There is no correct way to make collision objects for the Torque engine. It all depends on how your programmer wants to implement collision detection. Several games used this engine and they all used different collision schemes. Different collision schemes can be different for different shapes as well. Some shapes use simple sphere collision that is derived from the bounding box, some have custom-built collision shapes. Vehicles tend to have custom collision shapes.
Custom collision shapes can be created by assigning a negative detail number to the shape and creating a corresponding detail marker. Shapes with negative numbers will export but not draw. Because Maya does not allow dashes ("-") in object names, underscores ("_") must be used.
The Torque Game Engine presently uses detail markers named Collision_# with the mesh shapes named Col_#. The shapes must be convex hulls (no concave surfaces).
Here are some of the naming conventions:
Collision_1 through Collision_9: These are collision markers.
Col_1 through Col_9: These are the actual collision meshes.
LOS_9 through LOS_15: Markers for line of sight, or "bullet", collision shapes.
LOScol_9 through LOScol_15: Geometry for line of sight collision.
Keep the detail meshes as low in polygon count as possible, because collision can be processor intensive. Vehicles are limited to ONE collision mesh for the collision shape.