On 1/25/22 16:15, Bald Eagle wrote:
> William F Pokorny <ano### [at] anonymousorg> wrote:
> 
>> The reflections which are there are no longer fuzzy though, which has me
>> puzzling. A significant number are pointing away / against the raw
>> surface normal sphere rather than mostly being aligned. Guessing we are
>> hitting some limit where maybe the perturbed normal gets ignored or
>> something except maybe for being inverted. I don't know! I'd have to
>> spend more time in the code to figure it out. The question is rattling
>> around up there in my empty space - maybe the reasons will fully come to me.
> 
> If you have a "+" normal, and a "-" normal of the same magnitude adjacent to one
> another, does the intermediate region get interpolated, and therefore the two
> normals cancel?
> 
> Perhaps if you apply AOI or SLOPE pigment patterns, you can pick up "flat"
> regions on the surface?   Maybe that's somewhere that your RAW thing will help?
> 
> Just guessing.
> 

Yeah, that's a thought. I didn't really think about the normal 
components potentially canceling and going to zero. It could happen, but 
I'd say not all that often - but maybe there is some clamping or cut 
offs somewhere in the code that get us to zeroing.

Using aoi a good thought too! The povr aoi pattern doesn't cut off like 
the official POV-Ray one does where the normals point away. I made this 
change so folks can to a degree see any perturbed normal inversions - 
they can run something to see at what bump_size they have a problem.

Any recent POV-Ray release support blend maps with arbitrary negative to 
positive ranges internally. Unfortunately, without changes like those in 
povr, one can't make use of the capability. Something to try.

Bill P.

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