BEPUphysics

I'm just tossing this out there; have you tried other, non-Y directions? Momentum along Y would simply give the box an instantaneous up or down boost (if negative, down) and would be difficult to tell apart from gravity.

The linear momentum field is a direct reference, and is affected by gravity, so if gravity is working, the internal handling of linear momentum should not be the issue.

Good luck (and thanks for trying the engine out)!

I working on my Third person camera when I start thinking on something ? I don't how hard it would be to implement a sort of box container ? And another question pops into my mind. Which of this method would cost less, using the future mesh based collision (maybe using a simpler mesh that the one display) or a bunch of boxes for a simple level ? I'm planning to make two different game so my needs aren't the same.

cheers

Generally if your geometry can be represented multiple entity types easily (boxes, cones, etc), a StaticGroup will end up having less entity management to do and thus have a performance benefit over the only-triangle StaticTriangleGroup. The StaticGroup uses internal partitioning as well, it just handles it slightly differently.