1

I have a equirectangular 360 panorama photo. I tried to use it as a texture for a default Unity Sphere. The image had artifacts/visible seams, especially near the "poles" of the sphere (north pole and south pole).

Here is an example of the artifacts.

sphere mapping artifact

I also have the same image rendered by some third party apps, where it looks ok: enter image description here

How can I fix this?

K.L.
  • 795
  • 2
  • 11
  • 25
  • Can you show us a picture of the effect? There are so many kinds of artefacts possible. hard to guess which type is giving you trouble :). – Roy T. May 04 '15 at 16:32
  • @RoyT. added :) – K.L. May 04 '15 at 17:09
  • Out of curiosity, have you tried creating a sphere in something like blender and importing it with UVs into unity? I wonder if the UV mapps are borked – Joe May 04 '15 at 18:06
  • 1
    @Joe that was my first thought and I experimented with exporting spheres from blender, increasing mesh density etc. The artifacts were different or at different places, but overall still there. The third party app I use for reference does not have those issues. Still, I don't know much about 3d modelling, topologies and UV mapping, so I thought I do something wrong on a fundamental level. I've read that most 360 photos use equirectangular projection http://renderstuff.com/publication-files/0133/equirectangular-projection-of-an-interior-scene.jpg but I don't know how to use that knowledge. – K.L. May 04 '15 at 18:17
  • 4
    Standard UV mapping is what's called "piecewise-linear" - each triangle tries to use a scaled/skewed/rotated triangle of the original texture. The trouble is that close to the poles, equirectangular projection is extremely non-linear, and will show artifacts unless your triangles are very very small. You'll need to either write a shader to look up from the texture using spherical coordinates, or switch to a different texture layout like a cube map. – DMGregory May 04 '15 at 18:21
  • 2
    @DMGregory you should definitely convert that into an answer. – Roy T. May 05 '15 at 08:30
  • @DMGregory Thanks a lot for your great explanations! If I have only a rectangular map available from NASA, I guess writing a shader to look up the values is the only way to go? Better yet, could you kindly take a look at my question here: https://gis.stackexchange.com/questions/245315/pole-distortions-while-mapping-an-equirectangular-texture-map-to-a-3d-sphere? Greatly appreciated! – Sibbs Gambling Jun 25 '17 at 22:06

0 Answers0