Equirectangular coordinates for environment

I’ve been experimenting with generating equirectangular images for use as environment textures. It almost works.

  1. I create a 2048x1024 test image with graphics software - latitude and longitude grid.
  2. I assign the image to an Environment Texture node, Equirectangular.
  3. I place the camera at the origin and rotate it to various positions. Everything looks exactly as expected.
  4. I place a mirror ball at the origin and aim camera at it, from various positions. Everything is a little “off”.
  • Front view shows both poles
  • Top/bottom view shows entire equator
    Camera and vector adjustments don’t seem to fix this. Am I missing something basic?
    Images attached - .blend not interesting. (actually I am using .png)
    Test grid, front view, top view.

Using 2.73a and obviously Cycles, sorry.

Are you sure that’s wrong? Mirrored balls can show you more than 180º, that’s why mirror ball HDRIs are (almost) 360º, not 180º. If you hold up a chrome ball, you can see things “behind” the ball in the reflection.

Thanks for the response. I can’t say it is wrong, but it certainly was unexpected. I guess I can go back to do some math and try to prove it to myself.

Indeed, instinct is quite misleading. Trust the geometry…