What is Bullet Physics?
“Bullet” is just the name of the Physics engine,. ...My bad… :(
It was developed some time ago for a game, “Hitman”
anyway.. the physics engine has been developed further, and the code was made available (Free), so programmers started to use it in 3D software,. like Blender….and now Carrara.
so, it’s the code which handles the physics in carrara.
When you add the point force, it has a positive value,.. which pulls everything into that point, like a black hole.
so, a negative value will do the opposite,.. and it will force everything away from that point.
in your scene, you have the point force at -100 at frame 0,. then at frame 30 another key as the same value.
it could be that you’ve moved the point force slightly at frame 30 and that created the key-frame..
but, if you want to have the force start a t frame 30,.. set the frame 0 value to 0,. then select the Tweener (the area between two key-frames) and change it to “discreet” instead of linear .
The “Discreet” tweener will hold the value of the first key-frame ,. until it reaches the next key-frame, so it’s a sharp change, like a switch off and on,..