Hey @Abstract,
The discussion here is related: Stop Sliding down Slopes (SSS)
“However I am forced to use BoxImpostor as the MeshImpostor only works on other sphere meshes.”
Does a cylinder impostor not work?
“if I walk my players mesh against a wall, it will bounce back and fall over like a box. I would like to keep my players mesh always upright and standing like a person.”
I might try to add an scene.onBeforeRenderObservable and update you player to the desired orientation every frame but I havn’t investigated too much into getting something like this to work before.
Another option is to try avoiding a physics engine for the player and use the simpler collision logic Babylon provides: https://playground.babylonjs.com/#U8MEB0#0