VRayMtl Refraction doesnt seem correct to me. What is the logic?

[djx]

I've noticed that if I have an open mesh, a half sphere with a vRatMtl for example. I place a light behind the sphere and put the sphere between the light and the camera. If I increase the refraction color I would expect the surface to gradually become transparent and refract the things behind it, but what actually happens is that as soon as the refraction color is not black (0.001 for example) the surface lights up brightly as if it is fully translucent.

If I do the same thing with a closed surface it behaves as I would expect, so I'm not sure if I'm misunderstanding something about shading open surfaces in vray or if this is a bug.

thanks

[Reaversword]

Till i know, Vray needs closed surfaces for refract the rays, I supposse if you want do something like a contact lens, for thin it be, you need to do it closed.

[vlado]

I've noticed that if I have an open mesh, a half sphere with a vRatMtl for example. I place a light behind the sphere and put the sphere between the light and the camera. If I increase the refraction color I would expect the surface to gradually become transparent and refract the things behind it

This is how it works for me, and how it should work. Can you post that part of your scene or email it to vraymaya@chaosgroup.com so that we can take a look?

Best regards,
Vlado

[djx]

Here's two cubes scaled to be like a thin sheet of glass. The one on the right has the face closest to the camera removed. The spotlight is on the far side pointing back towards the camera. Both cubes have the same shader, and the refraction color value is stamped on the images.





The surface on the right just seems a bit strange to me.

refraction_001.zip