Tips on how to get Cycles rendering nice and smooth?

I am making a motorcycle model in Cycles and I want it to be nice and smooth… but even when I crank up the samples to 1000 + turn its still very noisy. What do I need to do to get Cycles renders close in quality to Blender Renders?

Make sure you aren’t using Add shaders, make sure nothing is reflecting back more then 80% of the incoming light, make sure you have your bounces set to a reasonable level, make sure you are using large light sources, etc. Without uploading a .blend or at least some pictures of your settings, it’s going to be hard to give you a solid answer.

On top of those comments ^^^, I would also check “no caustics” in the render tab. I find that makes a huge difference in how long it takes to clear the scene up, and is rarely needed.

Beyond that, your lighting setup can also make a big difference. Small, very bright lights with a lot of things to bounce off of can take a very long time to clean up, while larger lights in open environments clean up instantly.

There’s also some stuff on the blender wiki about reducing noise. They are some GREAT suggestions. There are two things that helped me a lot.

  1. Make sure your white values do not exceed the max visible (255 I think). Add shaders will definitely go above the max, but there are other ways to also blow out the whites. You can use the clamp option to make sure this doesn’t happen (again, look at the wiki entry about reducing noise)
  2. I’ve had a LOT of trouble with HDR lighting. Yes, it can look great but it causes so much noise. I’ve found that it’s easier to just stay away from HDR and set up manual lights - which is too bad because it looks great.

I didn’t even think of “no caustics” because I usually tweak bounces after switching to the “limited GI” preset and it checks it automatically.

As for HDR lighting, I’ve found the exact opposite. Mine normally clear up incredibly fast compared to manual lighting. Are you setting “sample as lamp” in the settings? Maybe try increasing the MIS map size?

Thanks guys

I just had to turn up my # of samples

Still though what does a lot of this stuff mean… I turned caustics off, but what does it do exactly? Etc.

caustics are bands of light caused by focused reflection and refraction of light beams. Think of the pattern you see on the bottom of a swimming pool or in the shadow of a glass of water. They are very hard for a unidirectional path tracer to solve, and thus take many MANY samples to clear up. In most cases it is simply not worth it to use them, especially if you’re doing animation.