Facing ratio/fresnel from other camera

[bigbossfr]

Hi all,
I have a question : how can i get facing ratio from a custom camera (not from the render camera) with Vray (and a stable build) ?

Thank you.

[vlado]

V-Ray doesn't measure the facing ratio with respect to any camera; it is determined by the direction of the ray hitting a surface (so that it works correctly in reflections etc).

However, since the facing ratio is simply the dot product between the surface normal and the ray direction, you might be able to get what you need with a few samplerInfo nodes wired with some plus/minus/divide nodes.

Best regards,
Vlado

[bigbossfr]

Hi Vlado,
Can you give me an example scene ?

I use a pointMatrixMult node, but it doesn't work on Vray.
So, if you can show me how you do this just with a samplerInfo, plus/minus node/vectorProduct, etc etc.... it will be very great (all controled by a camera position).
My brain is dead.

Thank you.

[bigbossfr]

I can get what i want, but it looks like my facing ratio have a "low intensity" (it is not black and white).