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View Full Version : occlusion pass - wh'appen?

markw7
03-27-2005, 10:57 PM
I rendered out the left image a month and a half ago and can't seem to recreate it. All my latest tests look like the one on the right.

http://atomic-content.com/temp/kccc1_3_dirt.jpg

1. The left is a standard example of an occlusion pass, correct?
2. How the &%*$ did I make it and what am I missing???

I believe in both cases I followed these steps described by Aneks...
http://www.cgtalk.com/showpost.php?p=1804391&postcount=11
from this thread...
http://www.cgtalk.com/showthread.php?t=145844

On the other hand, perhaps that's my problem, ie. the right image is what one would expect from the steps outlined above and the left image was a result of a completely different method.

My brain is apparently too small to retain any lighting and rendering expertise.
Jozvex
03-27-2005, 11:11 PM
Your left hand image looks more like regular diffuse lighting that's been multiplied by an occlusion pass. The one on the right looks like an occlusion pass, only the distance the rays are spreading is way too short.
markw7
03-28-2005, 06:48 AM
Thanks Jozvex. I was actually going to email you directly if the title didn't catch your eye. You're the man with the answers on all things dirt it seems. Now I got to figure out how I made image one cause I'm in love with the look. Maybe I comped it? Keerist I'm lame.

PS It would be really cool if someone who looked like Sarah Michelle Geller knew all about shaders.
joie
03-28-2005, 09:06 AM
The problem there is the spread of the rays, may be you´ve changed the settings of your scene and now is measured in milimeters instead of kilometers (LOL).

Seriouslym I think the problem could be you rendered the first one with Dirtmap and the second with the AO solution that comes with MAYA wich works a little diferent...
markw7
03-28-2005, 06:05 PM
Ah, it's quite possible I changed the scale settings. The whole units/scale/grid settings is another issue for me -- I want to build using real world units but shaders are often effected adversely, or so it seems. So the spread of rays... all I've got to do is up it from the default 88 (not in front of maya at the moment, just guessing) to something like 880?
Jozvex
03-29-2005, 01:19 AM
No not that value, the clipping one. Like max distance or something. Hehe sorry I'm not at Maya so I can't see what it's called.

And now that I look at your images a second time, that's definitely all the problem is. There's no diffuse lighting on the left, the max distance/clipping is just way larger than on the right and so there's much more grey.
markw7
04-30-2005, 11:21 PM
You rock Jozvex for pointing me in the right direction. I guess that was exactly the problem. Here's the current version with adjustments, which to me looks much more like a standard dirtmap than even the first one I posted...

http://atomic-content.com/temp/kccc1_4_dirt.jpg

scale! :thumbsup:
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