V-Ray Render Optimization - an in-depth Guide (call for Before/Afters)

[RockinAkin]

VRay Render Optimization



http://www.CGGallery.com/tutorials/vray_optimization/

There can often be 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) 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 nearly 3x faster than the universal settings can give you.

This article is designed to be an essential, step-by-step guide on how to Optimize any render in V-Ray.


I've tried my best to make the information as simple and clear as possible for a complex topic like this - but there's always room for improvement.
So I'm sharing it here first with the V-Ray community for a bit of feedback and discussion. Take a look, try it out, share your findings, and please let me know if you have any feedback!
I'm also planning on adding some production Before/Afters to the article later this week, so if you can, share your Before/After images!

Hope it helps - Happy Rendering!

[cheerioboy]

Akin, a great write up. Thanks for sharing! We can't have enough ways explaining this process, and I think the more people chiming in the clearer it starts to become. Thanks again

[joconnell]

Bastard, beat me to it

Great guide and well done for all the contributions over the past while, they've really helped clear things up a lot!

[zeronove]

thanks a lot for taking your time to make this guide, well done

Could you please elaborate a this tip: "unlinking the Image Sampler's Color Threshold value from the DMC Sampler's Noise Threshold and increasing it in small increments to help the Image Sampler not confuse DMC Noise for geometric or textural detail"

IMHO this thread is going to explode in a few days

[RockinAkin]

John! The more the merrier! I'd LOVE to read what you're cooking up too - maybe then the word will finally get out. I credited you in the tutorial - thanks for the knowledge you've shared!

[RockinAkin]

Could you please elaborate a this tip: "unlinking the Image Sampler's Color Threshold value from the DMC Sampler's Noise Threshold and increasing it in small increments to help the Image Sampler not confuse DMC Noise for geometric or textural detail"

Sure - I've updated the tutorial to make it a little more clear... but it's done by unchecking the 'Use DMC Sampler Threshold' checkbox, which allows you to adjust the Image Sampler's Color Threshold value independently from the DMC Sampler's Noise Threshold value. Hope that makes sense.

[cheerioboy]

Sure - I've updated the tutorial to make it a little more clear... but it's done by unchecking the 'Use DMC Sampler Threshold' checkbox, which allows you to adjust the Image Sampler's Color Threshold value independently from the DMC Sampler's Noise Threshold value. Hope that makes sense.

So I take it that after you've successfully balanced a scene, if you're working with a single or separate noise thresholds, you would shift them both higher if you needed faster renders? So that becomes the sole throttle for speed vs quality.

[jdrouse]

Rockin tutorial man. I'm going to put some of my complex scenes thru these optimizations and will report back on successes! Great write up! I think it'll change the game for some people and half my artists!

[grantwarwick]

Nice work man and thanks for sharing it.
It's going to help a lot of guys on here.

[JezUK]

Wow

Fantastic tutorial and information Akin, thank you so much.

And it seems perfect timing as it goes so well with the great training currently being offered by Grant as well.

So, big kudos to you Akin - you're helping me get to grips with what is under the hood of VRay

One question......

Seeing as the SampleRate pass is so important (and I only learnt about this render pass a week ago) - is it possible to switch off the rendering ('beauty') pass during its creation ? In other words is it possible to render which ever passes you want (in this case the Samplerate pass) without creating a Render Image ? (since at these early stages, the Samplerate, reflection, GI passes are where the important information is).

Thanks

[grantwarwick]

Tick the "Show Samples Button" (removed in 3.0)

[vlado]

Tick the "Show Samples Button" (removed in 3.0)

Keep in mind that The "Show samples" option does not save any calculations; V-Ray still calculates the RGB pass normally, it just doesn't show it.

Best regards,
Vlado

[grantwarwick]

I've never actually compared render times with it so I probably should have stated that haha.

[RockinAkin]

So I take it that after you've successfully balanced a scene, if you're working with a single or separate noise thresholds, you would shift them both higher if you needed faster renders? So that becomes the sole throttle for speed vs quality.

Right - just remember though, as you lower the AA's color threshold it'll introduce more red pixels into your SampleRate, so you'll probably have to raise the Image Sampler (AA) values, which in turn means you'll have to adjust the scene's subdivisions as well (since the new higher AA value will be dividing the number of secondary samples more). :P

Nice work man and thanks for sharing it.
It's going to help a lot of guys on here.

Cheers man! Your video did a great job covering the procedure as well!

Seeing as the SampleRate pass is so important (and I only learnt about this render pass a week ago) - is it possible to switch off the rendering ('beauty') pass during its creation ? In other words is it possible to render which ever passes you want (in this case the Samplerate pass) without creating a Render Image ? (since at these early stages, the Samplerate, reflection, GI passes are where the important information is).

As vlado pointed out - no, you cant have a SampleRate pass without actually rendering an image. This is why in the procedure listed in the tutorial, we turn almost everything else off in the scene so we can tune the Image Sampler (AA) quickly without having to wait for everything in the scene to calculate.


Great seeing the positive responses so far! I hope it's clear and easy to understand to those new to the topic! Please let me know if not!

[stef.thomas]

Thanks for taking the time to write this, a great reference to come back to. Can I ask, should you always do your testing at the full resolution you are planning to render at?

Also, just a thought, but might be worth mentioning the importance of getting a smooth noise-free light cache solution first before looking at DMC settings.