VrayLightMat...

[Giovanni]

Hi all,
I have been doing some searching on vraylightmat, and it is my understanding that Vlado&co are implementing a better mesh light type, which is cool.

However, I want to make sure there is still need for a better vraylightmat, since some of us use geometry and materials assignments done outside max (for example, models from Revit).

So, I still think we need to be able to turn a mesh into a light emitter by assigning a vray material...please?

On the subject, as of right now, I read that to increase the quality of vraylightmat you should up the hemi subdivisions, and lower the samples, but that makes a lot of splothces...Turning the subs to 100 and incresing the samples to 30 made a decent image, although far from final.

What else can we do to improve the quality of vraylightmat? I understand it is a GI based light source, so if I am using IRRmap+QMC should I up the settings for the QMC GI as well?

Thank you

regards

gio

[sv]

you can put a VrayLight or a series or VrayLight's set in portal (skylight) mode around the object.
Vray will then understand better where to trace the light info from and you'll get really nice (spoltchless) renders.

Am i right ppl?

[DaForce]

Vralightmat's are often rather splotch and increasing the IR maps is what you need to do. Lowering the clr thres to like 0.3 should help abit as wel, althought I wouldnt go any lower your rendertimes will start to suck.

Also the advice that sv gave is spot on, exactly how Vlado demonstrated in a thread last year.

[sv]

just to note, even high Irradiance maps still have problems, i've found the only thing that can really make a big difference is using skylight portals around the object, otherwise you get this:

Top image - VrayLightMaterial Only with High Irradiance Map + QMC Gi.
Bottom image - VrayLightMaterial with a series of VrayLights set to skylight portal mode around the hanging plus; Irradiance Map lowered to Medium and LightCache used for speed as the quality is controlled by the VrayLights, not only th GI solution.

When you adjust the exposure on the .exr images, you can see the really poor sampling compared to the really good sampling:

VrayMaterial Only :



With Skylight Portals for directions:

[alexthg]

nice example!

as the skylight portal setup, did you use 6 vraylight planes around the lamp?
Or can we use only 1 vraylight sphere, with radius set just outside the lamp boundary?

[sv]

i used 6 planes around the lamp.
actually, it was more like 30 due to the shape of the plus, not sure about the sphere - give it a try, i'd be interested to know the results, as doing 30 did slow down the Irradiance map calculations a lot.

[alexthg]

just did a quick test

found out that vraylight-sphere with skylight portal ON behaves just like ordinary vraylight-sphere (i.e when you increase the light multiplier, the scene is brighter...).

maybe anyone else can confirm this?

[vlado]

Yep, the portals really only work for rectangle lights.

Best regards,
Vlado