@fleabay
Hey, Yes I'm using bullet, the moving platforms and moving thins over them is handled manually. firstly the platforms doesn't moves based on velocity, each simulation step I literally change the position of the platform. Before moving the platform finds all objects that are on top of it (using bullet manifolds) and moves the object that are on top of the platform as well.

Also, are you using inheritance, EC or ECS? kind of a mix of both, it look more like COM objects, I have a base Actor Object, which could provide interfaces (which could be inherited or composited, up the programmer). Examples are RigidBody, 3DModel, ParticleSystem, Health

EDIT: Sorry for the late reply, but notification don't always work for me, I'm full with notifications I do not care about so I never watched them.