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•FAQ• Unexpected stribes in render

Posted: Tue Sep 12, 2006 11:34 am
by jalokin
Anybody can tell my why i get these stribes in my image?


Image

Posted: Tue Sep 12, 2006 11:40 am
by Pierre Caron
let it render longer and it should disappear

Posted: Tue Sep 12, 2006 11:50 am
by rivoli
are you using any grayscale map?

Posted: Tue Sep 12, 2006 12:33 pm
by jalokin
let it render longer and it should disappear
- it's around sl 10 so i dont think that time would solve the problem

are you using any grayscale map?
I am not really sure what a greyscale map is but the material is just a flat white lambetian surface. No textures or anything else[/quote]

Posted: Tue Sep 12, 2006 2:21 pm
by glypticmax
When I get those striations, they usually disappear between SL 12 and SL 14.
I usually get them when using a bump map or other texture. It seems flukey.

Posted: Tue Sep 12, 2006 2:50 pm
by jalokin
glypticmax,


I will try to let it run to sl 14.

Posted: Tue Sep 12, 2006 2:57 pm
by tom
May I have the scene for checking, thanks.

Posted: Tue Sep 12, 2006 3:41 pm
by rivoli
jalokin wrote: I am not really sure what a greyscale map is but the material is just a flat white lambetian surface. No textures or anything else
this is what I meat by greyscale:
http://en.wikipedia.org/wiki/Grayscale
I thought that you were using either a bump or roughness map, which are often greyscale images. maxwell needs textures in rgb though, and those kind of weird effects may happen because of a greyscale map.

Posted: Tue Sep 12, 2006 5:32 pm
by jalokin
Just had it running to sl 14 and no change

Posted: Tue Sep 12, 2006 6:03 pm
by glypticmax
If you're not using a grayscale bitmap, you may have bumped (no pun intended) into something unusual.
I would take Tom up on his offer to look at the file.

Posted: Tue Sep 12, 2006 7:39 pm
by jalokin
glypticmax thanks for your comments.

I did indeed take the offer from Tom.

Posted: Wed Sep 13, 2006 12:32 am
by jalokin
When i use physical sky instead of sky dome the striation disappears. will test again with some different sky setups.

Posted: Wed Sep 13, 2006 12:53 am
by tom
Hi Jalokin,

I'm not sure if it's related to physical sky or skydome but these moire patterns are due to projection from excessive amount of spherically oriented surfaces of an emitter. In other words, I just replaced your massive-poly spherical emitter with a simple sphere. It's more efficient with no more patterns. I e-mailed the scene back as well.

Image

:idea: You should avoid using complex geometry for emitters. Especially if they are highly symmetric objects (like most primitives) and if they are already not directly seen. When you don't really need the precision in their look. Sufficient illumination needs less detailed emitters than we usually used to make models.

Best regards,
Tom

Posted: Wed Sep 13, 2006 1:32 am
by glypticmax
So the problem was in multi-poly emitters?

Posted: Wed Sep 13, 2006 8:55 am
by jalokin
Hi Tom,

Thanks a lot for your help.

when is a sphere complex?