Szymon,
Here are a few recommendations that would help to convert/render your models into OR (ObjReader)
1- In order to create an OR wavefront material file (.mtl), avoid to assign multiple textures to a single mesh.
2 - Try using the same name for the mesh and the texture.For example rather than a generic "BezierCurve.285" name, use individual "cable_red", "cable_yellow", "cable_green", "cable_blue" for each of the mesh.
3 - Do not use white space in file name.4 - Always put all textures, 3d files (.obj, .fbx, .c4d, etc.), and material file (.mtl) into the same folder.
