Ambient Occlusion Render Element noise level

[pixelsim]

Hi there

In the help docs for the Ambient occlusion render element it says: Note: Noisy or grainy images can be smoothed out by increasing the Occlusion Rays channel. Same as using the Modo renderer.
If I change the Occlusion rays in the render output to reduce noise the AO output is the same.
Its the same if I change to to 2048 or 8 or 16, or anything. The render output never changes.

Am I doing this wrong and there is another place to change the Occlusion rays?
Or is it broken in Vray? Using the Modo renderer the Occlusion rays effect the AO output noise as expected

thanks
Simon

[vladimir.nedev]

This was broken when the Use Local Subdivs option was introduced. If you enable it, the Occlusion Rays will start working. But don't do that, as it's not the recommended workflow and will create other problems.

Instead, I will add a new V-Ray Subdivs per AA sample which will work per-AA sample (i.e. it will specify the number of samples per one AA sample) and won't be affected by the value of Use Local Subdivs.
I will make the same change to the V-Ray Dirt texture.
This is how Vlado did it for V-Ray for 3ds Max, and it was later ported to Maya, so it seems to be the correct way to do it.

Note that because the new subdivs are per AA sample, you need values that are very low. The default value will be 3 and is optimal when you consider the max AA samples are 24, the default.
You can increase it slightly (4,5) to get rid of noise in the AO render element, but anything more can be dangerous since it will slow down any areas which require a lot of AA samples.

Greetings,
Vladimir Nedev

[pixelsim]

Hi,
That's great to hear!

I am continually happy with my Vray purchase, and the level of support you give for the plugin is fantastic, so thank you again Vladimir!!

Cheers
Simon

[vladimir.nedev]

The nightly build from 2017.08.29 will have the new options.
Attaching screen-shots of the new UI.

Greetings,
Vladimir Nedev

[pixelsim]

Thats great!

Thanks for the fast update

Simon