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December 27, 2004
Lollipop Mapping
When you UV map a sphere, you normally expect distortion at the North and South poles. If you preprocess your texture map in the right way, you can hide the North pole completely, at the expense of an "extra bad" South pole.
Think of it as wrapping paper over a lollipop.
An un-prepared image wraps around a sphere in Maya as expected.
With the usual North and South poles.
Use Photoshop to "pre-distort" the texture map. Choose filters > distort > polar coordinates. Be sure to choose the "polar to rectangular" option.
Now you have no North Pole!
...at the expense of an "extra bad" South Pole -- which you can hide either through careful choice of camera angles, or through the use of a second, upside-down texture map, carefully merged (at the equator) with the first map, so that the end result is a sphere with no visual poles at all.
Posted by digital artform at December 27, 2004 12:43 AM
Comments
I've created a tutorial some time ago that goes through the process of doing both poles - Sherical Mapping Tutorial. In my case I flip the map to do both poles and then clean up the seam if needed.
Posted by: Chris at December 27, 2004 05:44 PM
That's a good tutorial.
...It also serves to remind one that a spherical texture map also has many uses when the sphere is large and the viewer is inside it.
Posted by: Joseph Francis at December 27, 2004 07:04 PM