3 questions

[Daniele]

first: Why glass material (black color, total fresnel reflection, white refraction, 1 cm of width) look too much dark (nothing change with a diffuse white color) and change too much (because of refraction) the objects beside (expecially with two or three glass one ove the other in the image) (ior 1.52) ?

second: Why with extruded objects the vray displacement often get some face of the object darker than the others? for example: I have a spline, I extrude that, apply vraydisplacement, render, and... some faces are much more darker... If I don't extrude but I just make an 'Edit Mesh' all work fine!

third: (Sorry...) How can I put an Image in this post????

[flipside]

1) color of your glass depends both on reflection and refraction. So if you have a dark environment, this will reflect in your glass and causes it to be darker.

2) no idea

3) you need your own webspace to upload your image to, and then use the [img][/img] tags to include your image in your post (url of image goes in between the two tags)

[GoncaloP]

I think that glass have no diffuse color, so its better to keep it black in this way you will avoid to calculate the irradiance map for glass...

Gonçalo

[Daniele]

Well, I'm sure that the glass color the reflection color, but the problem is when I have two glass one over the other (an open glass door, a glass cube that cross a glass wall, for example). Also with a bright background the result portion of the image where the two glass are showed one the other is alway dark.

[egz]

Daniele: sounds like you are exceeding the max refraction depth. Try to increase the refraction depth value in the glass material, and also make sure the global override isn't set to some low value.

[Daniele]

I've already tried with the refraction depth, but nothing change (or change a very little bit, except for render time...).
What is global override ?

[DP]

look in your render dialogue for the global panel

[Daniele]

Right, I already use global override (both for reflection and skylight, to fine tune background, GI and reflections, but is not here the problem.

I solved the problem using a standard material with vray map reflection for the 2nd glass. It took a bit more longer to calculate but work fine!