Op 24/01/2022 om 11:51 schreef William F Pokorny:
> On 1/23/22 07:49, Thomas de Groot wrote:
>> Very nice one! More images should "fall out"...
> 
> Thanks! :-)
> 
> It's on my todo list to aim more often for more complex images! For 
> whatever reason I always drift back into chasing things in the code.
> 
> Attached is another test image. The one where I first turned up the 
> POV-Ray issue with 'too large for our exr reader' channel values in the 
> exr HRDI sky_sphere file.
> 
> The three spheres are using different normal 'micro' pattern bump sizes. 
> Further the scene uses povr's intensity_max control in both the 
> reflection block and with the metallic in the overall finish block. The 
> latter keeps all the reflected colors in a 0-1 channel range where the 
> AA still works.
> 
> Most puzzling to me is the upper left sphere where I made the micro 
> bump_size large (1.5 I think). It happens once bump_size values get over 
> the usual 0.5 limit where normals can start to invert in one or more of 
> the x,y,z directions due the perturbation values being so large compared 
> to the raw normal values(a). Where perturbed normal inversions occur, 
> the result starts to look more like a milky glass. I don't completely 
> understand why...
> 
> Bill P.
> 
> (a) Only a few of povr's normal patterns prevent such inversions - and 
> micro doesn't.

That milky glass effect is quite nice imo, while the lower right sphere 
seems strongly overdone. Food for thoughts... especially the milky glass.

-- 
Thomas

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