checked, you should be able to see even the tinest of objects no matter where your slider is.

In order to locate tiny objects without using this slider, objects should be labeled. Then, toggling the L key will let you see them. In addition, the Highlight option, which we will discuss next, can also be used in a similar fashion.

http://i.imgdiode.com/Rv65aM.png

The Highlight check-box, turns on or off highlights. The highlights are basically just circles around the bodies that enable you to see them far away. When the planet, comet, moon, star, or celestial body becomes smaller than the highlight, the highlight stays at it's constant size. This can be helpful when dealing with large and small scale orbits or bodies in a single simulation. Pressing the key "H" toggles highlights on and off.

http://i.imgdiode.com/KX8XJe.png

The next check-box is the Relations Line check-box. When activated, there will be lines connecting gravitational parents to their "children". This lets you see the gravitational parent of a body. For example, the moon's gravitational parent is the Earth, and the Earth's gravitational parent is the Sun. An alternative way to toggle these lines is the ";" key.

http://i.imgdiode.com/YvGugk.png

The Projected Paths Option shows the future path of any object. It is often highly inaccurate due to other objects and/or bodies which interfere. Projected Paths shows the path an object will take if all other objects on the simulation are frozen or locked in position.

http://i.imgdiode.com/O96Dj7.png

A Hill Sphere is the area around a celestial body where that celestial body is capable of retaining a satellite in orbit. Simply, if you're within a body's Hill Sphere, you'll stay there. If you're not in their Hill Sphere, you'll be drawn to a more massive body. You might notice that the most massive body in the simulation has no Hill Sphere. This is because nothing else is massive enough to drag a body away from it! (Note that i use the word massive and not large because gravity depends on mass and not size.)
The Hill Sphere option allows you to see where you can safely place a body in orbit and not have it fly away to another body. However, because of time-step, it is generally a good idea to place a body well within the Hill Sphere to avoid it flying away.

http://i.imgdiode.com/X5xoom.png

A Lagrange point is a point where you can remain stationary relative to 2 more massive bodies. If you want the exact explanation and definition, Wikipedia has an excellent article on this. The points L1, L2, and L3 are not very stable. L4 and L5 are the best choices to place an object at, should you wish to simulate this. Also, make sure that the body at L4 or L5 does not exceed more than 10% of the mass of the smaller gravitational body (there are 2 larger bodies, remember? This is the smaller of the two). If you do, the orbit will slowly but surely deteriorate. Checking this box will display the 5 lagrange points of all bodies on the screen, so if you happen to have a lot of bodies, this may lag somewhat.

http://i.imgdiode.com/irayrw.png

The Constellation check-box is used solely in the "Constellations in Galaxy" or the "Constellations" simulation. Checking and unchecking this box will turn on and off the constellation lines in the simulation. You can try to recognize the constellations with and without the lines.

http://i.imgdiode.com/fBjtxY.png

There are two sub-check-boxes next to the Constellation check-box.
Label toggles the names of the constellations
Lines toggle the lines of the constellations
Note that when either of these are checked, the main Constellation check-box will automatically check itself.

http://i.imgdiode.com/Y9zjg7.png
http://i.imgdiode.com/tWdD6N.png

In addition, directly under the Constellation check-box is a drop-down box. When you have Lines enabled, the drop down box will selectively show constellations. For example, if you click on "Zodiac". Only Zodiac constellations will be connected with lines. The last option in the drop-down box, "Common" works differently. A constellation is only connected with lines when common is selected if it belongs to all the other groups. That is if it is a Western, Ptolemy, and Zodiac constellation.

http://i.imgdiode.com/aeDZT0.png

The new lighting system check-box and slider can be used to make planets and stars look differently. The new lighting system has blending while the old lighting system had only completely dark and completely light. The slider can change how bright or dim the light should be. I recommend leaving this at default which is new lighting system at 0.050.

http://i.imgdiode.com/zKlnRx.png

The Phantom Sun check-box is used when there is no light source in the simulation. A star, like the sun, or Rigel would be considered a light source. When Phantom Sun is checked, there will be an invisible light source that lights up your celestial bodies. The light source will not affect your bodies in any other way.

http://i.imgdiode.com/PI5Q1F.png

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Shadows & Light check-box is used to let dust have light and shadows too. This can lag if you have a large amount of dust.

http://i.imgdiode.com/U4W1bh.png

Create Collision Lights will make temporary light sources when there is a collision. After experimentation, it appears that the larger the bodies colliding, the more light. Don't expect to light up our entire solar system by colliding 2 dice.

http://i.imgdiode.com/DGC1b7.png

The Grid option is used to create a grid. The grid is several circles and squares that lie on the xy-plane. Curiously, the first circle in the grid in the Solar system simulation happens to be close with mercury. The second aligns to Venus, the third to Earth, Jupiter, Saturn and so on. If you use grid in the Earth and Moon simulation, the first circle is almost identical to the moon's orbit around Earth.

http://i.imgdiode.com/aoCAfl.png

Background on or off will turn the background from completely black to another background of your choice. Leaving the background check-box unchecked will give you a black background, and when the check-box is checked you are able to select a background of your choice from the drop-down box. The choices are Stars, Milky Way, Microwave, and White. As amusing as it sounds, no, Microwave is not a picture of your kitchen microwave. It is a map of the background radiation left over from the Big Bang 14.6 billion or so years ago. For normal simulations, i don't suggest using Microwave or White. It is pretty strange for outer space to look all white. However white can be useful when you want to make diagrams without any stars interfering.

The brightness slider directly underneath the background drop-down box controls the brightness of the background. I prefer to keep this minimal when running a simulation. It can also get annoying in videos if you have the background turned up too high. I suggest keep this at or below default especially if you're making a video.

The Orient check-box to the right of the background drop-down box will Orient the stars, Milky Way, or Microwave background to our Solar System.

http://i.imgdiode.com/Twy2ct.png

The Glow check-box makes the background glow. If you just can't get enough brightness on the background for whatever reason, check the glow box.

Show fps will show your fps in the Time/Gravity panel.

3d check-box turns anaglyph 3d on. You need 3d glasses to see properly in this mode. Ctrl-C is a quick shortcut for this.

The first check-box in the "Advanced Options" section is the Multiple Processors option. I'm not sure if this is quite working yet, but it should be completed in the next update. Supposedly it works on dust but not objects yet.

The next option, Create Dust, may seem a little confusing at first. The check-box really means, create dust at collision. When two objects collide, dust will be created. Below that is the accurate check-box. It's just a RK4 version for dust. Follow the guidelines i wrote about it in accuracy section up there.

The Fade Out option makes dust from collisions eventually disappear. If you're doing a simulation with collisions and dust, it's very useful in keeping the lag down.

Dust multiplier determines how much dust is created. There is a slider that lets you set a value from 0 to 25. This is useful for reducing or increasing the dust seen in galaxies, rings, and collisions. Depending on how much dust you have in a simulation, you should turn this up or down. A simulation with multiple galaxies may lag even with x1 dust multiplier while a single small ring won't lag even with x3. If you want to film a galaxy collision, turn the time-step down to around 20,000 years and the crank the dust multiplier up to x25.

The X button to the right of the Create Dust check-box will delete all dust on the screen. Alternatively, use Ctrl-D

http://i.imgdiode.com/IsqfPZ.png

The last option in the Simulation Settings bar involves collisions. The Create Impact Marks option will let collisions create a white mark wherever a body hits another.

The X Impact button deletes all impacts

It is nice to have impact marks on, however, there is a bug where Impact Marks will cause your screen to turn into a white whirlpool of doom. If this happens, turn off impact marks and delete all current impact marks

http://i.imgdiode.com/yWS2Zg.png

Body Manipulation bar

The Body Manipulation bar is split into 3 tabs. Main Properties, Physical Properties, and Dynamic Properties. You'll notice that i have 2 different pictures of the Main Properties and Physical Properties bar. This is because stars have additional options over normal orbiting bodies, and orbiting planets have some options that stars don't.

Main Properties:
http://i.imgdiode.com/ERcS8u.png
http://i.imgdiode.com/xlz4Mq.png
Physical Properties:
http://i.imgdiode.com/6izSXK.png
http://i.imgdiode.com/4j9lFE.png
Dynamic Properties:
http://i.imgdiode.com/wHH3LL.png

Main Properties

The Name text-box is where you can enter a name for your celestial body. This name is the name that shows up on the Label when you toggle "L".

The mass value-box is used to increase or decrease mass. Presets are 1 Sun, 1 Jupiter, 1 Earth, 1 Moon, and 1kg.

The diam value-box stands for Diameter and controls the diameter of the object. Presets are Black Hole, 1 Sun, 1 Jupiter, 1 Earth, 1 Moon, 1 Asteroid.

The den value-box stands for Density and controls the density of the object. Presets are Water, Earth, and Sun.

Note: Because each an every asteroid is a different size and asteroids can vary vastly in size, the asteroid preset in the Diameter value-box is most likely just an average asteroid.

You'll notice 3 padlock-shaped buttons directly to the right of these 3 value-boxes. One must and will be locked at all times. This is because Density, depends on Mass and Diameter (technically volume). To change one variable, another one must also change. If you want to decrease the diameter, either the mass must also decrease, or the body must become more dense. When you lock a value-box, that will be the one that stays the same. In the above example, locking the Mass box would cause the density to increase.

The temp text-box shows the temperature of a planet or orbiting satellite. This text-box will only appear if you have the Planet temp checkbox checked in the Physical Properties.

A double arrow the the right of the text-box opens a panel with two sliders; albedo and infrared emissivity. This panel is identical to the one in the Physical Properties tab.

Albedo is the "reflecting power of a surface". It's usually expressed as a percentage or a decimal. A perfectly white surface, (reflects every single color in the sun's spectrum) would have an albedo of 1 or 100%, while a perfectly black surface, absorbing the colors of a sun's spectrum, would have an albedo of 0 or 0%. The slider in the Planet Temp panel lets you adjust the albedo from 0 to 1. From 0.0 to 0.1, you may enter or "slide" up to 3 decimals, or 1/10th of a percent. From 0.1 onwards to 1.0, you may only enter up to 2 decimals, a precision of 1%. Turning up the albedo will cool a planet; turning down the albedo will heat a planet.

Infrared Emissivity is the "relative ability of a surface to emit energy by radiation". Imagine looking into a deep cave. Although the cave seems very dark, it is emitting infrared energy. If i understand this right, the light energy is converted to the full spectrum on infrared energy, heating the cave, air, and/or planet. Infrared Emissivity goes from 0.0 to 1.0, it's slider works the same way as the albedo slider works. Turning up the Infrared Emissivity will heat a planet; turning down the Infrared Emissivity will cool a planet.

In Total vel value-box, which stands for Total Velocity, you can change the speed you are traveling at.

The temperature value-box does not do much. You can change it, but nothing will be affected, including habitable zones. K stands for kelvin.

The luminosity value-box affects the brightness of a star. This also determines the habitable zone, strangely. The value entered it the number of times as bright as the sun. For example, a star with 5L brightness would be 5 times as bright as the sun.

The next box, orbit, shows you the celestial body you are orbiting. This is purely and informational box and cannot be changed without renaming the body that you, or rather the said celestial body, are orbiting.

To the right of this box is a button labeled "Auto Orbit" An extremely useful button, this helps keep your fictional solar system in 1 piece by forcing the body into orbit. To make the whole simulation auto orbit, simply press the "A" key. Beware that Auto orbit often causes objects to lose their inclination though.

The Semi-major axis is the farthest a satellite reaches from its gravitational parent during its orbit. To the right of the value box is is ± sign. The number that comes after this is how much the value can vary. For example, Semi-major axis of 10 million kilometers and a ±200,000 means that the semi-major axis can vary from 9.8 million kilometers to 10.2 kilometers.

The eccentricity value-box sets the eccentricity of a body's orbit. For example, a circle would have an eccentricity value of 0 while a line would have a eccentricity value of 1.  

The inclination value-box sets the inclination of a body's orbit. Inclination is how tilted the orbital plane of an orbiting body is. A planet orbiting completely vertically over our solar system would have an inclination of 90 degrees. Pluto, however, has an inclination of 17.1 degrees. Our own planet, Earth, has an inclination of about 0.002 degrees, a negligable amount.

I can't explain the next three options:
 
Argument of Periapsis
Longitude of the Ascending Node
Mean anomaly at Epoch

i can't explain this without sounding like gibberish so i'll let this picture do the talking. If anyone can explain this better i'd be glad to add it on here.

http://upload.wikimedia.org/wikipedia/commons/e/eb/Orbit1.svg

Notice the image does not show the Mean anomaly at Epoch. The Epoch is simply the position of a body along its elliptical orbit.

The Orb Per value-box is the Orbital Period of an object, or how long an object takes to complete a single orbit. Increasing this or decreasing this changes the value of the semi-major axis, or sma.

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On the top-left of the last section, Actions, is the sub-panel “explosions”. When an object is exploded, it is split into a number of balls that move apart at a set speed. You can also use "Y" to shoot a photon torpedo that explodes everything it hits. A useful way to use explosions could be to set the velocity at zero and see how the reacts to gravitational stress (make sure the collision mode is on bounce). During large explosions, many objects , impact marks, and dust will be created, causing lag. To keep this down, you can turn the dust multiplier down, or even all the way to zero. In addition, hide trails, and disable impacts.

http://i.imgdiode.com/wVb132.png
http://i.imgdiode.com/Vvvdat.png

Directly below that panel is the delete panel. There are 3 ways to delete an object. You can select it and press the delete key, you can select it and use the delete button in the subpanel, or you can turn it into dust. Turning objects into dust can also be a helpful way to add dust to rings. If you want the object turned into dust to look anything like it was before, the dust multiplier needs to be quite high. At x20 the object should look reasonably solid. If you have a good enough computer, turning that up to x25 might be better.

http://i.imgdiode.com/eSw3Xk.png
http://i.imgdiode.com/XlJN5I.png

To the right of the Explosion panel is a Light Pulse button. This sense a ring of photons, which resemble dust in almost every way, outwards at an inclination of 0 degrees and at the speed of light. Depending on how large the simulation is, it is a good idea to speed up or slow down in order to see the light pulse. In the solar system, around 10 seconds per real second is fine. You can use black holes to suck light particles but I believe this is not fully implemented yet.

http://i.imgdiode.com/c5Evha.png

To the right of the Light Pulse button is a Black Hole button. This button sets the selected object's size and density so that it becomes a black hole.

As of right now, black holes act extremely funny. They aren't really black holes yet. To ensure a black hole is able to capture light, you must make it massive enough. Even the densest bowling ball won't be able to capture light while a massive but non-black hole star can. This is because Universe Sandbox assumes all the mass of a body is on a single point, not spread out like a star.

The mass you need to turn an object into a “black hole” or something that can capture light, is determined by the density of the object.
An object with a density of 3702499400437110000000000000000000000000000000000000000000000 M g/cm^3 needs a mass of  2800 suns or so before it becomes a black hole while an object with 5 g/cm^3 needs a mass of 4500 suns.

Below the Light Pulse button is a Delete Rings button. This button does exactly what it's supposed to do, delete rings. However, because it only deletes the rings of the object selected, it may not be helpful when you have a lot of rings to remove. Because the Delete Rings button only deletes rings and no other dust, it is useful when you want to selectively delete some dust but not others.

Remember that not all bodies will have all of these options and settings. For example, our Solar system's sun won't have any of the orbital elements because it doesn't orbit anything, (at least not within the Solar system simulation). Mercury wouldn't have a Luminosity or Temperature because it isn't a star.

Physical Properties

You should notice that the top section of this tab is identical to the first section of the Main Properties tab. This is merely for convenience; both sections are identical and work the same.

In the appearance tab, the first control is the color. There is a colored and rounded box to the right of this. Clicking on the box will open up a color palette. After selecting a color from either the presets or the gradient chart, you can click Ok and the window will close. Selecting a color does 3 things. It changes the color of the trail, the color of the highlight mark, and most importantly, it can change the color of the planet.

To the far-right of the color box selector is a check-box for tint. Tint is the option that controls whether or not the planet will turn your color. For example, if you selected blue as a color, checking tint would turn your planet blue. Unchecking tint would return the object to its previous appearance which is determined by its texture.

In the middle of color and tint is an even smaller check-box labeled auto. Checking this will let the computer automatically calculate a balance between the color you selected and the color the object is.

There is a text-box labeled texture below. Here is where you can see which texture a model is using, or even input your own. To use your own texture, you must put it in the folder. The file should be at Documents\Universe Sandbox\Media
Next, type in the name of the texture exactly the same way you name it. The object should now me that texture. If the object is a star, the texture may appear lighter and will seem to glow. If your object has turned into something that looks like the Moon, you've done something wrong.

To the right of the text-box is a button labeled random. This button will spit out another texture each time you press it. Although the textures are in black and white, the color and tint settings above can quickly turn a bleak world into a tropical paradise. If you do not have a lot of memory on your computer, it is a good idea to clear out these textures once in a while. They do not delete themselves and instead of cycling textures, a new one is created every time you press the button. The textures from this should be located at Documents\Universe Sandbox\Media

First in the Mathematical section is Axis. This will draw a line from the North Pole to the South Pole and extends out of the Earth on both sides, allowing you to see which direction the planet is rotating in. In addition, 2 more lines will be drawn, perpendicular to each other and on the equator. The purpose of these lines is to show the speed of rotation. However, you cannot alter the axis of a object with this check-box

The Habitable Zone check-box of a star shows where life could be possible. This is a pretty strange sphere, it is  is determined by Luminosity although it should really be determined by temperature.

The Hill Sphere check-box is just like the one discussed earlier in the Simulation Settings bar. The only difference here is that instead of affecting all bodies, the check-box here will only affect the single body that is selected.

The Lagrange Points check-box is just like the other one discussed earlier in the Simulation Settings bar. The only difference here is that instead of affecting all bodies, this check-box will only affect the single body selected.

The Planet Temp check-box lets the simulation determine the temperature of a planet, or any satellite in orbit around a star or other body. It takes into account all stars that are nearby; a binary star will now heat a planet at a certain distance more than a single star.

The double right arrow button to the right of the check-box opens a small panel with two sliders.

Albedo is the "reflecting power of a surface". It's usually expressed as a percentage or a decimal. A perfectly white surface, (reflects every single color in the sun's spectrum) would have an albedo of 1 or 100%, while a perfectly black surface, absorbing the colors of a sun's spectrum, would have an albedo of 0 or 0%. The slider in the Planet Temp panel lets you adjust the albedo from 0 to 1. From 0.0 to 0.1, you may enter or "slide" up to 3 decimals, or 1/10th of a percent. From 0.1 onwards to 1.0, you may only enter up to 2 decimals, a precision of 1%. Turning up the albedo will cool a planet; turning down the albedo will heat a planet.

Infrared Emissivity is the "relative ability of a surface to emit energy by radiation". Imagine looking into a deep cave. Although the cave seems very dark, it is emitting infrared energy. If i understand this right, the light energy is converted to the full spectrum on infrared energy, heating the cave, air, and/or planet. Infrared Emissivity goes from 0.0 to 1.0, it's slider works the same way as the albedo slider works. Turning up the Infrared Emissivity will heat a planet; turning down the Infrared Emissivity will cool a planet.

A clickable text-box labeled "avg temp" displays the average temperature, in Celsius, of a planet. You can type in this box, but any text entered will be immediately replaced by the temperature of the body. The temperature is not editable using this text-box.

The Roche Limit is the boundary where a larger body will tear apart a smaller body due to gravitational stress. To understand this, pretend you are being carried by two people. The person in front pulls you very fast and hard. The second person has only half as much force in the same direction. If the first person is pulling you with 10 kilonewtons of force and the back person is pulling you with only 5 kilonewtons of force in the same direction, your body altogether is being pullet apart with 5 kilonewtons (imagine the attack of 5000 apples trying to rip you in two pieces). However, instead of two people, larger gravitational bodies use their gravity to pull smallers objects apart. Gravity weakens faster and faster the farther you get from the point of origin. So the pull of gravity from 1 million kilometers will be almost 10 times the pull at 3 million kilometers. It is this weakening that allows stars and other large planets, such as Jupiter and Saturn, to shred smaller objects such as comets, moons, planets, and even other stars. (Spaghettification is just an extreme version of passing the Roche Limit).

Question: Why don't satellites and rockets and even humans fall apart to Earth's gravitational stress?
Answer: The Roche Limit applies to objects that are held together gravitationally, like the moon. If the gravity were suddenly turned off, even slight disruptions could cause the moon and other bodies to fall apart. Black holes are the exception. Because they are so strong, when you get close enough, everything falls apart.

Universe Sandbox simulates objects as a single entity for now and objects can't and won't be affected by the Roche Limits of other bodies. Never fear, we'll see an experiment later that lets us simulate just this.

When you check the Roche Limit check-box, there should be two (wireframe) spheres. The outer one is the liquid Roche limit and the inner is the rigid Roche limit. I'm not clear on the difference and google revealed nothing.

Below the Roche Limit check-box is a sat den value-box. This stands for Satellite Density and is where you enter the density of the object that is to break apart at the Roche Limit. This is an important variable. The denser the object, the more gravity is holding it together, and the harder it will be for a larger body to pull it apart.

If you cannot see anything different after checking the Roche Limit check-boxes, this is because the object not dense enough. The spheres are actually inside the object. Same thing if you only see one sphere.

The Light check-box will cause the object to emit a certain amount of light. This option can only be used on Stars and other light emitting objects. The slider below the check-box can adjust the amount of light that is emitted from the object.  Alternatively, the value-box to the right may be used to adjust the light.

The mini-check-box labeled auto will automatically adjust the brightness of the star to the right levels.

Dynamic Properties

The first text-box is, again, a repeat of the other tabs for convenience,

The three value-boxes in the Position section allow you to move objects at will. Although they can be slow and cumbersome at times, these value-boxes allow extremely precise movements when it is required.

The lock position check-box to the right of the three position value-boxes lets you lock, or freeze, and objects position. Locking the position of an object does not prevent it from rotation. You can still change the position of a locked object manually.

The third section is a repeat from the first tab "Orbital Elements"

In the Rotation section, you can control anything that has to do with rotation. The rot X value-box shows and lets you adjust the rotation time of an object.

The ang X, ang Y, and ang Z value-boxes allow you to precisely adjust the axis of rotation. Just as Earth is tilted roughly 23 degrees off its axis, you can easily adjust the axis here.

Tidal Lock is when the orbital period of a body is equivalent to the rotational period due to the distortion caused by a gravitational gradient. When a celestial body, like the Earth, Moon, or Jupiter orbits the sun, the gravity stretches the body slightly into an ellipse like shape. Because of this distortion, the planet's rotational speed slows until it is equal to its orbital period. The Moon is tidally locked to Earth, which is why we can only ever see one side of it from Earth. The Earth hasn't been tidally locked to the Sun because we are so far away.

http://upload.wikimedia.org/wikipedia/commons/0/04/MoonTorque.jpg

The Tidal Lock button makes the object tidally locked to it's gravitational parent. Because Universe Sandbox assumes objects are rigid bodies, this cannot be simulated by simply placing an object in orbit around another.

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Time/Gravity panel

This panel lets you control both the timestep and/or speed of the simulation. In addition, you can manipulate gravity here.

http://i.imgdiode.com/bMx5JT.png

An important term/concept to know is time step. Time-step is how often Universe Sandbox will calculate the positions of the bodies. For example, if you set the time step of a simulation of our solar system to 2 minutes, universe sandbox moves each of the objects 2 minutes forwards in time and position every calculation, or "step". Setting a simulations time step too high will cause inaccuracies in the simulation. This is because some of the objects might move too far forwards in time and position. If you run the "Shoemaker-Levy 9 crashes into Jupiter in 1994" simulation with a time step too high, the comets will fly through the comet. The program calculates the comet before and after the collision, but not in between.

Notice the double up-arrows in the bottom right corner of the panel. Clicking this will shrink the panel. Clicking the double down-arrows will expand the panel to its current size. When the panel is small, the speed-accuracy slider and the time value-box will be hidden.

The time-step value-box is used to adjust the time-step. Presets are Auto, 2 minutes, 15 minutes, 1 hour, and 1 day. Auto time-step can also be activated by pressing the key "A". Although automatic time step will regulate your simulation fairly well, it isn't recommended for very dynamic, or fast changing, simulations. For example, don't use it on simulations where there are orbiting bodies with highly elliptical orbits and a small SMA (semi-major axis).

There should be a colored circle positioned to the left of the time-step value-box. The color of this box shows if the simulation is running too fast or not. Green means that the simulation is running at a slow and steady speed. Yellow to Red show a higher speed. Elliptical orbits run at this speed over long periods of time my slowly deteriorate. Any faster than this and the simulation will quickly fall apart.

The 1 real sec value-box lets you set the speed of the simulation relative to real time. For example, a value of 1 day in the 1 real sec value-box would set the simulation to one day every second in real time. The presets in this box are, 1/100x, 1/10x, real time, 10x, and 100x.

On the bottom of the panel is a speed-accuracy slider. Moving it to the right will cause the simulation to run slower, moving it to the left will make it run faster. The accuracy is a side-effect of running the simulation slow or fast. Green means that the simulation is running at a slow and steady speed. Yellow to Red show a higher speed. Elliptical orbits run at this speed over long periods of time my slowly deteriorate. Any faster than this and the simulation will quickly fall apart.

Auto time-step will be affected by the sliding of this...slider. For example, if you put the slider on green, auto time-step will keep in on green. If the slider is on red, auto time-step will keep it on red.

There are three circles to the right of the three time controllers, the time-step value-box, the 1 real second value-box, and the speed-accuracy slider. By clicking each circle, you toggle its state from filled to unfilled and vice versa. Clicking each of these will make it control the time. For example, if you had the circle to the right of the speed-accuracy slider filled in, and the slider was on green, the simulation would automatically slow down when it objects are closer to each other, or an object is orbiting close to a star. Clicking the circles to the right of the time-step or 1 real sec value-box just “lock” them, although you can always change them manually. When you fill in either the circle of time-step of speed-accuracy, you'll notice the other one changes slightly. This is because of the computer sometimes running a bit faster and sometimes running a bit slower. It's not significant and shouldn't be an issue. However, if you want the simulation to be as precise as possible, filling in the time-step circle would be a good idea.

On the left of the panel is a big capital G and a value-box. G stands for gravitational constant, but you can think of it as gravity too, gravitational constant is just more correct. Presets are -1, 0, and 1. Changing this value will affect the simulations gravity! For example, setting this value to 5 will make everything get sucked towards each other more. Setting G negative will make objects repel (if they have mass). Try it out and experiment for yourself.

The pause play button pauses and plays. Hopefully not too confusing.

The text on the top center of the panel shows the time. If the simulation was historical, like "Shoemaker-Levy 9 crashes into Jupiter in 1994" there will be a date, accurate to the minute. Simulations like “Our Solar System”, and “Earth & Moon”, which have no specific date, are set to the first day, hour, and second of the year 2008. The objects in the simulation are positioned correctly for that time. If a simulation is not historical, and/or one you created yourself, there will be an amount of time instead, expressed in seconds, minutes, hours, days, years, and millions of years. The time is accurate to 1/100 of a unit, (0.001 seconds, 0.001 years, etc.) and switches to the next unit when possible, (59.99 seconds to 1.00 minutes; 999999.99 years goes to 1.00M years, etc.). This text can reach off the screen if you crank the time-step up enough and wait a while. It is not restricted to within the confines of the panel. However, the time will only be accurate to the first 15 digits. For example, the simulation would show 624,786,264,778,939,000,000,000,000,000,000,000,000,000,000.00 M years.

Body Manipulation Bar

This bar lets you add objects, rings, and particles. In addition, it gives you the ability to physically manipulate these bodies and change their orientation and position.

http://i.imgdiode.com/7a8Vmr.png

Note the Small Panel to the Left, we will start with the Tool on the top right and work our way clock-wise.

The top right Tool, the "Hand tool" is used to wrench and wriggle, and nudge, and push around bodies. You need to be focused on an object to be able to use this.

With this tool, you can change either the position, its orientation, or its velocity.

Click and drag to change its position. It's that easy.

Click the rotational icon, right next to the currently highlighted one, which should be glowing white. Imagine those pretty rings, (technically, they're called tori, or torus in singular form. i call them donuts.) are wheels. Click and spin.

On any moving body, you should be able to see the vector arrow, in the shape of some cylinder cone object, (circular obelisk?), Click and drag this. Unfortunately, you must stay on the same plane when using this tool, it doesn't allow you to move out of the place.

The bottom left Tool add's bodies. It's name, "Add tool", does not mean it adds tools. It is a tool used to add.

You cannot add objects from scratch in this program. You must add a preset one and change it to your desires.
There are several tabs on this bar, but they mostly all do the same thing.

The first tab is the galaxy tab, note that IC 1101 is insanely huge. Galaxies show here include the

-Milky Way
-Andromeda
-Triangulum
-Large Magellanic Cloud
-Small Magellanic Cloud
-NGC 300
-NGC 55
-M110
-M32
-IC 1101

In that order.

In the second tab contains a variety of stars.

-The Sun
-Rigel
-Alpha Centauri A
-Alpha Centauri B
-Wolf 359
-Sirius
-Polaris
-Alderamin
-VY Canis Majoris
-Pollux
-Arcturus
-Mu Cephei
-Betelgeuse
-Antares
-Aldeberan
-Deneb
-VV Cephei
-Barnard's Star
-Eta Carinae

The third tab, a planet tab. It contains all the planets of our solar system and more.

-Mercury
-Venus
-Mars
-Earth
-Jupiter
-Saturn
-Uranus
-Neptune
-Eris
-Pluto
-Ceres
-Haumea
-Makemake

In the next tab, moons. Our own moon is labeled, simply, "Moon".

-Moon
-Titan
-Europa
-Ganymede
-Dione
-Mimas
-Io
-Callisto
-Triton
-Iapetus
-Miranda
-Pandora

The next tab is a Asteroids tab. The icon, strangely, appears to be a comet. Unfortunately there is no way to make comets leave trails, (i even tried making some sort of dust emiter with 2 objects rubbing against each other in bounce mode). Note that Ceres appears in this tab and also the Planet tab.

-Ceres
-Pallas
-Vesta
-Ixion
-Orcus
-Sedna
-Apophis

Here you can find objects ranging from teapots to monoliths. (The Football is called a Soccer ball, depending on where you live).

-Pool Ball
-Football
-Baseball
-Bowling Ball
-Teapot
-Dice
-Monolith
-Ring

The last tab adds rings. To use this, you first focus on your object which you want to add rings to. You then pick a ring and click. A geosynchronous ring is one that rotates the planet at them same speed the planet rotates. To an observer on the ground, it would seem as if the ring never moved. The faster the planet rotates, the faster the ring must too, so it is lower. A low rotation speed means the ring is high up, or far away from the planet. To be able to add the geosynchronous ring, your body must be rotating. The other rings available are Jupiter, Saturn, Uranus, and Neptune.

Once you add a ring, a new panel will appear and you can effectively edit the ring. This is the ring panel

http://i.imgdiode.com/1VLDRm.png

The box labeled "orbit" shows the object the ring is orbiting. You cannon change or manipulate this in any way. Clicking the large up-arrow to the right of this will open the Object Editing Bar of the orbiting body.

The inner and outer value-boxes control the inner and outer radius of the ring. Presets are 1, 2, 5, and 10.

The units are kilometers, normally, but filling in the check-box labeled "Measure in radius", will let you chose the size of the ring based on the number of radius away from the object it's orbiting. If there is a planet with a radius of 7000 km, and a ring orbiting around it at 2 radii, the ring will be 14,000 km away from the center of the planet.

The "count" value-box changes the number of dust particles in rings. Good when you want a fairly solid looking ring, or need to lessen the load on your computer. Presets are 100, 500, 1000, 2000, 5000, 10000.

The drop-down box below shows the type of ring you currently have. Helpful when you don't feel like editing your own ring. You can just switch between rings here. Options include Normal, Jupiter, Saturn, Uranus, Neptune, Rainbow, and Awesome.

Normal rings are just normal. Jupiter, Saturn, Uranus, and Neptune rings look just as they should. Rainbow rings are rainbow colored, and Awesome rings are a violet to orange gradient of color.

The X mark to the right does exactly what it says, deleting the last ring added to the body.

The Reverse orbit check-box will reverse the rotation of the ring.

The "Replace Last Ring" button replaces your last ring. For example, if you had a Neptune ring around the moon, but Earth started ripping it apart, then you would press "Replace Last Ring" and a brand new Neptune ring would spring up around the moon. The old ring should be completely erased. In addition, this button also works as a toggle, when it is selected (most of the time it is, it is a default setting), any new rings you add will overwrite the old ones and erase them.

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The "Add New Ring" button does the opposite. It also toggles the deletion of old rings. When you press this button, the toggle is switched to keeping the old rings. This means you can have a Jupiter, Neptune, Uranus, and Awesome ring on the same body. You can even have more than 1 Jupiter, or Neptune, etc, ring!

That's the Ring panel, now going back to the Body Manipulation Bar.

If you click on any of the tabs besides the "Rings" tab, you will notice that there are 3 buttons on some sort of bar. These buttons will control how you bring an object into the simulation. The settings are "Add bodies with Automatic Orbit", "Add bodies with No Set Velocity", and "Launch Bodies".

Add bodies with Automatic Orbit
When you chose this option, your bodies will automatically orbit their gravitational parent. Good for creating solar systems or just adding moons and random bodies. To use, select an object from the various tabs. Then, move it into the screen area. You should see a polar grid.
If there is another large gravitational body than your object can orbit, you should be able to see a circle, which is it's projected orbit. If there is no larger gravitational parent, you should not see a circular line. However, if there is no other bodies at all, then your object will be at the center of the polar grid. You're selecting the center-point of the grid depending on where you place your object.
To place the object, just click. If you want to change the inclination of an objects orbit, or want to change an objects "height" just click and drag up. Release when you've reached a desired position.

Add bodies with No Set Velocity
Bodies added this way let you select your starting position, direction, and speed. Helpful in orchestrating collisions, planet flybys and more.
To use, select an object from the various tabs. Then, move it into the screen area. You should see a polar grid.
Then, click and drag. A cylindrical arrow shape should extend from the planet. The direction you drag, and how far you drag determines your velocity (speed and direction is velocity). Keep in mind that the first body in a simulation cannot be given velocity by dragging.

There is a relative velocity check-box under this option. It makes the velocity of the body relative to whatever you are focused on. Pretend, for a moment, that Mercury is falling towards the sun at a speed of 10 km/s. Of course, it would accelerate, but we can ignore that right now. If we wanted to simulate a rocket leaving Mercury, carrying the survivors of an alien species, we need to know how fast it should be moving. The rocket travels at a constant speed of 50 km/s; in the opposite direction of the Sun. However, since Mercury is traveling towards the sun at 10 km/s, you only move 40 km/s away from the Sun. So, when you go simulate this in Universe Sandbox, check relative velocity before you launch that spaceship at 50 km/s. Of course, the problem in my example was easy enough to figure out with mental math; this won't always be the case.

Launch bodies
This is the last way to add an object (and personally, my favorite). This lets you fire bodies our of your cursor, like some ancient Universe Sandboxer raining down rocks of doom upon the dinosaurs.
There are a lot of Options and stuff, but this is how i normally use this mode.
1. Select appropriate body (not too big and swallows the system)
2. Set velocity to appropriate rate (look, 10 m/s is really painfully slow in a galaxy collision)
3. Aim
4. Press the "F" key as hard as you can.

There is an Add Body button which will fire the object, but i prefer pressing "F". It's so much faster and easier.

The value-box labeled "vel", which stands for velocity, is a pretty cool guy. Use him to adjust the velocity and make sure you don't get neutrino like objects which travel straight through jupiter. When you fire a galaxy, its dust stays with it. However, if you manually manipulate its velocity with the Object Editing Bar, you will get an shapeless mass of dust pretty soon.

The thingy on the bottom left, also known as the “Box select”, lets you manipulate multiple bodies simultaneously. Multi-body controls are expected to be improved in the new future; i'll update this as soon as possible if and when that happens.

Before you use this, go create or find several bodies, (two is enough), and select them. It's just as simple as click and drag to create a box; i'm sure you've done this before.

A panel will appear, hopefully looking something like this.

http://i.imgdiode.com/KubkMZ.png

On the top, text displaying how many bodies are selected.

The “Zero Velocities” button makes every object have a velocity of 0.

The “Reverse Velocities” button, (shortcut “r”), reverses all velocities. Neat because it reverses all the dust in galaxies and preserves their shape.

The “Make binary Orbit” button, will force two objects to orbit each other.

The “Add Barycenter” button will create a barycenter. A barycenter is the center of gravity. If I selected all the bodies in the solar system and clicked “Add Barycenter”, the barycenter would most likely be near the center of the sun; it's the center of the solar system and contains 98% of it's mass.

The “Orbit Parent” button will make objects orbit their gravitational parents. Press “;” the semicolon key too see what an object's parent is. Not sure of the difference between this and Auto-Orbit. I suppose with Auto-Orbit, you either have to apply it to the whole simulation, or one body at a time. With the Box select, you can selectively apply it.

Below should be 3 boxes. K energy, P energy, and Momen. You cannot change these values. Although you can type in another number, the box reverts itself as soon as you press enter.

K energy stands for Kinetic energy. Kinetic energy is energy of an object's movement. A bullet has a lot of kinetic energy and can rip through flesh and bones. Planets also orbit at high speeds around the sun. This is kinetic energy.
 

P energy stands for Potential energy. Potential energy is the amount of energy stored in an object due to its position or configuration. For example, an iron weight lifted off the ground has potential energy. If you drop it, the energy will be released in the form of sound heat and physical movement. In Universe Sandbox, potential energy is the amount of energy stored in the objects, just like the energy stored in the iron weight.

For some reason, the value of the Potential energy box will change for several seconds after the simulation is paused.

Momen stands for momentum. Momentum is the amount of motion for a certain mass in an object and the velocity of that motion. A car can not instantly stop when brakes are applied because of momentum.

It's important to note the difference between Kinetic energy and momentum. Kinetic energy is a value, while momentum is a the amount of force in a direction.
For example:
a bullet weighing 10 grams and moving at 2000 m/s
has 20 kg m/s of momentum
and 20 kj (kilojoules) of kinetic energy

On the other hand, a 5 kg bowling ball moving at 4 m/s
has 20 kg m/s of momentum
and 40 joules of kinetic energy

While getting hit by the bowling ball might hurt a bit, it won't kill you like the bullet probably could.

The next box shows the total mass of all the bodies in a simulation. This is rounded to the nearest hundredth of a unit.
Units include
-kg (kilograms)
-Moons
-Earths
-Suns
-Milky Ways

Strangely, clicking on either the box or the filled in circle to the right of the box will cause Universe Sandbox to crash.

The check-box labeled Auto system lets you selectively use Auto orbit. Instead of using auto orbit on the whole simulation, you can just use it on two objects. This is extremely useful because a blanket auto orbit on the whole simulation messes with inclinations of orbits.

The two buttons on the very bottom on the multi-body panel lets you create a cable between two objects. A cable is a flexible line made of multiple connected rigid segments. A cable will gradually deteriorate, wobbling more and more as time goes on until your screen is filled with flashing lines. Auto time-step does not seem to apply on cables. Cables will not collide with bodies. Currently, only 1 cable between 2 bodies can be created. If you want a cable that will last indefinitely, turn the segments value to 1.

Cables are 1 pixel thick and colored green. Towards the end of each segment is a gradient towards white; the end of each cable is which.

The button on the right, labeled “Connect Bodies with Cable”, creates a cable between the two bodies with the options you have set. If you haven't set any options, the cable will have default values.

The button the right, labeled “Advanced Cable Options”, opens another panel which allows you to change the cable. The 5 values can be changed through either the value-boxes or the sliders.

The Segments value determines the number of section the cable has. Each section of the cable is completely rigid and cannot be bent. As a result, all movement occurs at the joints. More segments mean more joints, which means more realistic and flowing motion.

Mass @ meter in kg changes the mass of the cable. It does not seem to pull objects together with gravity. Turn this value way up high. It stabilizes your cable.

Interfriction seems to be the value that controls the amount of friction between cable segments. I would turn this down; it drastically increases the time before a cable wobbles out of control.

Stiffness is how much cable joints can bend. A low stiffness will let you see easily, a moon dragging a cable around a larger planet. However, I turn this down because it reduces the cable wobble.

Stiffness multiplier seems to control how easily cable joints can bed. I turn this down because it reduces cable wobble.

To understand the difference between stiffness and stiffness multiplier, imagine an arm (either robotic or human will work). Stiffness is how much you can physically bend. Can you touch your toe to your ear? Lick your elbow? Stiffness multiplier is how easily you can stretch. How long does it take you to do a split or tie yourself into a knot?

http://i.imgdiode.com/ZTaWPd.png
http://i.imgdiode.com/DOl4It.png

The last tool, labeled “Normal Tool” is located on the top left of the box. It's pretty simple and its only function is to click buttons and objects. (All other tools can be used to click all the buttons too.)

Mode Panel

The Mode Panel consists of 3 buttons on top of each other.

http://i.imgdiode.com/bitO8d.png

The button resembling a sun, labeled “Live Mode” is the default mode. It just runs the simulation as usual. This is the mode you spend most of your time in, creating solar systems and playing with gravity.

The second button, resembling a pencil or pen on a blank sheet of paper is labeled “Edit Mode”. In this mode, all the objects on your simulation will be on a 2-dimensional grid comprised of circles and squares. From the center of this grid, a line rises up to the celestial north pole. In this mode, the simulation is automatically paused. Pressing the play button causes the simulation to revert to Live Mode. Pressing the play button again will cause the simulation to unpause.

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The last button, or “mode” is labeled “Chart Mode”. Pressing this will put objects into a specific order depending on various variables which you can select from. Pressing the play button in this mode will switch toggle the simulation between Play and Pause. However, the mode will not change and the objects will remain frozen, unable to move. Chart Mode does not sort dust. The dust remains in its previous position.

You can sort objects for:
-Mass
This is the amount of matter in an object, basically.

-Diameter
The diameter is the length of the line between two points on the surface of the sphere which are as far away from each other as possible.

-Density
Density is mass/volume. A lead weight is denser than an ant (pun intended).

-Velocity
Speed with a direction. Although direction isn't really relevant here.

-Acceleration
How fast an object is speeding up or slowing down. (Slowing down would be negative acceleration).

-Temperature vs Luminosity
This option will create a different kind of chart. The bodies sort themselves on a plane instead of a line. To see, this, open the “Stars-Nearest 50” simulation and switch to chart mode. Click Temperature vs Luminosity. This is the Hertzsprung-Russell Diagram. The stars on the central band are called “Main Sequence” stars, while there are a few outliers. On the y-axis of this chart is the temperature of a star. Notice that blue and white stars are up higher than the yellow, orange, and red stars near the bottom. This is because hotter stars emit a blue and white color while cooler stars emit red or orange light. On the x-axis is the luminosity. The dimmer the star, the farther to the right it is.

-Mass vs Diameter
This will sort the objects based on mass and diameter much like the previous option. Mass is on the y-axis while diameter is on the x-axis. You should see a pattern. Heavier and larger stars are generally brighter and hotter, making a blue color, while smaller and lighter stars are generally dimmer and cooler, making a red tint.

-Radius vs Density
This option sorts objects based on radius and density. Radius is on the y-axis while density is on the x-axis. If you are using this with the “Stars-Nearest 50” simulation, you should notice that many of the stars are clumped together tightly while there are several outliers which are spread out. Delete these outliers to let you see the general trend better. You should see the stars in an exponential curve; from the top left, curving down to the bottom left and then to the bottom right. This shows; the larger the star, the less density it has. This happens in an exponential pattern because volume grows exponentially every time the radius does; and density is dependent on volume.

-Name
Sorts the objects alphabetically.

-Distance
This is the distance from the the most massive body in the simulation.

-Random
This option randomly sorts the stars in space. However, it is not without bugs.
If you use this option after sorting for objects after selecting Temperature vs Luminosity, you will get most of the objects very close to a common plane. If you select this after using the Mass vs Diameter option, you will get the objects on a line. If you select this after using Radius vs Density, you will get the objects very close to a line. And if you select random after selecting original, all bodies will be on top of the same point.

-Original
This moves the bodies back to their original positions.

There are two buttons on the top left corner of the Chart mode panel. One is labeled “Arrange objects with even spacing”. The other is “Arrange objects proportionally by value”. “Arrange objects with even spacing” is the default option.

Mercury is about 2 and a half times closer to the Sun than the Earth. If I had the chart mode set to “Distance” and “Arrange objects with even spacing”, then the distance from the Sun to Mercury and Mercury to the Earth would be the same. However, if I had the chart mode options set to “Arrange objects proportionally by value”, then the distance from the Sun to Earth would be 2 and a half times greater than the distance from the Sun to Mercury.

The switch on the top left of this panel consists of two buttons, Arrange objects with even spacing, and Arrange objects proportionally by value. When you press one button, the other one is deselected. By default, Arrange objects with even spacing is “switched” on.

Arrange objects with even spacing puts objects the same distance away from each other. (The distance is from the surface of one body to the surface of another, not the center).

Arrange objects proportionally by value sorts the bodies by value.

For example, imagine 1 stars, one with a mass of 1 sun, one with a mass of 2 suns, and one with a mass of 10 suns. They would all appear equally far away on the “Mass” chart if Arrange objects with even spacing was selected. However, if you pressed Arrange objects proportionally by value, the stars with 2 and 10 sun masses would be 8 times as far away as the stars with 1 and 2 masses.

The slider below the Arrange buttons can only be used when “Arrange objects proportionally by value is selected. When you move it to the right, objects become more stretched out. When you move it to the left, objects come closer together. If there is not enough space for all objects to fit, the objects will start to stack on top of each other.

The check-box “Auto Camera” , below the slider, makes sure that all bodies are within view. It'll zoom out when the chart is big and zoom in when the chart is small so that it fills most of your screen. By default it is on.

The check-box “Headlamp”, below “Auto Camera”, shines a light from the player's POV to all objects. By default it is on. Not necessary when doing Chart mode with stars, but it is helpful when looking at planets.

The button labeled “Make Live” will unpause the simulation without putting objects back to their original position, and run the simulation. The simulation will automatically switch back to Live Mode.

View Panel

This panel lets you change the way the universe looks to you in addition to letting you take screenshots and videos easily. The shortcut key for screenshot is F12 by default.

http://i.imgdiode.com/DaCQkt.png

The view panel is comprised of 2 sub-panels and many more buttons.

This is the Camera Orbit Panel. It lets you control your camera's autorbit.
http://i.imgdiode.com/nPhA7k.png

The checkbox controls whether or not to rotate. By default, the camera does not rotate. The H and V value-boxes stand for Horizontal and Vertical, they control movement in that direction. Vertical movement is limited. When you hit the “top” or “bottom” of the simulation or screen, you'll stop moving. There is no such limitation for horizontal movement

The Screenshot Panel . It lets you take screenshots or record videos
http://i.imgdiode.com/Tlw8YY.png

The “Take Screenshot” button takes a screenshot. A shortcut for that is f12.

A folder button to the top right opens the folder where all your screenshots for universe sandbox are stored.

The “View last screenshot” opens your most recently taken screenshot with a default image view, (usually windows photo viewer).

“High Resolution Screenshot” takes 9 screenshots of your...screen and combines them to create a larger and clearer image. (You don't have to manually combine them, the program will churn out 1 picture.)

Clicking the “Layered Screenshot” button takes several screenshots. One of the background, one of the simulation, one of the labels, one of the interface, and it also creates another image will all the seperate layers combined.

On the bottom, the check-box and value-box can be used together along with another program to create a movie.

Checking the “Capture Screenshot every...” option will take a screenshot every “X” frames. You must determine “X” by filling in the value-box. A typical video runs at around 30 fps.

The folder button on the bottom right of the screen opens the folder where your “movie” screenshots are saved. They are stored in a seperate folder to prevent clogging up your normal screenshot folder (I had 96,000 frames to put together after a night of recording).

To make a video, you must first install a program that will put frames into a video for you. I use Virtual Dub here at http://www.virtualdub.org/ just run the program and create the movie.

Going back to the main “View Panel”, the drop-down box on top lets you Adjust your color mode. The color mode is “realistic” by default

Realistic: It's....real. The Milky Way is blue and Andromeda is white though in this color mode.

Velocity: Sorted by speed. From fast to slow, the colors are: Red>Yellow>Green>Blue>Pink

Acceleration: Sorted by acceleration or deceleration. From Acceleration to Deceleration the colors are: Red>Yellow>Green>Blue>Pink

Mass: Sorted by Mass of object. From largest to smallest the colors are: Red>Yellow>Green>Blue>Pink

Physics Group: Bodies start out monochromatic. When two uncolored bodies collide, they randomly turn a certain color. When an uncolored body and a colored body collide, the uncolored body turns the color of the colored body. When two colored bodies collide, one body turns the color of the other body. When groups of bodies collide, the same thing happens. It does not seem to matter which group is larger. Colors used: Red, Green, Blue, Violet, Yellow, Turquoise, Brown, possibly more.

Monochrome: Turns all bodies a grayish shade. Use with 3d if you have trouble seeing the “3dness”.

Vivid: Turns bodies randomly to random color. Colors Used: Purple, Green, Orange, Brown, Blue, Red, Yellow, Pink, Turquoise, possibly more.

The text-box box labeled “Center of the Universe” lets you center the simulation. By default, there should be “Absolute Space” in the box. Everything is relative, it matters where you are looking from. To use this, you must first select an object. A “+” sign should appear on the right edge of the text-box. Click it to set your selected object as the center of the universe. An “X” should appear on the right-edge of the text-box. To remove an object as the center of the universe, click this “X”.

http://i.imgdiode.com/InFsrt.png

The center left side of the View Panel should have 2 buttons, the magnifying glasses. Click to zoom in, and click to zoom out. Or use the keyboard for zooming in and out, (“w” to zoom in, “s” to zoom out).

In the middle of the panel should be a button labeled “Change FOV”. Clicking on it will open a little box. I refrain from calling it a “panel” because it'd pretty small and only contains a single slider and a button.

The slider lets you set your FOV. A larger FOV means you can seem more, but everything looks smaller. A smaller FOV means you can't see as much, but everything looks larger. The Hubble Ultra-Deep Field images would have a very small FOV while glancing at the night sky gives you a larger FOV.

[vh]

The reset button resets the FOV to a default of 60 degrees. The human eye can see 170 degrees or so. The Hubble Ultra-Deep Field is about 1.5% of a degree.

The textbox labeled “Scale Width across your view” is the distance, from the left side of your screen to the right side of your screen, that intersects your camera focus, (whichever object you are focused on, if you are focused on one). To understand this: Hold up a ruler 2 inches from your eyes. How many inches can you see on the ruler? Hold the rules an arm-length from your eyes. You can easily see the whole thing. The amount of “ruler” you could see is the “Scale Width across your view”. The center of the ruler itself is the “focus”.

Keys 1.3

Keyboard controls are a vital part of Universe Sandbox. Even though you can do most if not all things with just the mouse and the various bars, panels, and options, a keyboard shortcut is just so much faster and more convenient. The full list is at http://universesandbox.com/help/controls/ , but I'll post it here too for your convenience.

Code: [Select]

MOUSE
Left Click
Select a body.
Click a selected body to focus on it.
Right Click Click on a body to show properties pop-up.
 
Click and Drag Rotate your view around the focused body.
Mouse Wheel Zoom in and out
Keyboard
Main Controls
ESC Show / hide the Menu
Enter Show / hide the Control Panel
 
Alt + Enter Toggle windowed / full screen
Tab Show / hide play button & clock
 
Ctrl-O Open a system
Ctrl-S Save a system
Ctrl-R Restart the current system
Ctrl-F Show the Find Tool
 
F1 Quick reference info
F2 Open a system
 
 
SYSTEM COMMANDS
F Create a new body
Z Zero system momentum
X Halve all velocities
O (the letter) Orbit All - forces all bodies to orbit their current gravitational parent
 
 
SIMULATION CONTROLS
Spacebar Start & stop time (play/pause)
E or Numpad + Speed up time
D or Numpad - Slow down time
A or Numpad Enter Auto time step
R Reverse all velocities
Ctrl-Numpad Enter Real Time (where 1 simulated sec = 1 real sec)
 
= (plus key)
Increase gravity
- (minus key) Decrease gravity
0 (the number) Turn gravity off
9 Set gravity to 1.0 (normal)
8 Set gravity to 0.5
7 Set gravity to 0.25
6 Set gravity to -1.0 (negative)
 
U Toggle between collision modes
 
Shift-i Change the collision elasticity in bounce mode.
 
BODY COMMANDS
Select a body to use these commands.
V Light Pulse
Ctrl-W
Sets the radius of the body so that its escape velocity equals the speed of light (this is the Schwarzschild radius)
P Set body to the center of the system. This shows all movement of other bodies relative to the hovered body.
M
Move Body:
Hold down this key and move the cursor to move the hovered body.
N
Rotate Body:
Hold down this key and move the cursor left or right to rotate the hovered body. While holding down the key also press Shift or Ctrl to rotate on the other 2 primary axis.
 
 
VIEW CONTROLS
W or F7 Zoom In
S or F8 Zoom Out
 
Shift-F7 Decrease Camera FOV (field of view)
Shift-F8 Increase Camera FOV (field of view)
 
B Show / hide bodies
T Show / hide trails
L Show / hide labels
H Show / hide highlights
G Show / hide grid
; (semicolon) Show / hide relationship lines (connects bodies with their gravitational parent)
 
Ctrl-D Clear dust
Ctrl-T Clear trail data
 
C Next color mode
Shift-C Previous color mode
Ctrl-C Toggle 3D mode on/off
 
Ctrl-B Toggle Background on/off
Ctrl-G Toggle Glow on/off
 
Q Toggle drawing size of bodies (always visible or true to scale)
 
[ Decrease # of drawn trail segments
] Increase # of drawn trail segments
 
Shift Show a body's Hill Sphere
(while hovering over it)
Ctrl Show a body's Lagrange Points
(while hovering over it)
 
 
CAPTURE CONTROLS
F4 Toggle movie record (multiple screenshots)
 
F9 Take hi-res screenshots
F12 Take screenshot
Ctrl+F12 Take screenshot with UI
Ctrl-F2
Shift-F2
Alt-F2
Set hi-res screenshot to 2x2, 4x4, or 5x5 (default is 3x3)
 
 
EXPERIMENTAL AND UNFINISHED FEATURES

Shift-B Toggle between different calculation modes for particles/dust. (effect is not obvious - the default mode is more accurate)
Ctrl-N Toggles between normal and Modified Newtonian Dynamics (currently disabled)
J
Strange forces - Causes bodies to repel each other when they get too close. Works great with the simulation "Moons, small cluster"
(This isn't based on anything real.)
3 Restore saved camera position (not currently working)
Ctrl-F7
Ctrl-F8
Adjust engine scale (outdated controls, no longer works)
Ctrl-1
Ctrl-2
Ctrl-3
Ctrl-4
Ctrl-5
Quick load a specific simulations (used for testing)
Y Fire a 'photo torpedo' - Triggers an explode command on any body it intersects
Ctrl-L Toggles experimental light mode
F3 Toggle between zoom and normal modes (not currently working)
Shift-R Create rope between body #1 & #2
Ctrl-Shift-R Show/hide rope slider controls
   

Note that some of the commands here have been outdated.

-Ctrl-N makes trails thinner.
-B does not hide bodies; the correct command is Alt-B.

[Dan Dixon]

Wow... This is really incredible. I just stickied this thread.

Although this content might be more useful as a webpage (which would be pretty easy to put together) or on an official wiki (which would take more time to setup). Either way... it's great as is.


And... Alt-B will hide the bodies.

[FiahOwl]

This is just pure  amazing.

[FiahOwl]

In this section a summary of each option, knob, slider, check-box, drop-down box, and/or anything other option will displayed along with any tips and tricks. At the bottom of each will be a screenshot if appropriate (For example, i won't have a screenshot for accuracy mode; you can't show that.)

[atomic7732]

Woah, this is awesome and it's way too long for me to want to read, but then again I already know how to use US. I tried doing something like this on the wikia. Had the layout of wikia not changed so that only like half the screen is the content you want to see I would have recommended you putting all that there so that there would be links to sections and embedded pictures and stuff.

[vh]

Yes, Dan said something about putting it on the wiki.

Also, updated to 2.1.4
working on 2.1.5 and new images, but i've been busy.

[Yannos]

I usually end up having 10 tabs simultaneously open in Chrome when messing around with Ubox.

Now, with your help those are reduced at least by 5. 

Thank you so much for making this.

[mjduniverse]

Too long, better on a webpage And Also Inefficent.

[vh]

Possibly, it gets easier when you search using the ctrl-f key combination to make it easier to navigate. This guide is supposed to be long so it covers everything about universe sandbox. If you want to read something short, do the tutorial in universe sandbox or read the short blurbs that appear when you hover over a button in universe sandbox.

[nick222238]

uhh iv already purchased universe sandbox but i cant play it it says i have to purchase it first before i can download full version but sinse then iv moved to another computer what do i do??

[vh]

Just scroll up to the top of the page and click the button on the top right to install universe sandbox. Then insert your verification code that you should have been sent in an email.