A new (BodyNode) property was recently added in Physion.
Its name: Gravity Scale (gravityScale).
As the name suggests, the gravityScale property of a body can be used to "scale" the gravitational attraction applied to it.
In other words, the gravityScale allows you to specify a different gravity for each body.
By default, the value of this new property is 1.0 meaning that the Scene's gravity will be applied to the body.
If you change this value to say 0.5 then only half of the Scene's gravitational force will be applied to the body.
If you want to make a body float (i.e ignore gravity) you can set a gravity scale of 0.
To make a balloon-like body you can set its gravityScale to a negative number.
In the video below you can see the gravity scale in action:
Note that the minimum value of this property is -1 and its maximum value is +1.
Using this new property and some minimal scripting, the user can easily create gravity pads which are very useful in marble races and other similar simulations.