How does Blender (Bullet) mathematically calculates the coll

[jormollo]

Good morning,

I am working with Blender and the collision detection. I have read in many places that Blender uses Bullet to calculates the rigid body translations, rotations and collisions but I have not found a detailed physic/mathematical explanation of how it is numerically solved.

Could you redirect me to some manual which explain it in detail (physics, meshes, boundary conditions, etc.)?

Thanks in advance.

[Basroil]

Can't tell you how mesh collisions work, but the other types are functionally equivalent to the bullet collision shapes and should be solved the same way. The mesh-mesh stuff might be gimpact like in the moving concave demo, but haven't looked into the blender code and it could be an entirely custom solution. Their modifiers stack and time variant frame sizes can cause issues (since collision shape, mass, and inertia all can change from one frame to the next), so the only way to know for sure is to go into the code yourself .

As for bullet itself, there's a nice theoretical paper in the download page that explains the theory behind bullet.

[jormollo]

Thank you for your answer, I have been looking in the download page of bulletphysics but I don't find any paper...

Could you tell me please which paper are you making reference?