Try setting CameraClsColor to white (or anything other than black) or use a solid white texture image and see if the object shows up. I suspect the problem is that the model is being textured pure black. In that case the UVs probably aren't being exported correctly from your modeling tool. I'm not familiar with LightRay; how exactly are you getting from that to b3d file format? And what procedure exactly are you doing to texture the model? A common beginner mistake is to use some sort of built-in material setting without actually setting UV coordinates. This would look fine in your modeling tool but no UV coordinates are being exported since none were ever assigned.