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washi
08-26-2010, 03:04 PM
Hi guys!

After many hours trying to solve this issue, it seems i wil not find it out by myself :(
I've got a strange shadow line appearing on my wall. It's a mia_material and my light is a spotlight with a physicalSun plugged into the mental ray light shader tab. I'm aware it's supposed to be a directional light plugged with a physical sun but, even if it make the bug disappear, i don't get the same results with it so...

Also, i did not had any bug of the sort by the past. I've tried many things like:
- delete the physicalSun node and plug it into new lights.
- change the wall's textures.
- moving the wall itself.
- checking the windows textures (there is one for the dusts in the corners).

It seems the bug only show up on this wall because i've tried to place some objects in front of it and it's only visible on the wall.

Here is my pict before that strange shadow, notice the red square:
http://lesfisch.perso.sfr.fr/CgtalkForum/elephant/before.jpg

here with the bug:
http://lesfisch.perso.sfr.fr/CgtalkForum/elephant/after.JPG


Well this is my first attempt for asking help. I hope i'm clear enought.
Thanks.

Washi.

washi
09-05-2010, 12:25 AM
No one? please :)

CGNitro
09-06-2010, 08:30 AM
hi wash,, the place u r pointing out in the wall is not clear enuf both look same for me atleast,,

may it has something to do with the texture u hav given the wall try changing the wall texture or tiling in

it, else post a zoomed render of the region where u get this problem,

kanooshka
09-06-2010, 01:46 PM
I think this may be a texture seam. Are you using a tiling texture for the wall? What about normal mapping? If so, make sure the UV's are aligned exactly to all sides of the uv grid. Could you put up a version of your wall texture as well as a UV snapshot?

washi
09-06-2010, 04:06 PM
Hi guys, thanks for replies.

Thing is, my UVs matches the wall, i actually uses a tiling texture on my wall and i also tried to replace the texture by an other one like a lambert or a blinn.
For more precisons, the wall texture is a mia_material_x and everything takes place with the bump node where i plugged a layered texture combining the diamond shape with the cloth background.
What is weird to me it's that the strange shadow line who looks like a texture seam's ain't showing up when the physical sun of my spotLight is off !

Here the diamond texture:

http://lesfisch.perso.sfr.fr/CgtalkForum/elephant/wallPattern.jpg

a closer view to the wall:

http://lesfisch.perso.sfr.fr/CgtalkForum/elephant/wallBig.JPG

If you'd like or/and got some time, i can email you the scene :).
Thanks.

Washi.

snikt
09-07-2010, 11:57 AM
Just wanted to to ask, if the file filter is set to quadratic or mipmap. or off.The tiling might work better by changing the filter type.
Cheers.

washi
09-07-2010, 01:11 PM
Just wanted to to ask, if the file filter is set to quadratic or mipmap. or off.The tiling might work better by changing the filter type.
Cheers.

Hi snikt! I've just try to change with any possible filters including "off" and nothing has change.
Too bad ^^.
Thanks anyway

kanooshka
09-07-2010, 02:15 PM
After taking a look at the scene I narrowed the issue down to the mia_physical_sun node, more specifically the shadow softness parameter. It seems that this parameter uses some sort of filtering on the shadow and therefore was causing artifacts. To fix the issue set the shadow softness parameter to 0 and instead, on your spotlight enable mental ray area light and finally scale your spotlight to a small size like 0.07.

washi
09-07-2010, 04:17 PM
After taking a look at the scene I narrowed the issue down to the mia_physical_sun node, more specifically the shadow softness parameter. It seems that this parameter uses some sort of filtering on the shadow and therefore was causing artifacts. To fix the issue set the shadow softness parameter to 0 and instead, on your spotlight enable mental ray area light and finally scale your spotlight to a small size like 0.07.

Waow kanooshka, you just made my day =)!!
I can't believe i did not even think of check this.
Thanks a thousand times, i can finally render this scene.

if I can help you one day in anything, it will be with great pleasure.
Thanks again.
Washi.

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09-07-2010, 04:17 PM
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