Thanks for the prompt reply.
I don't know about the ashade layer, it's in dwg file I received also.

Actually, I have one more question.
Is there a way in Sketchup or in the Vray plugin, that you can make the background as an alpha channel? I want to load the alpha channel easily in Photoshop to change to a sky image or gradient blue.

Thanks in advance.

I tried to apply material for all of the objects under this current layer. But only certain objects get applied, why?
This is a dwg file I received that I imported to SketchUp.

How come all of the objects in this layer are grouped? Do I have to explode them?

I attached this skp file.

Thanks in advance.

sketchup 7 file