How to create a transparent material that receives shadows (and maybe reflects a bit too)

Rendering
1

I’m using Neon/Brazil, and trying with advanced material set to fully transparent with a bit of glossy reflection.
The hope is to use a background image which includes a floor, but to add some shadow and reflection from the model geometry. The reflection part seems to work, but I can’t get any useful shadows.
Furthermore, if the floor material has any transparency, the other objects in the scene also become a bit transparent (!) showing the background bitmap.
Anyone got any ideas?

Ta, C

Supplemental:

If I could project the background bitmap onto the floor object from the camera POV , it would not need transparency thus avoiding the weird contagious transparency effect. Seem to remember view-based mapping projection from somewhere… was that from 3DMax? Would be nice to have in Rhino.

2

I would try using the Brazil Matte material.

3

Click the texture in a material and choose ‘screen’ in the mapping section.

4

Thanks Brian, ‘screen’ mapping works well, but still having some issues:
If the floor object has any texture map at all, the other objects in the scene become semi transparent.
Also happens with Brazil Matte material with no texture map… odd and annoying.

5

Here’s a sample that’s as good as I can get it at the moment using Neon and Brazil. I used a BAM for the glossy reflections and controlled the opacity with a gradient texture so you get some of the shadows. The tricky part is that the environment also needs to be a planar version of the same image used as the background for the Neon display. Otherwise you get transparency to a default environment color of gray.

Brazil_Neon_GlossyMatte.3dm (1.8 MB)

6

Thanks Brian… haven’t signed in here for a while. I’ll have a play with that.