I came across a video and an article about optimizing vray renders.
Both use 3DS max but the concepts translate to VRAYforC4D.
They are both very useful and the end result will be better quality and faster renders. The link at the bottom of the quoted article leads back to the original post.
The video is a free sample from Grant Warwick’s course called Mastering VRAY. I have not purchased this course and I am not , in any way, affiliated with it but this free sample is very helpful.
V-RAY RENDER OPTIMIZATION
AN IN-DEPTH TUTORIAL ON OPTIMIZING V-RAY TO DELIVER THE
HIGHEST QUALITY RENDERS WITH THE FASTEST RENDER TIMES. v1.2 – FEBRUARY 2014
This tutorial attempts to cover and clarify the process of optimizing your V-Ray render settings to get the best possible render quality and fastest render time for a given scene.
There’s often a lot of confusion surrounding the topic of V-Ray’s sampling and what ‘ideal’ settings are. Many times you’ll see artists adopt the ‘Universal V-Ray Settings’ of having the Image Sampler (Anti-Aliasing, or AA) Max Subdivs value set very high (like 50 or 100), and then simply lowering the noise threshold value until the render becomes clean enough – thinking that it’s the best / fastest that V-Ray can do. But with a bit of understanding of how V-Ray works under the hood, you can achieve a higher quality result WITH faster render times – in some extreme cases ranging between 3x faster to 13x faster than the universal settings.
We’ll first cover some of the underlying concepts behind how rendering and V-Ray’s sampling works. Then we’ll go over an example scene to demonstrate exactly how a render can be optimized to be faster and cleaner. Then we’ll learn how to identify the different sources of noise a scene can have. And finally I’ll provide a step-by-step procedure to optimize any scene to render with an ideal balance of quality and speed.
If you already know the underlying concepts and just want the technical step-by-step procedure, click here to skip right to it.