i have a .png image file which is a stereographic projection image of the brightness of a sky visualized in falsecolor (the image is what you may see when you lying on the ground with head pointing towards due north and looking upward at the zenith).
Stereographic Projection:
http://en.wikipedia.org/wiki/Stereographic_projection [en.wikipedia.org]
May I ask how to map this image to a hemisphere surface as a material in Houdini?
Thanks!
- Ji
[solved] map stereographic image to a hemisphere
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- oat
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- eetu
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Your post does not strictly have enough information (parameters) about the projection.
Guessing that it uses the south pole as the projection point, here's a “brute-force” approach. Create normals that point to the south pole, raycast your points to a plane, apply a planar projection, copy uvs back to hemisphere.
Maybe one can do it in a smarter way by playing with the UVProject SOP, but I can't do it before my morning coffee
Guessing that it uses the south pole as the projection point, here's a “brute-force” approach. Create normals that point to the south pole, raycast your points to a plane, apply a planar projection, copy uvs back to hemisphere.
Maybe one can do it in a smarter way by playing with the UVProject SOP, but I can't do it before my morning coffee
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- eetu
- Member
- 607 posts
- Joined: May 2007
- Offline
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- oat
- Member
- 479 posts
- Joined: Dec. 2009
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