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Oddball Artifact
About Truespace Archives
These pages are a copy of the official truespace forums prior to their removal somewhere around 2011.
They are retained here for archive purposes only.
Oddball Artifact // Work in Progress
Post by spacekdet // Aug 22, 2007, 2:03pm
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spacekdet
Total Posts: 1360
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Ran into this doing some tests.
Scenario: You're looking at a shelled glass hemisphere lit by a shadow-casting Area Light, (min subdiv= .04, max subdiv=1) and a Skylight for fill. The glass is 'speckled' with white pixels, but the really interesting thing is the almost 'sine wave' artifact indicated by the arrow. I think it's showing up just about where the area light would be reflecting if it were visible. Area Light options has 'render geometry' toggled off. No matter what max/min setting I choose for the area light, I keep getting the white pixel artifacts. I know I've run into this problem before, but can't remember the solution... any clues?
8080 |
Post by spacekdet // Aug 23, 2007, 7:35am
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spacekdet
Total Posts: 1360
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Clues?
Beuller?
Anyone?
8091 |
Post by Jack Edwards // Aug 23, 2007, 7:38am
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Jack Edwards
Total Posts: 4062
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It's certainly odd! :confused:
I don't know about the speckled light problem, but graininess with area lights is fixed by upping the density for the Area light.
Try this thread:
http://forums1.caligari.com/truespace/showthread.php?t=3116
-Jack. |
Post by Emma // Aug 23, 2007, 9:26am
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Emma
Total Posts: 344
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hmmm, maybe it's your normal hidden secret copyright watermark you didn't know about yourself so far. :cool: |
Post by 3dpdk // Aug 23, 2007, 5:13pm
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3dpdk
Total Posts: 212
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That's a really strange one. Is this 6.6 or 7.x and Vray?
The only thing that I can tell from the image is that it appears to be a surface thing and not a reflection. Are you using an image based texture? .. or an image based reflectance or alpha map? If you rotate the sphere does the "scratch" rotate, too?
The white speckles almost look like dust on a photo.
Forgive me if this is a 7.x problem and my 6.6 knowledge makes me say dumb things. |
Post by nowherebrain // Aug 24, 2007, 1:31pm
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nowherebrain
Total Posts: 1062
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Yeah, my mouth has the same effect for me:p . |
Post by Steinie // Aug 24, 2007, 1:41pm
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Steinie
Total Posts: 3667
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Spacekdet, quick get 300 lbs of instant mashed potatoes and a 4'x8' piece of plywood and make a mountain in your living room, it's a message!!! |
Post by spacekdet // Aug 24, 2007, 4:47pm
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spacekdet
Total Posts: 1360
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The message, it's a 'sine'!
It's telling me not to make moles into mountains.
Whoops, also should have specified that it's tS6.6 and Lightworks.
Shader for the glass is straight Caligari Phong. On closer inspection, some of the white speckles/pixels were not even on the glass object, so I'm not sure if the artifacting was tied to the reflections or not.
I think after more tweaking it turns out the area light artifacts perhaps were caused by having the size of the area light scaled too small. It was small but also very bright. My background sphere that provided reflections was also textured with a translucent/luminous material that may have been set a little too high. Perhaps it was the combination that did it. I scaled the light larger and toned down the environment and it seems to have smoothed itself out.
The artifact looks oddly mathematic somehow...like the bones of the rendering process were showing thru. |
Post by 3dpdk // Aug 25, 2007, 6:34pm
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3dpdk
Total Posts: 212
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Something I have noticed in a few of my renders is IF an object is transparent or semi-transparent and IF instead of a sky box I try to use a background effects shader image, the transparent object can't figure out how to reflect or refract the image. It'll do weird things to the image including magnify a small part of it.
I also notice little black speckles in the image, also.
It really would be interesting to track this one down.
It looks like someone intentionally scratched a Christmas tree ornament!:)
Paul |
Post by W!ZARD // Aug 26, 2007, 7:40pm
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W!ZARD
Total Posts: 2603
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Congratulations! You've finally captured an image of the ghost in the machine! |
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