POV-Ray : Newsgroups : povray.newusers : image_map to tilted and rotated triangle centered and scaled : Re: image_map to tilted and rotated triangle centered and scaled Server Time
3 Jul 2022 21:01:38 EDT (-0400)
  Re: image_map to tilted and rotated triangle centered and scaled  
From: Tor Olav Kristensen
Date: 2 Apr 2022 20:50:00
Message: <web.6248ee41ccfe29006d7cc5a589db30a9@news.povray.org>
"Molly-J" <nomail@nomail> wrote:
> I am going mad trying to project image maps onto polygons that are not in the
> x-y plane or plumb to the y axis. I have 20 equilateral triangles forming a
> typical D20 shape (regular icosahedron). I have the XYZ coordinates for the
> points so all I have to do is create each triangle using sets of the 32
> vertices. BUT . . . .
>
> I cannot work out how to project the 20 image_map pigments properly. Image_map
> pigments only seem to work on polygons normal to the Z axis and left corner at
> 0,0 XY
>
> The suggestion that I create each triangle at 0,0 and then translate/rotate them
> to the icosahedron would be just fine if i had those numbers. (I do not)
>
> There must exist another way, as the current limitation is ludicrously
> un-useful. Everybody aplying pictures to polyhedra would have exactly the same
> problem.
> What am I missing?
>
> Is it possible to translate the triangle by translating its individual points?
> That I might be able to do, but I can't work out how.
>
>
> The ultimate goal is a Dymaxion type world map on an Icosahedron.

Hi again Molly

I've now made a couple of GitHub repositories that may be useful for you.

Here you can find the vertices and the triangles that you need:
https://github.com/t-o-k/POV-Ray-icosahedron

Here you can see how you can UV-map parts of an image onto a mesh2:
https://github.com/t-o-k/POV-Ray-UV-mapping-of-mesh2

And here you can download images suitable for being mapped onto an icosahedron:
https://solarviews.com/cap/ico/icoearth.htm

--
Tor Olav
http://subcube.com
https://github.com/t-o-k


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