Vray Light /Affect alpha

[simmsimaging]

I'm not sure why, but the trick i had been using to have my image-mapped Vray Lights invisible to alpha isn't working.

I use and RGB multiply, put an image in the first slot, and a Vray colour with alpha set to 0 in the second slot. I tick "map2" for alpha and drop it into the light. I'm pretty sure that is how it always worked before - has something changed or am I forgetting something?

Is it possible to eventually just add an option to the light to not affect alpha?

Thanks!
b

[simmsimaging]

* I should clarify: the RGB multiply trick does affect the alpha still, but it also knocks out the light in the RGB render as well - which is not what it used to do, unless I'm really mistaken.

If I am - what I want is a Vray light that is visible to camera etc, but not affecting my alpha. Is there another way?

Thanks /b

[vlado]

The VRayColor texture should be white in color - the default is medium grey.

Best regards,
Vlado

[simmsimaging]

I had it as white - it didn't make a difference to the alpha issue, just made my light darker. Here are some screens showing how the light goes semi-transparent when I zero out the alpha contribution, and some screens of the shader setup. Did I miss something?

alpha at 1, colour white



Alpha 0, colour white

[simmsimaging]

Hey Vlado - any thoughts on this? It works the same in RT and Vray (those are RT renders posted)

b

[simmsimaging]

bump. Any chance you had a moment to look at this Vlado?

b

[vlado]

I was not able to reproduce this in my tests; if you can get me a scene where this happens it will be very helpful.

Best regards,
Vlado

[simmsimaging]

Hi Vlado -
I had sent a scene a while ago - were you able to figure this out? I'm still not having any luck using the RGB Multiply approach to remove Vray Dome lights from my alphas.

Is there any chance of just adding a 'do not affect alpha' option at some point?

b

[vlado]

I think I found out where the difference comes from, but I can't remember it right now... I'll have to check it out again

Best regards,
Vlado

[simmsimaging]

Thanks - let me know if you need the scene again.

b