Vraylight Material porblem

very simple scene just for clarification

source light and 2 boxes plus vrayenvironment fog

1st image a vraylight plane with texture and affect diffuse : 70 ( to get that fog effect without increasing the multiplier too much because it overburns the texture )

2nd image trying to get same effect using vray light material using same texture ( direct illumination on )

since their is no affect diffuse option in the vray light material i cant get similar result
when i increase the light material multiplier too much the texture overburns

is their a way to achieve this using vray light material ?


anyone can help please ?

Do you think you can post that scene? I’m not exactly sure how you have set up things. Is there a specific reason you have to use a VRayLightMtl material instead of a VRayLight?

Best regards,
Vlado

I prefer using it mainly for showing texture in viewport to see what am doing
also vray lights has limitation in terms of shape
vray light material is so much flexible i could add it and map it anywhere on any kind of complex model or even part of it
blend it with other textures/ materials etc

here is the file
hope you can help me out
thanks in advance
light material test.zip (392 KB)

There isn’t a way to achieve the effect with the VRayLightMtl since it does not have that type of control as VRayLights. If shape is something of importance - use VRayMeshLights.

You could use VrayLightMtl as the visible box and put your Vray Light in front of it set to `invisible` to create the fog so you can control each value in case of burnout ?

@hermit.crab thats really unfortunate

@anthonyh that is a solution for simple cases i think
but a complex case where texture is animated along complex model would be impossible

The VRayAtmosphere RE and the SelfIllumination RE should help you achieve what you want in post, without much trouble.
You may need to create a few multi-matte REs to mask out the specific parts of a complex multi-material with lightselects on intricate geo, but if not the two layers will get you most of the way.
Unless i have misunderstood you.

@_Lele multiple problems here
that would be very hard to test before rendering final and i think would produce enormous noise that almost cant be fixed due to lack of information in dark pixels

Also if by any chance the fog is reflected/refracted on a surface that would be very hard to fix in post and will look very unrealistic

As a side note i tried increasing the generate gi value in the object’s vray properties but that didnt affect the fog in any way which i didn’t understand why

Isn’t it supposed to affect it ?

Ok, so the setup is as follows:
VrayLightMtl with texture, set intensity as it’s pleasing to the eye (let’s say, 1.0).
That lightMtl becomes the child of a MtlWrapper, for which you set the GI generation multiplier to whatever works for the fog (say, 30).
Assign the mtlWrapper to the multi-sub slot, or the node you want to turn into a light, not the lightMtl.
Tick “scatter GI” in the environmentFog.

@_Lele thanks alot man never though of that
That solved the problem perfectly

@_Lele i can confirm this workaround doesn’t work with vray next gpu

Mh, pity.
Could you write to support, ideally with a tiny sample scene set up attached (so it’s quicker for them to find the issue.)?