I’m trying to export my scenes to BMRT and Lightflow, but the scripts won’t export textures or even colour of materials.
Do I have to manually reassign materials or something ? 
:o
Don’t know of BMRT, but Lightflow should work… for PLAIN materials, for materials with name extension ->go to the README of the exporter<- and for Image Textures.
Procedural and built in textures are not exported AFAIK
Regards
Stefano