On 03/03/2017 05:43 AM, William F Pokorny wrote:
> The three attached images were created using two new patterns called
> hard_object and soft_object. They can be found in the patch branch off
> master (3.7.2) at:
>
> https://github.com/wfpokorny/povray/tree/feature/soft_objectAndhard_objectPatterns
>

One of my goals with the hard_object pattern was to get to where we 
could pass an object with a defined inside to some macro and have it 
create a peeling paint (PP) (or other surface-skin) isosurface for that 
object without the need for extra outside steps.

While obviously not a complete/correct PP implementation, using a 
superellipsoid - as Thomas did in his original peeling paint texture 
postings - kinda functions. See the attached image.

The bad news is I don't think the performance is tolerable - except 
perhaps to those with 32 or more fast, real cores willing to endure some 
long renders...

Suspect part of the issue is in doing everything on the fly necessarily 
puts the crackle pattern into the overall function being evaluated where 
it was previously a separate 2D-in-evaluation outside step. Often the 
case with isosurfaces; Put a handful of slightly slow things together in 
a function, stick it in an isosurface and you get glacially slow. :-)

Anyway, off to do some performance profiling to see if I can nudge the 
technique into the practical realm.

Bill P.

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