On 4/26/24 21:02 (-4), Bald Eagle wrote:
> 
> Cylindrical means cylindrical.
> And you're deviating from that to toroidal.

My intended task was to bend a solid texture into an arc.  That it is
applied to a torus is incidental.  I can't even begin to imagine dealing
with warp { toroidal }.  (What you see in the animation is a solid
checker pattern.  If I were dealing with uv-mapping, of course I would
have used toroidal.)

> If I had to guess the best way to do that, it would be by geometric inversion.
> Your cylinder would be a torus of infinite radius, and then you'd translate it
> relative to the center of inversion until you got a torus with the desired major
> radius.

I suppose if I were doing those calculations myself, I'd at least know
what I was doing.  But without thinking too hard about it, it seems like
an overly convoluted and unnecessarily difficult way to get it done.
The main difficulty with warp { cylindrical } was getting all the parts
oriented and scaled properly, but the end code is remarkably simple, if
somewhat head-scratching.

FWIW, I did work from the center of curvature, then translate.  And of
course, the unbent object (which does not appear in this animation,
because it is between frames) is a special case using a straight
cylinder, because infinite radii and translations are not fun.

> Excellent job getting it all to work!
> I'm sure it must have been a hard slog to the finish line.

Thanks!

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