www.kraytracing.com

Can anyone help me with this? I have blotches on either side of the image and I have no idea what to do to get rid of them.

The scene is for the First Floor stair lobby of a new Primary School and is lit by a spotlight for the sun with several area lights in the fittings.

My settings are:-

Photon mapping with irradiance caching
Area lights computed separately
Light mapping 600k photons received, N=800

Precahche steps 3, Autophotons low 20%, high 80%

Precache dist 50%, Precache blur 400%, Photons multiplier 2

FG rays 50 min, 600 max, threshold 0.0001
FG distance min 20%, dist max 300%
FG angle tolerance 20deg, spatial tolerance 0.1, B/D 10%

Rays Min 10, Rays max 60, GI resolution 1m

Tailer- recurse 10;prerender 1,2,0.1;gradients_neighbour 0.1;limitdr -1;

I confess to only having a very slight understanding of the render settings. I read all the posts and tips, and try to learn from other people's setups. It gets me results, but occasionally I get problems like this.

If anyone has any suggestions, I would be really grateful.

Can you show the precomputed unfiltered render please? I suspect you're not receiving enough photons on those parts.

Here it is, I can't see a particular problem, but then I'm no expert

Hmm it doesn't look like there is photon problem.
But you can try increase autophotons steps to 4 or more. Also render without materials, just a white version so we can see error better (you can use override color).

Actually I'm not sure how to use the override colour feature. It doesn't work quite the same way for me. I have e-mailed GT about it.

You just enable it and choose a color... Anyways you can make all your surfaces gray or some light color and will get the same effect.

Oh it looks like this thread was locked again accidentally...

Sorry for the delay, Grzegorz needs to make some changes before I can use the colour override. I'm sure it won't be long though.