M | Model Element (T+ Model) | A Three Plus Model, Mesh, or Brep
Rm | Roughness Map (Bitmap) | The green channel of this texture is used to alter the roughness of the material. (A System Drawing Bitmap or full file path to an image.)
R | Roughness (Number) | How rough the material appears. 0.0 means a smooth mirror reflection, 1.0 means fully diffuse. 0-1.0
M | Model Element (T+ Model) | The updated Three Plus Model Element
