Gravity 6 simulates planets orbiting stars, moons orbiting planets and stars orbiting stars and all of the action can take place in 3D.
As a result you need to be able to create objects to populate the universes you create. At a minimum this would require specifying mass, position and velocity. Bells and whistles include the object's name, size, color or bitmap, and spin rate, axis and phase. Additionally, as an observer in your universe you can specify where you are, which direction you are looking in, which way is up. Finally, in order to make sense of doing something like zooming your view in on something, you need to specify how far along your line of sight you are looking.
Gravity 6 has a point and click or point and drag interface with some sensible defaults for object creation and for creating stable orbits. You can optionally drill down and specify any of the above details numerically allowing the modelling of precise situations should you so wish.
The screen shot at your right depicts an imaginary model where the Earth is orbiting Saturn.
The program comes with around 20 tutorial models. Including real ones, such as our Solar System.
