vray RT 3.3 ambient occlusion pass

[kimgar]

I'm testing vray rt 3.3 for quick AO passes, but so far i can't seem to get any clean/fast results.
It feels like i've been tweaking everything up/down but not really getting anywhere, has anyone successfully done this for animation?

[super gnu]

are you using vrayambientlight? or vraylightmtl? or vrayextratex?


what is the issue? ive done lots of ao passes for animation. imho vryadirt still isnt as nice looking or fast as the mental ray ao shader..

[kimgar]

i am using extratex with vraydirt bumped to 256 subdivs and still get really noisy output.

i have not tried ambient light or lightmtl yet, but these also rely on vraydirt iirc, so it shouldn't make any difference?

[super gnu]

have you got "consider for aa" enabled for the extratex? if so im not sure why it would be noisy.. anyway if you are using 3.3 the subdivs shouldnt affect anything.. its controlled by same colour thresh. and max aa as everythng else.

[kimgar]

consider for AA is enabled for extratex, and i've been looking for sampler or AA settings in RT, but all i can find under "image sampler (antialiasing)" rolldown is render mask and image filter. And closest i can get to colour threshold is the Max. noise setting in "V-Ray RT" rolldown...am I missing something here?

[super gnu]

i apologise.. i missed the bit where you said you were using RT.

max noise is basically the equivalent of colour threshold. you want that on a nice number like 0.005 for a clean render. and just in case you are new to RT, you need to disable the 1 minute time limit it has at default, by setting it to 0.


if your main render is already clean and your extratex is still noisy in this case, im not sure. afaik "consider for aa" is supposed to fix these kind of problems.

maybe there is a bug.

[kimgar]

i apologise.. i missed the bit where you said you were using RT.

haha, been there, done that

max time and path are set to 0.0 and max noise is 0.001. I would have thought this setup would cause the render to go on almost forever, but it skips to next frame after 30 secs

i'm not sure i understand how RT sampling works

[vlado]

The RT only adapts to the RGB color channel, so if you want to use it for AO passes, best to use a self-illuminated material override with the VRayDirt texture in the material, instead of a render element.

Best regards,
Vlado

[kimgar]

Ah! I see, it works fine now, thanks Vlado!