Background image too dark

V-Ray V-Ray Common Public
1

Hello,

I am making the transition from Vray 2.0 to 3.6.

I am mapping a bitmap texture in the background as a screen. When I render the rendered bipmap it’s slightly darker than the actual picture im mapping. When I use Vray 2.0 to fix this I would go into the options editor > colour mapping > uncheck affect background. This would result in the background being rendered exactly as the jpeg I was mapping. However, I can find this setting in Vray 3.6???

I understand that I can increase the background multiplier from 1 to a higher number. This lightens the image however it’s too difficult to get the exact brightness as the jpeg I’m mapping in the background.

I understand that in the Vray frame buffer I can add a background image. When I do this the background image turns out exact however this is not an option because in the scene i’m rendering I will be using the wrapper material with matte setting turned on and this wrapper material setting doesn’t work when the background image is placed via the vray frame buffer.

Please tell me how to get the background image the exact same brightness/darkness when mapped as a screen in the environment background??

Thanks for your help

2

bgg.jpg
bgg.jpg720×906 79.2 KB
Bg .jpg
Bg .jpg1914×1038 369 KB
3541.jpg
3541.jpg1500×919 159 KB

background image rendered not the same as jpeg im mapping

3

Hello,
You can save your V-Ray Settings as a .vropt file (Chaos Docs) then open the file in any text editor. Find SettingsColorMapping and a few lines below “affect_background”. Edit its corresponding value from 1 to 0, save the file, and then load it back into V-Ray.
Alternatively, simply increase the Background intensity until you get a satisfying result (try high values - 10, 30..).

We will revisit this particular option and discuss its place in the V-Ray UI.

Kind regards,
Peter

4

In Mental Ray the background images are totally unaffected by the lighting of the scene. Many clients give me photos to work with and to put my renderings in. So it would be very fine to have an option to leave background unaffected and to show it in the renderings as it is, without the hints mentioned above!

5

Thank you for your feedback! It is now logged as part of our internal discussion notes. Let me know if you have any other requests.

Kind regards,
Peter