Vray Mesh Light - Random scatter of face mapped textures

[yp]

Hi,

 

a common practice to scatter light textures of lit windows in architectural visualization ist to use planes with VrayLightMtl in a Multi/Sub material and a MaterialByElement modifier.

 

Works good and can even be improved by some features for randomizing saturation / brightness values eg. with Multitexture map.

 

Actually I'd like to use a Vray Mesh light for this as it seems to have a better quality output and more control over the lights.

 

Somehow I'm stuck with getting the randomization to work..

 

The object's modifier stack is built the same way as it would be for a normal Multi/Sub material light solution - with a Mesh Light set on top. UV mapping mode set to face in my case. Face IDs are kept in the Mesh Light, at least it seems like as I can still select poly faces and see the IDs in the edit poly below the Vray Light in the stack. Actually MaterialByElement modifier can be stacked upon a Vray Mesh Light, too.

 

Multi/Sub material is no option here as it has to be a map which is plugged into the mesh light's texture slot. VrayMultiSubTex CAN be used but the result is not working.

It always shows the first usable VrayMultiSubTex slot (I did assign only clear colors to make it more visible for testing purpose) - if I switch off channel 1 it uses channel 2 only and no further channels. Material ID seems not to be used at all..

 

So, sorry for a confusing description, to cut things short:

 

HOW would I randomize a light texture distribution in a Vray Mesh Light as single set up light are hard to change..

 

 

Any guess?

 

I have the feeling it's just not possible... yet. :/