Le 19-04-06 à 15:09, Tamas Gunda a écrit :
> I created 3D cube images with Povray - spherical images assembled from 6 images,
> each of the images corresponding to one face of a cube. Without using radiosity
> there are no problems. However, if radiosity is turned on, the six images do not
> fit exactly, there are differences in brightness of the faces. The code is the
> exactly the same for all faces, only the camera is rotated by 90 degs. Seems
> that the result of rendering with radiosity turned on depends on the camera
> direction.
> 
> To better understand, have a look at www.gunda.hu/cube/povray
> 
> Another perfect example, without using radiosity, is at www.gunda.hu/cube
> 
> 
> 

Strange, radiosity have no effect of the geometry and should be 
independent of the camera's location and orientation.

What can happen is a difference on what areas radiosity is sampling. If 
that's the case, increasing the count value should help, also, using the 
two values variant often help :
count 175 25000

You may also want to reduce the value for pretrace_end. Default is 0.04. 
Try 0.01, 0.005 or 0.0025.

Looking at the dark end and you really need more samples. Quadrupling 
your count value may not be quite enough. You may also need to increase 
the recursion_limit value to 4 or maybe 5. Also, reducing minimum_reuse 
could also help. Default is 0.015. Try 0.01 down to 0.004.

Adding some roundness to the edges can do a lot in reducing the 
artefacts in the darker areas. A clipped cylinder will do the trick.

If you can post the source of your scene, it'll be easier to diagnose 
the issue and help you.



Alain

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