I like to open up 'Our Solar System' (quick shortcut is Ctrl+2) and then use the move tool on the orbiting planets to shape new orbits.
- It's also fun to adjust the orbital elements (sma, ecc, inc, peri...).
- Try this: click and drag up or down in a textbox to shift the numbers without typing.
Improved Accuracy
And when you're looking at the projected orbit of a moon or planet, press Shift+S to turn on the more accurate calculation mode called RK4 (from the original Euler method). Pause the sim, hover over a planet, and toggle this on and off. You can see the path shift from decaying spirals (wrong) to full ovals (right).
Eventually the plan is to make the RK4 mode the default mode (and call it something else).
Also... currently dust still uses Euler even if RK4 is turned on.