Need Help on Glazing

[crushdrive]

Hello there, need help on my in progress rendering of our exterior perspective

im having problem on my glazings some of the glazing have Black areas.

I've used different methods in modeling like 3dface & 3dsolids on them as

shown on the attached file. The following are my queries:

 

1. How do i solve rectify the black areas.

2. Does 3DSolids is better on rendering/modeling rather than 3Dface?

3. What does these dark areas causing them? material?

 

Looking forward for your much needed help. Thank you.

 

"Crush"

[Tommy L]

Black areas looks like coplanar faces.

The main difference between giving your glass a thickness or just one face is refract value. When light passes thru 1 face, it bends. When it passes thru the other (back) face, it straightens up.