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

[voltron7]

you said you turned down reflections. did you also turn off trace reflections in leaf materials?

[glorybound]

Do you mean refraction? I turned the swatch to black

you said you turned down reflections. did you also turn off trace reflections in leaf materials?

[voltron7]

Do you mean refraction? I turned the swatch to black

No, I meant options/trace reflections/un-check
Actually, since you mention it, I'm not sure what impact turning off refractions will have.

[DPS]

What happens if you disable (as a test) the leaf opacity maps in your scene altogether?

[glorybound]

I can try, but with a test scene. I'll report back.

What happens if you disable (as a test) the leaf opacity maps in your scene altogether?

[RockinAkin]

What happens if you disable (as a test) the leaf opacity maps in your scene altogether?

Yep - definitely give this a try. Opacity maps for things like leaves can really slow a render down - especially if that opacity map has any filtering/blurring going on.
See if that gives you a noticeable speed boost. And if possible, change the leaf cards into actual (but simple) leaf shaped geometry and leave it at that.

[glorybound]

They also have translucent maps, too. I'll spend some time next week digging deeper into this.

Yep - definitely give this a try. Opacity maps for things like leaves can really slow a render down - especially if that opacity map has any filtering/blurring going on.
See if that gives you a noticeable speed boost. And if possible, change the leaf cards into actual (but simple) leaf shaped geometry and leave it at that.

[grantwarwick]

It's not always best to rely on material subdivs to reduce render stress.

For example, the AA engine handles geometry noise far better so you don't need as many material samples if there is a lot of noise coming from tree's or displacement etc.

[glorybound]

I am spending some time learning this stuff. I am using the provided scene and I got things pretty optimized. What render times are you seeing? I had to bump things up pretty high to get rid of all noise, in all the elements, and my render time is 15 minutes. I am running across 5 machines, with about 80GB or RAM. The render is 1000 x 600 - for such a small scene the render time is huge, isn't it? The render time mentioned doesn't include pre-pass time.

[glorybound]

Scratch that. I didn't realize that the provided scene was optimized. So, I'll see what I can learn from it. When rendered, it took 4 minutes.

[Jorq1H]

Can you post the sample rate pass? Are you hitting max 32 AA samples anywhere in the image? It seems like heavy overkill as there is no noisy textures.

I wouldn't call this a win yet, look at the specular highlight on the tea pot, its much noisier, during animation this would be a problem.

Jorq1H - While that speed increase is ASTOUNDING... I agree with Morbid Angel that we'd need to fix the noise in the teapot's highlight before calling it a success. But luckily we know there's a TON of room for improving the optimized render given the difference in render times. Even so, that's totally nuts.

I have not been able to go back to this scene yet because of long work hours and the holidays. I will try and experiment with this further on this week. But the sample rate reach does max out at the teapots reflection of the sun. This is something I see only when using hdr maps with very high range i.e. a really intense sun spot. 1/32 was the rate with which I achieved the fastest render with the smallest amount of noise. I can post the sample rate passes later when I get back on my computer.

[Neilg]

They also have translucent maps, too. I'll spend some time next week digging deeper into this.

Remove all translucent maps from leaves. Disable refraction completley & use a 2 sided material for that effect. reflection depth should be at 1 too. There no way trees should affect your render times like that, something is seriously wrong.

[glorybound]

HOLY CRAP! I used the VMC script to change the reflection depth to 1, I removed the create GI, and it chomps right through the trees, bushes, and grass like they were not there. I went from 17hr to 30 minutes, without loss of quality!

Remove all translucent maps from leaves. Disable refraction completley & use a 2 sided material for that effect. reflection depth should be at 1 too. There no way trees should affect your render times like that, something is seriously wrong.

[RockinAkin]

HOLY CRAP! I used the VMC script to change the reflection depth to 1, I removed the create GI, and it chomps right through the trees, bushes, and grass like they were not there. I went from 17hr to 30 minutes, without loss of quality!

Now THAT's more like it.
If you can, post a before/after of the universal settings render, and the optimized one!

[glorybound]

But, my grass that was in the shade, was monotone. I ended up turning back on the GI, which worked and my render times are still low, so it was the reflection depth that increased the speed.