09-12-2012, 06:55 PM
In my experience, you need to adjust the materials' specular properties. For whatever reason, many of the DAEs I've downloaded from here have their materials' specular color set as white, at least when imported into Blender. For me at least, textures still render; they're just really pale. Changing the specular color to black or reducing the specular intensity to 0 should make them render as expected. I'm assuming you were referring to rendering the models, not viewing them in the 3D view.