Glass making environment too dark

V-Ray V-Ray for 3ds Max General
1

I am rendering an animation and therefore - for simplicity - I need to be able to render the glass in scene.

I am using a nice panoramic sky bitmap in my environment slot. When I render without the glass, the environment looks correct. When I unhide the glass and render, the environment looks far too dark.

I am sure this is a simple thing that I am missing, but I have really started to confuse myself with not knowing what needs to be checked.

Any tips?

2

if you’re working in Linear Space, maybe you have to set the Gamma for the Env-Map accordingly.
hope this helps.

ale

3

So you’re saying that in an interior animation, when looking outside, without glass, the environment map appears correct, but with glass it looks too dark?

Is your environment refraction override turned on? Are you changing the the color mapping or vrayphysical camera exposure settings when the glass is on? Material refraction and fog color? Sorry, these are basic things I’m sure you’ve checked…

I don’t think its a gamma issue, because that wouldn’t cause a difference when looking through glass or not.

4

I am doing test renders for an animation.
When the glass isn’t there and I render, the env looks fine.
When the glass is there and I hit render, the env is dark.
Glass is simple: diffuse is black, reflect is white with fresnel, diffuse is white
If I put the env bitmap on a large sphere, it renders just fine if the glass is there.

Must be something to do with env maps I guess.

5

You are using a VrayPhysicalCamera? Did you uncheck the Affect Background in your Color mapping rollout? That will cause this exact problem. If unchecked, the environment image is not affected by the vray camera exposure settings, and renders the same as if you rendered a perspective view. But when viewed through refracted glass, you are seeing the affect of the exposure settings.

If Affect background is checked they will be equally dark. Multiply the background image until it looks correct (For an HDRI image with default vray camera settings and LWF, I start with a multiplier of 30 in 1.5 sp1).