Wilbur - Compensating for equirectangular distortion

[Snorlock the Great]

Hello, I've encountered a bit of a hang up when it comes to erosion on my world map. I used Torben's planet generator to get my land masses and water. My output is an equirectangular texture map that is being applied to a sphere. It also gives me a basic height map which I have further enhanced with some manually-added mountain ranges. I take this height map into Wilbur to get some tasty erosion and rivers.

My problem is that Wilbur is applying erosion uniformly across the entire image which, of course, doesn't take into account the distortion that is present at the north and south poles. Is there a setting I can tweak that will make the Filter>Erosion, Filter>Fill, Filter>Morphological, (and I guess Filter>Noise) tools take projection distortion into account when applying their functions?

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[waldronate]

No, you can't make Wilbur take the projection into account. The erosion algorithms all assume that the area being eroded is planar (that is, that each sample is the same size and that the connectivity to its 8 neighbors is length 1 unit across the flats or sqrt(2) units across the diagonals).

The best that you can achieve with Wilbur is to make multiple height fields with each continent in its own projection centered on the landmass (an equal-area projection is a good start, but which projection will depend heavily on the size of your continents). There are some compromise projections that might work well enough if you stay away from the edges, but they can be hard to get (for example, a 45-degree rotated approximate sinusoidal will put poles at opposite corners of a square and the equator across the diagonal; this projection is hard to get if you have world-spanning continents, though).

[Snorlock the Great]

Ah, darn. That's pretty much what I expected I would have to do. Can FT3 handle it or does it have the same limitations?

Regardless, thanks for the great tool.