Hello guys, I have a sphere that I use as a background for my render in Mantra. I am using an environment light with an HDRI texture as a source of lighting. My problem is that my background blocks the light from reaching my geometry.
I have tried using Light Mask and the Light Linker but without success.

Any ideas?

Thanks a lot

Maybe try adding -shadow to the Render Visibility section. That will prevent the sphere from casting shadows.

Makes total sense now!! Thank you very much BrianHanke

When I place another light that I linked to my background only, I see that it illuminates my other geo, the rays are probably bouncing back on my geo. How can I avoid this and have this second light only affect my background and not indirectly illuminates anything else?

Thank you very much

anbt
When I place another light that I linked to my background only, I see that it illuminates my other geo, the rays are probably bouncing back on my geo. How can I avoid this and have this second light only affect my background and not indirectly illuminates anything else?

Thank you very much

You can probably find what you need by playing with the Light Mask and Render Visibility options. For example, setting Render Visibility to "Invisible to secondary rays" might prevent the bounced light you're talking about. You can also remove a light's contribution to an object by adding it to the Light Mask.

Thanks for your answer. It weirdly works better when I set it with 'invisible to diffuse ray' than with 'invisible to secondary rays'. But if I bump the intensity of the light whose diffuse/secondary rays I do not want to see, then it doesn't work.

In the end, it works more or less if I keep my light at a low intensity.