dull mountain
I have a car RigidBody3D that I need to have accurate collision around the open windows so I used trimesh collision sibling/ConcavePolygonShape3D. I see this warning that it shouldn't be used on anything buy static objects and the car will be moving. But I started up the scene and everything works as expected.
¯_(ツ)_/¯
What problems should I expect to run into because of this warning? Or am I in the clear baring unforeseen circumstances?
Cheers!
native wind
it is a stable for most physics engines that concave shapes are bad for anything that is not static. They regularly create missed collision when you least expect it and they have bad performance in general. They are disjointed convex sets of shapes internally so really hard to calculate. They would require horrendously bad and high cost algorithms to avoid most of their issues.
So instead of doing all this extra to allow a few users bad practices most physics engines do not support them or add a warning that you are playing with your luck using them.
like instead of using a single concave shape it is nearly always better to split that shape into simpler convex shapes when it is used for a rigid, moving body.
bold vortex
I have already encountered this collision problem. This works if the object with concave collision shape collides with another object with convex collision shape. On the other hand, if it encounters a concave shape, detection by the physics engine will fail.
dull mountain
Thanks @native wind @bold vortex! I have a moving car RigidBody3D and need the windows to not be blocked by collision. All the other collision settings draw collision over the windows. How can I create a collision shape that doesn't have collision over the window?