CGTalk - RAT Problem: Reversed Normal ?

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bahman

12-19-2004, 05:40 PM

Hi Everyone

I have a problem with bump in "Prman 11.3".

I'm using rat 5.5. In "Slim", I made a Displacement and then I attached it to Ensemble (with simple blinn shader).

When I rendered the image, Normals on my surface in some areas became reverse (or I think that normals became reverse).

The option "Do Displacement" was disabled (With displacement this problem doesn't occur).

It's a slim template problem or Did I forget something?

Did anyone experience this problem, any solution would you recommend?

playmesumch00ns

12-20-2004, 10:24 AM

It's hard to tell exactly what's going on without a picture. To check if the normals really are reversed, try rendering one image with a light behind, and one image with a light in front.

If it is the normals, it's very unlikely that it's mtor that's doing it. In some cases prman can be quite sensitive to normal direction, so check your model with backface culling turned on to see if everything's ok.

If that's not it post some pictures and I'll try and figure what's going on

bahman

12-20-2004, 10:52 PM

I Did a mistake. Its not reversed. but I think Its mirrored. becaues I maked a scene with a light in front & back of a sphere , then I rendered Image & I didnt have problem .

but when I maked a Light ,That was directing form left to right, I got unNatural effet as You can see in this image. (Marked areas with red color)

(Link Updated)

(http://www.imagehosting.us.com/showimage.php?id=8205&h=905373)

(http://www.imagehosting.us.com/showimage.php?id=8206&h=652651)
http://www.imagehosting.us.com/image.php?id=8206&h=652651

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