Hotspots taking forever to render...

[sebbiej]

Hi guys,

I'm working on an interior shot, and the majority of it renders pretty quick, but I'm having trouble with some bright reflections that seem to take forever to render!

The scene has got some small windows that have area lights outside of them, that simulate daylight (Basic light settings: Intensity at 45, 128 subdivs, Not using skylight portal). And where these windows appear in the reflections of some shiny objects (chrome, shiny plastics) (with glossiness at 0.99), the buckets just take a very long time to render.

The sample rate pass appears mostly blue/green, and the red patches are where these hotspots are.

I've got the Image sampler set to Adaptive DMC, no filter (I read that it's best not to use one?),
Min Subdivs as 1, and Max Subdivs as 36.
Threshold at 0.04 for test renders.

Any chance of some help?

I'm not using any kind of global illumination (As much as I'd love to, it takes too long to calculate due to a lack of render farm here! ).

Any help is gratefully received! Thank you!

[georgi.zhekov]

Hello,

Is it possible for you to send us a sample scene for investigation so we can see where the problem is?

Thank you,

[sebbiej]

Sorry, I cant, the project is under a Non Disclosure agreement!

[ivaylo.ivanov]

Well, then you must find and manage the huge light intensity your light sources produce. VRay 3.0 has an option to clamp such rays, which is not physically correct, but is the quickest fix:

http://docs.chaosgroup.com/display/V...Global+Options

[sebbiej]

Thank you for the replies!

I'm still using Vray 2.4 at the moment, but I've clamped the output level at 4 (I think that would be about ok?), and I'll take down the intensity of my area lights, hopefully that should help.

[vlado]

You also need to turn on "subpixel mapping" for that to work.

Best regards,
Vlado

[sebbiej]

Yeah thank you Vlado, I had that on already, just to get rid of the random hot speckles that appear in renders.

Clamping the max output level, taking the light intensity down, and using subpixel mapping has worked. Thanks very much all! Still learning, but getting there!