Weird vraylight problem

[rikou]

Weird problem

I've got two Vraylight (instance - just "Affect diffuse" and "Invisible").
I precal' my Ir+lc for my walk-through.

As you can see, I have this artefact just for one Vraylight.
I don't know what it is, I don't understand why it's happen just for one (as they are instanced)
max2012+Vray 2.50


It seems to be from my IR only

[rikou]

Please...Anyone ? any suggestions ?

[tashko.zashev]

Hi,

Have you changed any of the following parameters: Max Transp. levels ; Transp. cutoff ; Secondary rays bias;
Would it be possible to send us the scene file to our support mail or post it here?

[rikou]

maybe secondary rays biais.. because I saw that it was at 0 and I always have to 0.001 (by default for me).
I don't remember if I changed it before or after my precal' IR.
If I changed it after my precal', it could be the reason why I have that dark area corresponding to my Vraylight ?
Not easy to send you the scene (I'm on deadline)

[tsvetan.geshev]

Hello,

After using higher values for Max Transp. levels do you see the black sport?
Do you have this visible in the alpha?
Which version of V-Ray do you use?

[rikou]

I cant check it now but is the Max.Transp. can have something to do with a (invisible) vraylight ? Is it because this Vraylight is behind glass ?
I'll try ASAP

[rikou]

Ok, I doesn"t change anything.... Max.Transp. from 50 to 500, nothing change

[super gnu]

id delete the light, make a new one, you could try just making an entirely new light, forget the instancing if its an emergency. try moving it a bit, away from the cieling etc. could just be "one of those things" thats fixed by redoing it.

also, do you have "affect reflections and refractions" enabled on the light? dunno why this would be an issue on just one of an instanced set though.. but anyway, try turning it off, if its on.

i hate stupid problems with a deadline looming.

last resort: delete the light. wont make such a big diffrerence by the look of things. you could make another light nearby larger to compensate, or put another light in a more hidden position to fill any dark areas... hell you could even use an omni if you were stuck..

or use a piece of geometry with a lightmtl on. works well with high-detail imaps. youd have issues with gi shadowing from the geometry (even if its invisible to camera etc) if its too close to the cieling though.

finally, are you 100% sure its the light? no double faces in the cieling there?

[rikou]

thanks super gnu... In fact, I decided to do in another way... I replaced my (rectangle) geometries with Vraylightmtl by real vraylight and delete the two big one (set invisible and yes, the only thing they have was "affect diffuse")
As you said ! "i hate stupid problems with a deadline looming." !
Thanks again

[super gnu]

ah, so they were geometry with lightmtl, NOT vraylights?

in this case, was the problem one closer to the cieling than the others? cos geometry with lightmtl on still casts shadows from the gi light in the scene. this can be very noticeable on the cieling above light emitting planes. the closer to the cieling, the more defined the shadow.

only way i know to reduce it is to use a 2 sided material on the plane, with a fully transparent material on the back face. but this doesnt fix it completely.

i have no idea however, why, if you had other instances in similar positions, that was the only one causing problems.

anyway, glad you found a fix in the end!

[rikou]

no in fact, the little rectangles you see are geometry with vraylightmat (no GI) just to simulate some light but I had two vraylight.. one of them was the problem

[rikou]

Do I have to avoid Vraylight with "Skylight Portal" AND "Simple" when I precal' my LC and my IR ?
It seems to be a problem, it looks like it add light every frame I precal', then at the end, I have a weird result...

[tsvetan.geshev]

This should not operate this way, as you know "Simple" tells the VRayLight that there is nothing of interest behind the light itself, and so the environment color can be used directly. So it sounds like a bug.
Can you reproduce it with simple scene and send it to us?

[rikou]

sorry !! In fact, it's all my fault... some tricky geometry, more sample for LC and IR and it's all right now...
Thanks

[tsvetan.geshev]

Thank you for the update.