jbbarnes wrote:

>I can set the image size and then play around with rotate
>statements, but it's all guesswork because I don't understand the logic
>behind the mapping process. I've learned that if I simply rotate the sphere
>itself after the image is mapped, I get undesirable effects because only
>looking dead-on gives a flat image. From other directions the image is
>stretched and distorted. So I need to rotate the image as it is placed on
>the sphere. But the x, y, and z don't work as I expect them to.


I think Jaime's reply above is your basic problem. Start with the sphere at
<0,0,0>. Also move your texture to <0,0,0>.

That's what his translation here does;
   pigment {
      image_map { jpeg "nebula.jpg" interpolate 2 }
      translate <-.5,-.5,0>
   }

The image_map by default is 0 and goes to 1.  Jaime's translation centers it
to 0. Then you can rotate and it should work like you expect.

RG

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