Universe Sandbox ² | Alpha 7 Preview Video

[C7]

Here you go, finally had a chance to record the video. I hope you like it

https://www.youtube.com/watch?v=2FrYlxJj8j4&list=UUxJjsUsKXjvUbfbQ2pd51-Q

[JAW1002]

My goodness, can I have it now? :'D

[smjjames]

Nice!

Also, it would be cool if it transitioned through gas giant, to brown dwarf, to low mass red dwarf and then upwards rather than gas giant and then poof, it turns into a star.

Can we do something like the Earth-Theia impact theory of Moon formation? Though you did manage to get a fragment into orbit with that last impact.

[JAW1002]

Will the fragments inherit the momentum of the colliding object? From the video it looks like it spreads out evenly in all directions, thinking of the Earth- Theia theory like smjjames.

[smjjames]

As for the angular momentum, hard to tell because the camera moves around, but the angle of the object seems to be both retrograde and the wrong angle.

Though yeah it seems to be mostly random rather than mostly a spray in one direction.

[C7]

Will the fragments inherit the momentum of the colliding object? From the video it looks like it spreads out evenly in all directions, thinking of the Earth- Theia theory like smjjames.

That's a very straight on collision, so the debris are spread pretty evenly. You'll get much different behavior from an impact that is off center, or against a rotating planet. I've tested a lot of different scenarios, and had some pretty interesting results.

[Cosmos]

Amazing video. I can't get enough of this amazingness.

[C7]

This one is just for fun

https://www.youtube.com/watch?v=KMH7pigByV8

[gabriel.dac]

Amazing! This will be the version I'll test the most!

I've got a few things to say

• When you added silicates to Mars, it turned into a star. Is that really accurate? Can you create a star out of sand?
• I think that the "properties" list of each celestial body is getting a little too long. There is a new section in it that includes all the materials on the surface of the planet now, as far as I know. In my opinion the list is getting too long. I think it would be better if you split it into different tabs.
• Add splashing sounds when the water hits the planet! I know there is no sound in space, but considering you added sounds for collisions, why not add sounds for water too?
• when the moon collided with Earth in your bonus video, that gave me a little heart attack. You should have added a warning  (haha jk)

That's it. Keep up the good work

[Bla]

Amazing, that also looks like a lot of new, nice work since the alpha 7 preview Dan sent me.

That second video... LOL

[Naru523]

Interesting update. Especially with the modeling.

[shadow6061be]

Wow.
Seeing the work that has been done on collisions... I could not even imagine such an improvement being made !
It just fills one of my dreams : melting planets away by "space-bombing" them, or just simulate collisions on a 1:1 time scale just to see what it would kind of look like...

I have to say that, for what it is worth, you have my most sincere congratulations for the incredible work you are all doing. Thank you all for letting us have the opportunity to manipulate the universe at will.

[gabriel.dac]

Wow.
Seeing the work that has been done on collisions... I could not even imagine such an improvement being made !
It just fills one of my dreams : melting planets away by "space-bombing" them, or just simulate collisions on a 1:1 time scale just to see what it would kind of look like...

I have to say that, for what it is worth, you have my most sincere congratulations for the incredible work you are all doing. Thank you all for letting us have the opportunity to manipulate the universe at will.

There's still lots of work to be done. I've been asking for quite a while for them to add friction in collisions, so the planets won't bounce off when they collide at angle

[shadow6061be]

Wow.
Seeing the work that has been done on collisions...[...]Thank you all for letting us have the opportunity to manipulate the universe at will.

There's still lots of work to be done. I've been asking for quite a while for them to add friction in collisions, so the planets won't bounce off when they collide at angle

Of course there is still a lot of work to do, but as a future programmer myself (business software oriented), I admire these kind of accomplishments...

TL;DR version :
From my future programmer point of view, I can imagine how much work they are putting into making this game, and I really appreciate the fact that the programmer themselves interact with us via these forums and really care about their game instead of pure profit (which sadly can't be said of all indie teams out there ).

Long version :
They manage to simulate the collision of the moon and the earth on a home computer while I struggle to let a program display the required text-based information (no matter how realistic these collisions are or not, Giant Army still do have an impressive amount of work done right there, especially as an indie team).

As I said, I will eventually become a programmer (the official name is "Analyste programmeur" so I guess it translates to programmer/analyst) so I am learning both ends of programming and I can relate to how hard it can be to do some of these things. Now, of course, I still don't have the experience of work, as I am only having my exams for the second year out of three right now, so I can't relate to any real life experience other than trying to figure out why a problem happens in a small 3000 lines program, I can only imagine how much work it is to code such a game.

And so, from my point of view, doing such a job is really great, and we can sadly not say that from every indie team...


PS : I speak french so sorry if made any atrocious mistakes. I'm open to grammatical corrections as far as they are constructive. So don't hesitate if you see me writing an horrible sentence ^^.

[dechireur77]

Will we be able to load an asteroid with water and send it on a planet. In order that the oceans formed on the planet ? if two rocky planet collide and fragment of planet does not fall on the planet, it's fragment can form a moon ?(If two rocky planet collides, the fragment that will be able to eject t he form a moon?) (Sorry if I made ​​mistakes, I'm not hyper strong in English ...) At the same time can you give me your configuration for appearing to mine?, because your games and very fluid 

[smjjames]

if two rocky planet collide and fragment of planet does not fall on the planet, it's fragment can form a moon ?(If two rocky planet collides, the fragment that will be able to eject t he form a moon?) (Sorry if I made ​​mistakes, I'm not hyper strong in English ...)

That's the Earth-Theia impact theory. Though it's more than one piece of debris which coalesces into a moon. In the first video, there was one fragment that managed to get into an orbit (I think), so, yeah, if the angle and speed are just right....

[Greenleaf]

Will the fragments inherit the momentum of the colliding object? From the video it looks like it spreads out evenly in all directions, thinking of the Earth- Theia theory like smjjames.

They will and they do.
Before, during and after a collision, the linear and angular momentum is conserved.
This also has the effect of turning angular momentum from a pair of colliding bodies into spin momentum on the remains, so you can essentially have a collection of n planets with some momentum, have them collide and see the momentum conserved.
The energy estimation during impacts is actually based on this conservation by looking at mechanical energy before and after, while conserving momentum.

... but that said, for testing purposes, a certain randomness has been added to the direction in which fragments spray. It is hard to make two perfect spheres collide and fragment correctly, so for this mode certain tweaks are in plane. Still conserving momentum though ;-)

[Greenleaf]

There's still lots of work to be done. I've been asking for quite a while for them to add friction in collisions, so the planets won't bounce off when they collide at angle

Then you will be pleased to hear that some collision forces have been added.
In a sense, there is nothing wrong with bounding off. That can certainly happen for shallow angle impacts.
When two large bodies collide, they will deform and that will slow them down by giving a repulsive force. This force will make bouncing even more likely, since this force acts to push the bodies apart.
At the same time, for shallow angle impacts, the spheres overlap in a lens shaped region and this body of material is essentially dragging both bodies at that point opposing the relative "sideways" velocity.
This has the effect of slowing the bodies relative velocity even more while additionally imparting torque.

nb. Obviously two colliding bodies don't "overlap". They flatten and deform, but in this collision mode the planets are spheres.

For even more accurate collisions, we have implemented a SPH (Smoothed particle hydrodynamics) which does dynamic deformation and fragmentation, but it is not yet ready for public release.

[Greenleaf]

Can we do something like the Earth-Theia impact theory of Moon formation? Though you did manage to get a fragment into orbit with that last impact.

It is actually very complicated to make that specific collision (proto earth+Theia) give that specific result (Earth+moon). I will say that in this collision mode, you can get somewhat similarly looking results, since the tech is there. Fragments do get spawned, angular momentum does get conserved and fragments do coalesce into larger bodies.

I have some experience simulating that specific impact with SPH, and even with a much better numerical scheme like that, and running it offline, it is no simple task. The actual collision is not too complicated, but the behavior of the vaporized and ejected material when it cools down and starts forming larger and larger fragments, that is hard :-/

As I recall it, with a simplified equation of state, and months of hand tuning I did actually create an "earth" and a moon, though the moon was a little on the small side and was orbiting a bit too far out. Point being, with universe sandbox running at interactive speeds, you get simplified reasonably plausible results, so such a specific case would be hard to replicate.

SPH is in the works and will give results somewhat similar to this
Please read description on youtube.

http://youtu.be/eZkhbWzepM4 and this
http://youtu.be/UUVNuA-1ovM

which are some of my very old videos of a simpler cpu implementation. SPH in UniverseSandbox will likely be OpenCL only.

[WitheHole18]

WOW Chad the ''film''is fantastico!!

[Josh]

This is amazing! It's clear to me that much work has been done on this, as I can tell from the videos.   
Also, I'm sorry for not posting in quite a while; I've been busy lately with school, friends and whatnot, but I'll try my best to become far more active!

[seanjenkinsjr]

you dont need to add soud fx for the asteroids hitting water you would still here rocks

[seanjenkinsjr]

well you would not here anything really but this would make the game more appealing for kids and young astronomers 

[WitheHole18]

well you would not here anything really but this would make the game more appealing for kids and young astronomers 

yes...
Greenleaf will be added to the SPH Alpha Alpha 7 or 8?
Perhaps it would be better to release the first Alpha 7 so we test and try any bugs, but there is also the hance to do a more complete check with Alpha 8 but that would mean more time...

[Greenleaf]

Greenleaf, will [SPH] be added to the Alpha 7 or 8?
Perhaps it would be better to release the first Alpha 7 so we test and try any bugs, but there is also the hance to do a more complete check with Alpha 8 but that would mean more time...

It will not be in 7 and likely not in 8.
Or, that is only half true. It has been there since alpha 1, I think. Its just not available , since there are issues, which makes it incomplete for testing purposes.

[WitheHole18]

ok thanks 

[crashman1390]

• When you added silicates to Mars, it turned into a star. Is that really accurate? Can you create a star out of sand?

If the body is massive enough and if it can fuse atoms, in theory, yes.

[gabriel.dac]

• When you added silicates to Mars, it turned into a star. Is that really accurate? Can you create a star out of sand?

If the body is massive enough and if it can fuse atoms, in theory, yes.

there is a huge difference between fusing hydrogen and fusing..... SAND

[dechireur77]

• When you added silicates to Mars, it turned into a star. Is that really accurate? Can you create a star out of sand?

If the body is massive enough and if it can fuse atoms, in theory, yes.

there is a huge difference between fusing hydrogen and fusing..... SAND

At the beginning he adds has material to appeal the moon. Then he adds has material to appeal Jupiter. we the planet made he to add the gas of jupiter. It is indeed that?
It is for that that it is to transform into star
At first it adds a material called "moon" (the planet changes its appearance) Then he adds a material called "Jupiter" and it is with this material designated as the planet will turn into a star.

[Xriqxa]

Im really sorry, but I didn't get ANY of that.

Could you explain what you meant by ading the material "Jupiter"?