I'm sure this has been asked a million times, but can someone point me to resources about optimizing renders? I get that sometimes it's just a fact of life that a render is going to take a bit, but I know so little about what all these settings do for cycles that it feels fairly opaque.
Right now I'm staring at a 5.5 hr render (with my admittedly out of date GPU), which isn't a big deal because it's just a still, but it makes it a little difficult to iterate.
Hi Ian ttechnicolorwildlife ,
That is a good question, but almost impossible to answer.
It highly depends on the scene you are rendering (among other things).
If your GPU is so outdated, that you might as well render with CPU, you can enable Path Guiding (helps mostly with interior scenes).
Further, don't get too overwhelmed by all the Settings; here are the 'most important' ones you can focus on:
Noise Treshold is what used to be called Adaptive Sampling and means that if the difference (per Pixel!) is less than that value, it stops rendering (that Pixel).
Setting a Time Limit might be useful (0 sec disables it).
Reducing the Light Bounces will usually reduce Render time as well.
What I used to do a lot, with my old computer, was too use Render Region (CTRL+B when in Camera View) to experiment with optimizing Render times.
You will probably not get your Render times from 5,5 hours down to half an hour or so.
There are some Denoisers you could try. Blenders own Denoisers, Super Image Denoiser (free) and some more that I haven't tried.
I'm not using Denoising myself, but their quality has improved a lot. Also for test Renders it can be very useful.
Yeah I agree with Martin, there's only a handful of important settings to tweak. The thing to have in mind is that if you are trying to get render times down, you are most likely making tradeoffs, usually it's: less time rendering = lower final quality. More time rendering = better final quality. There is a point where you can shoot too many samples and the render is already very clean and you're just wasting time. So you need to make tests, with parts of the render as Martin says, to see how many samples is enough until your image is clean. After that you can decide what to do, if you sacrifice some noise here and there or less light bounces but then you have less global illumination, trade this for this, etc, in order to shave some render time.
Thanks! This all gives me some direction for the future at least. I know I'll need to invest in my system eventually!