gadoid nous apporta ses lumieres en ce 2007/09/06 22:23:
> "Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
>> "gadoid" <hansen at tkgate.org> wrote:
>> ....
>>
>> I may have narrowed the problem down for you.  It appears to be affected
>> ultimately by the size of the normals of the plane behind the spheres.
>>
>> Try removing the plane normal or making it smaller and see what happens.  It
>> doesn't matter what normal type you have on the spheres, so it's not related
>> to the crackle pattern.  Whatever is causing it, the normals on the plane
>> appear to be getting reversed by the spheres.  For example try rendering
>> with "bozo 4" normal on the plane and then "bozo -4" and compare.
>>
>> Hope this can help someone track down the reason or bug causing it.
>>
>> -tgq
> 
> I did notice the problem only happens when the surface beyond has a normal.
> You are right that it may be reversing the normal, I at first thought it was
> just shifting it.  I'm beginning to think that this must be a POV-Ray bug,
> but if it is, I need to find a work-around for my scene.  I can't get rid
> of the "normal" on the surface behind the object, because that is water and
> I am using the normal to generate the waves.  I have hundreds of the
> "electron" objects in the scene.  The only thing I can think of is to
> #declare a different object for every orientation I need since the
> unrotated objects seem to render fine.
> 
> 
> 
> 
> 
> 
> 
Don't rotate the texture! Instead, create the objects at the origin, rotate the 
objects, thanslate them to the final position. As you are using spheres, 
rotating the object or the texture will wave the same final aspect, minus the 
normal alteration.

In my tests, the effect depends on the axis of rotation relative to the 
camera-object vector. An object with a z rotation just in front of the default 
camera show no effect, while the same object shifted up/down or lateraly will 
exibit the effect.

-- 
Alain
-------------------------------------------------
When you don’t know what to do, walk fast and look worried.

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