Artifacts / Splotches - VRay 2.0 for Maya 2012

[Emcs07]

Hello everyone,

I am completely new to VRay and I am having some difficulty rendering a shot properly. There are a ton of artifacts / splotches on the lamp and a bit on the wall. I've checked the normals and all of the objects and they seem to be going outwards just fine. This is for a competition due in 1 week, so any help you can provide is really appreciated!

Anyhow, here is the shot and the settings:




This is for an animation so avoiding the noise is really important.

Thanks and best regards,

Eduardo

[Emcs07]

Bumping, still stumped by this issue.

[RobPhoboS]

Typical answer for this kind of thing:

Check on - Subpixel mapping
& - Clamping (maybe around 4)

http://www.spot3d.com/vray/help/maya...lormapping.htm

See if that helps to start with.
Also seems like a very long render time for that image (of course machine dependant) but I think you may need to do some tweaking perhaps.

[Emcs07]

Thanks, I'll try that tonight.

[RobPhoboS]

Just one more thing to always try when you get problems with artefacts.
Save another version (you know for testing etc) and apply a simple vray material to all of the models. Then see what's happening, sometimes artefacts can be materials rather than a specific render setting as such.


(also you can use that scene to start reducing render times and experiment with it)

[TobyM]

Rendering an extra GI, Lighting and a Reflection RenderElement lets you check where the artifacts come from. Since you can view GI, Direct Light and Reflections seperatly.

I notice you have "use lightcache for glossy rays" checked, so it might be a good idea to check "use retrace threshold" and leave the threshold at 1.0.

Do you really need the caustics? If so, they are often a reason for lots of artifacts.

Greetings
Toby

[Emcs07]

Hello,

I did as Toby suggested, I think the caustics are the problem. On the caustics pass I can see it splotching all around. What's the best way to fix this? I would like to keep the caustics, as I like the effect they have with some of the materials in the scene (mostly the eyes).

Regards,

Eduardo

[TobyM]

As you wrote this is for a competion and you have little time left, I would really suggest to set the caustics aside. The only option to get rid of the caustic-artefacts is tweaking - a lot.
They are something you can bother with when you got your GI settings right and have a flicker free animation. Disable caustics for now, get the rest of your settings right, then switch caustics back on and see what you can do before time is up.

Caustics are something for the little extra thrill when you get bored of the other, ordinary GI settings One step at a time young yedi.

[Emcs07]

As you wrote this is for a competion and you have little time left, I would really suggest to set the caustics aside. The only option to get rid of the caustic-artefacts is tweaking - a lot.
They are something you can bother with when you got your GI settings right and have a flicker free animation. Disable caustics for now, get the rest of your settings right, then switch caustics back on and see what you can do before time is up.

Caustics are something for the little extra thrill when you get bored of the other, ordinary GI settings One step at a time young yedi.

Well I "fixed" (huge render times) the caustics with the max photons setting. I think I'll follow your Jedi-master advice and leave caustics for another day. Only thing left right now is the images look a bit grainy, but adjusting the Adaptive DMC threshold should fix it.

Regards,

Eduardo

[RobPhoboS]

Don't forget to post up your results