Lights appearing black in occlusion pass.

[heni30]

Hi,

 

Lights that are near the ceiling are coming out black in

my occlusion pass. Any way to avoid this?

 

Thanks,

[Stephen Thomas]

How are you doing your AO pass, vray dirt? Also are you using a vray light material on your lights in this pass? If so try checking the 'emit on back side' box in your light material preferences.

[heni30]

Yes, using vray dirt.

 

I'm doing this for the 1st time so I'm not sure what to do for the lights.

 

I didn't change anything for the lights - just my regular vray plane lights.

 

If I do "emit on back side" won't they burn out the ceiling since they are a couple of inches from it? In this case it's not important because you only see a small strip of it in a uniform tone but if it was a 2 story space showing light coves and tone changes at the wall lines I would need it to not be burned out.

 

Thanks,

[Stephen Thomas]

Ahh, I thought your lights were geometry rather than plane lights. Can't you just hide them?

[erickdt]

Check invisible on your VRay lights. If you're using an over-ride material that is a VRay light material it will cause VRay lights to display as black unless the inivisible option is checked.

 

E

[heni30]

Yup,

 

For override material OFF if I hide lights and uncheck hidden lights in global, the lights are off in the rendering.

 

For the occlusion pass with the same set up but with override material ON

everything came out fine.

 

Is this always the case?

[heni30]

So using a light material for the material overirde becomes the ONLY light source for the occlusion pass?

 

Because deleting all the vray lights from the scene and rendering produces the same result.

[erickdt]

I wouldn't delete them I'd just check the "invisible" box in the Vray light modifier panel...

 

E

[dpcaltdcah]

try turning on "force back face culling' under global switches.

[Stephen Thomas]

An occlusion pass doesn't have any lighting in it anyway, it just shows up where objects are touching one another. By far the easiest way to do an occlusion pass is to use the VrayExtraTex render element. Just add it then drop a vray dirt map into it, you can vary the settings by dragging it over to your material editor. Then it is just done at render time without the need to render twice.

[heni30]

Thanks for your help y'all (from Atlanta )

 

Final attached heavily photoshopped (portal, all metal finishes etc.)

[raq007]

Thanks for your help y'all (from Atlanta )

 

Final attached heavily photoshopped (portal, all metal finishes etc.)

 

did u use spot lights in ur ceilings light? if so then i would say its not looking good there..

 

An occlusion pass doesn't have any lighting in it anyway, it just shows up where objects are touching one another. By far the easiest way to do an occlusion pass is to use the VrayExtraTex render element. Just add it then drop a vray dirt map into it, you can vary the settings by dragging it over to your material editor. Then it is just done at render time without the need to render twice.

 

sound nice, can u make a tutorial on it? or u know any specific tutorial on this method?

 

btw friend of mine gave me this link and i found it very easy and useful..

http://scottdewoody.com/tutorial_occ.html

even i use Vray for render.