M | Model Element (T+ Model) | A Three Plus Model, Mesh, or Brep
Tm | Transmission Map (Bitmap) | The red channel of this texture is multiplied against .transmission, for per-pixel control over optical transparency. (A System Drawing Bitmap or full file path to an image.)
T | Transmission (Number) | The effect factor between 0-1.0.
I | IOR (Number) | Index-of-refraction for non-metallic materials, from 1.0-2.333. Default is 1.5.
R | Refraction Ratio (Number) | The index of refraction (IOR) of air (approximately 1) divided by the index of refraction of the material from 0-1.0.
M | Model Element (T+ Model) | The updated Three Plus Model Element
