Short guide to GPU rendering with V-Ray RT

This is an excerpt from the tutorial by Dabarti. You will find full text on dabarti.com.

The aim of this guide is to help with switching to rendering on GPU with V-Ray and has all the basic information needed to better understand advantages and limitations of this approach. Everything below this point is based on our experience with using V-Ray GPU (RT) as our main production renderer.

1. Why GPU for rendering?

It all started around 18 months ago when we decided to do a hardware upgrade to get better 3ds Max viewport performance. So we installed new GPUs (it was GTX970 4GB) and decided to see how things improved with rendering on GPU with V-Ray RT. We loved it!… Well, to be honest not straight away. It took time to change the mindset, but the speed boost and interactivity were there to help and sooth any pain caused by some V-Ray Adv features missing.

It wasn’t the first time I tried rendering on graphic cards. But back when GPUs had 512-1024 MB of memory it wasn’t really a production ready solution (at least for us). It changed with launch of Nvidia’s maxwell cards that came with 4GB on board, did cost fraction of their Quadro brothers and were much faster and more energy-efficient than earlier generation. This alone made it possible to render 70-80% of our scenes.

2. Why V-Ray engine?

We’ve chosen V-Ray RT as our main rendering engine at the end, but It took us some time be convinced. One thing that I feel is a bit unfortunate is that for a very long time I did think that it’s just a gimmick, just ‘real time’ addition to V-Ray Adv, that rarely worked as you would like it to. It didn’t help that at earlier stages there were very big differences in renders from RT and ADV due to many missing features. Shading setup from Adv would often look completely different in RT. It would often crash or run out of memory. But I’m extremely happy that Chaos Group didn’t dismiss GPU rendering as being ‘too hard’ and pushed forward with it. And I believe that now it’s getting very big, it’s something you cannot walk by without admiring.

Looking at V-Ray RT as a completely different engine is the key to loving it. You need to go full throttle with it. Shade, light, render previews, finals with RT. Going back and forth to CPU (Adv) is not the best idea in the same way that jumping between Corona, Octane and V-Ray in the middle of production isn’t. That said, you can still use it for lighting preview and shading, but you have to expect that some features will be missing or may work in a different way.

We had a lot of issues with it early on… Really a lot. But Chaos team made it easy for us by quickly fixing bugs and adding many features. Currently RT is at fully production ready state and to me it has proven to be best way to create good-looking pictures.

Read more: What kind of hardware do you need?, rendering settings, memory management, shading and lighting, rendering animations - you will find full text on dabarti.com.