I constantly have spotty problems when rendering.

wildbillnash

Most times in poorly lit renders, or dark or shiny hair, or whatever, I have spots all over the place. I'm getting tired of going into Photoshop to correct the problems. Any ideas what's going on?

I included crops of two pics, the left side in filament, the right side in iray. What are those white spots?

Richard Haseltine

If it's poorly lit Iray will take a long time to reach a final value for each pixel - some will be bright from being hit by paths from strong light, some will be dark through having been hit only by paths hitting dark areas, and some may not be hit at all. Adding more lights to reach into the inacessinle areas and then adjusting Tone Mapping to get back to the desired look is the only real fix, other than waiting a long time.

wildbillnash

The longer I wait the more spots I get. I'll try adding more lights for the objects that have that problem and see what happens. BTW, the two images are from an outdoor scene with a daylight skydome. Not sure how much brighter it can get with that.

 

Richard Haseltine

In that case it could be too much glossiness, I was thrown by your reference to poorly lit renders. I have had to turn down one or more glossiness settings to tame hot-spots in various products.

Pitmatic

Now I might be wrong BUT if you have shiny things in your scene they reflect the light or the lack of it from everywhere in your scene all 360 degress of it. so if using just scene lighting you can have probelems whereas a HDRI will light and refect into every creviceif that makes sense.

dijitul

I've seen similar issues (but usually black spots) that appear late in a render when the Environment Map or Environment Intensity render values are set to zero and certain iray surface parameters are also set to zero (I believe some thin wall settings were the culprit).  My work around was to instead set the Environment Map to a black image and leave the intensity/map settings to default.  Not sure if this is your same situation, though.  There's also the Firefly filter in the render settings which ought to be always On.  Hope one of these help you.  If not, it may be helpful to include screen shots of both your render settings and problem surface settings.

 

wildbillnash

Lighting seems to be the issue with creating the fireflies. In low lighting any dark surfaces will get spotty. I guess I either have to use brighter surfaces or brighter lighting.