We wanted to integrate the Maxwell material into XSI as closely as possible, but the plug-in API is too limited. We have been talking to Softimage about this and hopefully the API will improve in a future version of XSI. This concerns both the ability to edit the materials inside XSI and see their textures in the viewport.
This is how native materials are translated:
Lambert - exported as a diffuse material:
- "Lambertian" layer
- XSI color -> reflectance 0
- XSI transparency -> transmittance
- white reflectance 90
- roughness 100 (lambert)
- XSI index of refraction -> Nd
- bump map if the XSI material has one
Phong - exported using a template for a plastic material:
- layer blend mode set to "additive"
- "Lambertian" layer:
- weight 100
- roughness 100
- XSI color -> reflectance 0
- XSI transparency -> transmittance
- white reflectance 90
- XSI index of refraction -> Nd
- bump map if the XSI material has one
- "Glossy" layer
- the luminance of the XSI specular color -> layer weight (scaled to the 0..100 range)
- XSI color -> reflectance 0
- XSI transparency -> transmittance
- XSI specular decay -> clamped to 100, inverted and set as layer roughness
- XSI index of refraction -> Nd
- bump map if the XSI material has one
Blinn - exported using a template for a metal material:
- layer blend mode set to "normal"
- "Lambertian" layer:
- weight 20
- roughness 90
- XSI color -> reflectance 0 and reflectance 90
- XSI transparency -> transmittance
- XSI index of refraction -> Nd
- bump map if the XSI material has one
- "Shiny" layer
- the luminance of the XSI specular color -> layer weight (scaled to the 0..100 range)
- XSI color -> reflectance 0 and reflectance 90
- XSI transparency -> transmittance
- XSI roughness -> layer roughness (scaled to the 0..100 interval)
- XSI index of refraction -> Nd
- bump map if the XSI material has one
The plug-in detects if the nodes use bump maps or normal maps and exports the materials accordingly.
If the index of refraction is left at the default of 1, the plug-in forces the value to 2.5, since 1 is used as a special value by the Maxwell engine.
When transparency maps are exported, the "invert" checkbox is taken into account.