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Rendering of specific ior data

Posted: Tue Mar 06, 2007 12:21 pm
by lllab
hi all,

i am trying to make a golden perforated fassade, and use a layered material with weightmaps.

one layer is a ghost map, and the other a basic layer with ior file, both have the same weightmap, one of it inverted.

the material works very well when not using ior. with ior it looks absolutly wierd where the transparency shows the physical sky behind.

in the preview scene all looks good.

does this setup not work with physical sky? is this a known thing? and if yes is it solved for 1.2?

cheers
&thanks for help!
Stefan

Posted: Tue Mar 06, 2007 1:28 pm
by lllab
further tests show that this happens also without alpha-weightmap-transparency with just one ior gold layer?!

it is a single surface without thinkness- is that not supported by ior? i thought it wouldnt matter because it has no tranparency or index of refraction is involved. and giving it a thickness looks wrong when using perforation?

cheers
stefan

Posted: Tue Mar 06, 2007 1:41 pm
by tom
Images from output and material settings please..

Posted: Tue Mar 06, 2007 3:01 pm
by lllab
can i send i directly cause the images are under nda?

cheers
stefan

edit: material settings are very simpel:
1basic layer with weight mask:
IOR gold
20% roughness
1 basic layer with inverted weightmask:
color0= white
transparency white 255,255,255
nd=1
att distance 999m
lambert
roughness =0

the rendering has light intensive blue areas where the metall fassade has the physical sky behind, this happens also with just the first basic ior layer in the material

Posted: Tue Mar 06, 2007 6:27 pm
by tom
Make sure you are using a correct weight map. The pixels to be *completely* clipped in your weightmap must be pure white (255,255,255).

Here is a valid test with Weight [ior+ghost] under physical sky with sunlight:
Image

Posted: Tue Mar 06, 2007 7:06 pm
by lllab
thanks tom for testing,

my weightmapp is completely white 255,255,255 at the white parts.
in your example there isnt the sky behind the object, my object has no thickness, as i need to simulate a perforated metallsheet.maybe this is not "allowed" with ior.

could you test that in a short test-the sky behind the object(not the floor), and only a surface?

i hope i am doing something wrong, just cant figure out what...

thanks for helping
cheers
stefan

p.s. i recreated the problem with a simpel file i post it soon here...

here is the testfile:
http://maxwellrender.at/files/

Posted: Wed Mar 07, 2007 11:29 am
by lllab
hi tom,
does this file "behave" wrong for you too?
could you test it?

cheers
Stefan

Posted: Wed Mar 07, 2007 12:43 pm
by tom
Hi Stefan,

Well, yes this is not a clipping/weight mapping problem. It's a known issue when rendering some ior files and already fixed for 1.2. ;) Try rendering a gold without weighting/clipping it. That problem will still remain with 1.1. Also try only changing gold ior to another ior, it may also render fine. As I've said, this was just about rendering particular ior files.

Here're the results with pre-1.2:
Image

Your scene with pre-1.2:
Image

So, let's move this under bugs section and tag as fixed ;)

Thanks,
tom

Posted: Wed Mar 07, 2007 12:45 pm
by lllab
"It's a known issue when rendering some ior files and already fixed for 1.2."

thanks tom, great its already fixed:-)
cheers
stefan

Posted: Wed Mar 07, 2007 1:44 pm
by sandykoufax
pre-1.2 ?

:shock: :shock: :shock: :shock:

Posted: Wed Mar 07, 2007 9:54 pm
by lllab
preversion of 1.2;-)

hope fully soon converts to official version of 1.2
cheers
stefan