On 10/13/19 3:15 PM, Bald Eagle wrote:
> William F Pokorny <ano### [at] anonymousorg> wrote:
> 
> I'm not at all sure what deep C++ functions and libraries you're dealing with -
> that gets down to a deeper level than I have ever gone.
> 
> I think I understand what you're struggling with - it's akin to the coincident
> surface problem - so let me ask - would adding something like crand / jitter /
> some other random noise to the function make it better or worse?
> Say, something with a range from 0.99999 to 1.00001?   Or 1+/- E-7?
> 
> Not that it solves the underlying problem, but since it went undiscovered / was
> well enough hidden for _this_ long, maybe the thing to do is just build a
> deeper, plusher rug to sweep it under, with the humblest of apologies and a most
> heartfelt promise to come back and fix it "later"   ;)
> 

:-)

Often I bump the isosurface boundary a little, hide or avoid parts not 
right - ten plus years of it. Often, I walk away from ideas in 
frustration because POV-Ray doesn't work as intended.

I hit the issues here more than most because I play with isosurfaces. It 
should be the tiling patterns and others provide a rapid path to complex 
shapes with low gradients. Shapes where we can use all the usual pattern 
modifiers and extensions. The larger mechanisms are there, but they 
don't completely work. It's frustrating.

Your recent posts in part motivated me push again on tiling patterns 
with isosurfaces. I can these days often determine the core problems in 
the source code. I uttered the words, "let's figure this out." (He talks 
to himself too...)

Started expecting a problem or two. Found a half a dozen bugs / 
shortcomings. I've in hand code addressing most. A worry the changes 
ripple into parts of POV-Ray in ways I don't presently see. The 
abs/min/max concerns are secondary and general.

Many of my wild ideas require warps - bending assemblies rather than 
blobbing assemblies. I often cannot avoid the mod/fmod harmonics without 
introducing visible seams due the avoidance. I'm stuck between a rock 
and a hard place, off the beaten path - in the weeds.

Speaking of rugs - and now completely drifting - I believe a secrete 
attraction of physically-based / stochastic rendering methods is the 
approach covers for train loads of numerical sin. Rugs and trains - 
where's Ton... ;-)

> 
> It's always the edge cases that take 90% of the time...   :|

Yep!

> 
> Perhaps there's something along the lines of this that might spark some ideas?
>
http://news.povray.org/povray.general/thread/%3Cweb.5c85aaecd4241a93765e06870%40news.povray.org%3E/
> 
Yes, I remember. A similar discussion. :-)

Bill P.

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