I’m working on the candles for a partially candle lit scene. It seems to me that the SSS shader is not responsive to increasing samples.
Here are 3 renders,
256 samples (1 min 3 second)
512 samples (2 min 2 second)
1024 samples (4 min 1 second)
They all look like crap, the transition between the SSS and the glossy shader is a pandora’s box of ugliness.
Why is this so bad? See below for render settings and node setup. Rendered with a Nvidia GTX 770.
subsurface can be pretty finicky, usually (in my tests at least) you need 2000+ samples before it starts to look right, but even then you can get some color banding.
Here are two images, the first uses SSS, and the second, a simple volume setup, both rendered at 24 samples.
While not as accurate, you can see that for the same render sampling, you can get close to the result you want using volumes instead of the SSS. You just need to be careful with your nodes when adding a surface for reflectivity, making sure there is transparency for the light to shine through.
This is an interesting idea. It seems that cycles just doesn’t do SSS well. I’ve gone as high as 10k samples with this and still do not have a clean image.
Try lowering the strength of your light source, and increasing the radius of the sss. Also try clamping indirect at 2.
2000 samples is usually enough.
SSS works best with Branched Path-Tracing, not regular Path Tracing. Set the SSS samples higher in BPT settings and you’ll get cleaner results.
Path-Tracing (64 samples, 8 seconds):
Branched Path Tracing (20 AA samples + 7 SSS samples, 8 seconds):
As you can see, Branched Path Tracing is vastly cleaner for SSS.
I will second what William said, for hair and SSS you should really be looking at branched path tracing I think you could also drop some of your bounces down
