Mottled looking materials with Irradiance Map

[Streetwise]

I've got an image that I'm working on where there are several areas that look really mottled in areas that should be pretty plane looking. I tried switching to Brute Force for the primary and that looks like it fixed the issues, but the renders then become a lot more grainy looking and excruciatingly slow! I also replaced the affected area material (ie. wall paint) with a very basic VRay material and diffuse color. Still no luck.

Any suggestions for getting rid of the mottling look while maintaining decent render times would be appreciated. Thanks!


VRay Preset.zip

[Morne]

Stick your irradiance map on medium preset and raise Interp Samples to 50 and see how that looks? This scene looks pretty simple, you should be able to switch off retrace threshold in lc (although I have mine set to 0.5 on most scenes)

Do you have skylight portals in the windows?

For Brute Force there's a bunch of other things you should do to get it clean and lower render time. There's more to it than just increasing BF samples.

This scene on your site looks pretty clean, why don't you just use the same settings again?

[Streetwise]

I tried what you suggested. Definitely better, but still not right on the walls (see attached) The walls are the standard AEC Extended walls, so I'm sure they're not flipped around or something weird like that. I will say that the render times dropped pretty dramatically. What was a half hour, is not under 5 minutes, so that's good. I have about 200 frames to do.

There are skylight portals in the window with a VRay Sun. I'm also using a VRay Dome with an HDRI map in it as my ambient light source. I tried disabling the dome and added a VRay plane light for fill light instead. The wall issue was a little less severe and my render times improved by about 30%. I did put the Interp samples to 50 and lowered the Raytrace Threshold to .5, from 1.0. So that's where I'm at right now. Almost there, but not quite.

[3DMK]

Yes you almost have it right! You just need more irradiance map samples due to the fact it is an internal scene which is more difficult to get a clean and smooth GI. On interior scenes I often go as high as 180-240 subdivisions. This is fine for an architectural animation as you don't have to recompute the GI every frame. I would also increase your Light cache to 2000 to make sure it's not splotchy as well.
Cheers
Jamie

[Streetwise]

Thanks Jamie. Here's the latest... Still not right around the picture on the wall, but really close. The wall above the hutch looks great! For IR, I used the medium preset (should I use "medium animation"?) and set HSph. to 240 and Interp. samples to 50. Then I upped Light Cache Subdivs from 1000 to 2000. I turned off Retrace threshold. Prefilter is set at 100 using "nearest" and 10 Interp. samples. The only error I see is the one about using light cache for glossy rays. That is checked at the moment.

The render time is about 14min. which is certainly doable, but was hoping for something quicker. My Noise Threshold is at .005, (.85 Adaptive amount), so I may try using .006 or something to see what that does.

Anything else I should try to clean it up more?

Dave

[Streetwise]

An update: I decided to go with Brute Force for the primary, and turned the LC up to 2000. This is giving me pretty clean output with no visible mottling. The render times are 12min/frame. So I'm okay with that. Still not sure what to think about the mottling issues. I've done quite a few interiors and have never run into that before. Thanks for the help!

Dave

[Vizioen]

An update: I decided to go with Brute Force for the primary, and turned the LC up to 2000. This is giving me pretty clean output with no visible mottling. The render times are 12min/frame. So I'm okay with that. Still not sure what to think about the mottling issues. I've done quite a few interiors and have never run into that before. Thanks for the help!

Dave

[ATTACH=CONFIG]19499[/ATTACH]

Maybe check your render elements (GI, lighting, reflection,...) to see where this weirdness came from