Ambient Occlusion Pass

[glorybound]

Hello-

I get these Revit models, that are Frankenstein, and ambient occlusion passes are a nightmare. Is there a way to do an ambient occlusion pass with double sided materials so I don't have to deal with the normal's?

[muoto]

Hmm..with vray2sidemtl ?

[Björn Radler]

You have to render the AO pass via VrayLightMat + Vray dirt and have to turn on 'emit light on backside' in the VrayLightMat

Best regards

Björn


PS: I remember there was a tutorial about this on ronenbekerman.com. Turning off 'emit light on backside' helps to find flipped normals vice versa

[lukx]

How Exactly you guys do AO pass? VrayDirt as material?

[Macrog]

To get AO pass - simply add VrayExtraTex in the Render Element and put there VrayDirtMap (subdivs about 20) - it works for me

[Björn Radler]

Yeah thats right, i usually use ExtraTex too..... but the initial problem in this thread was how to handle models with lots of flipped normals and not how to setup an AO pass in general. Flipped normals appear to render black in this approach.

[sandykoufax]

How about using this script?
http://plugins.angstraum.at/vrayao/index.htm

[glorybound]

yes. this is the issue. I'll try the 2 sided material.

Yeah thats right, i usually use ExtraTex too..... but the initial problem in this thread was how to handle models with lots of flipped normals and not how to setup an AO pass in general. Flipped normals appear to render black in this approach.

[vlado]

Hm, we have a "double-sided" option in the VRayDirt texture, but it doesn't seem to be exposed in the UI. If you need this urgently, please email me to vlado@chaosgroup.com and I can get you a build with this option.

Best regards,
Vlado

[Björn Radler]

Hm, we have a "double-sided" option in the VRayDirt texture, but it doesn't seem to be exposed in the UI. If you need this urgently, please email me to vlado@chaosgroup.com and I can get you a build with this option.

Best regards,
Vlado

Maybe you can hack this in for the next release , would be helpful in some cases

[lukx]

thanks, for plugin tip.

[pixelplume]

Did you happen to try using Mental Ray just for the AO pass? I had the same issues with a Frankensteined Revit model and was running out of time. Out of desperation I tried Mental Ray and seemed to play better with the model even though my skills are very low with that render engine.

[glorybound]

I did use a double sided material, and it worked like a charm.