[Sidefx-houdini-list] Shading artifact when really close to surface

guillaume laforge guillaume at alamaison.fr
Wed Oct 21 06:12:52 EDT 2009


Hi,

I've got some shading artifacts when using micropolygon rendering with a
camera really close to a geometry.
The camera is tangent to the surface of a sphere. The sphere radius is 6371
unit with a white lambert shader.
When the camera distance to the surface is around four units, some patterns
appeared in the shading of the sphere.
At a distance of one unit, it is really "bumpy" !
If I'm rendering polygons as subdivision surfaces it is worst (and when need
to render this way).
If I increase the shading quality, it is worst too.
If I switch to Raytracing renderer, the problem disappear. Unfortunately we
need to use Micorpolygon Rendering for this project.

I tried to scale down all the scene but it doesn't work. I guess the problem
came form the ratio between sphere radius and camera/surface distance being
too big...

Is there any magic settings to remove this kind of artifact, or is it a
precision limitation of the micropolygon system.

Thanks for any advice,

Cheers.

-- 
Guillaume Laforge
3D at la maison.
http://www.alamaison.fr
my blog : frenchdog.wordpress.com/



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