Skinning and or rigging.
Basically you create a mesh with it's arms and legs spread out.
Create a skeleton that matches the one used in the mocap data and match it's position to the mesh.
Generate bone weights for each vertex.
The actual details of how to do each stage vary with your tool chain, it's very different in 3ds max from how you do it in blender, but it general, that's how it works.
Then when you animate the mesh, you position the skeleton, then use the bone weights to position each vertex relative to the bones.
In principle, it's really easy. In practice, a nightmare. I'm not a graphic artist and rigging a character usually ends up with me throwing things at the wall. The usual things, mice, monitors, people... occasionally desks ..