From:  Michael Gibson
4553.6 In reply to 4553.4 
Hi Brian, also one thing to note about the "reverse flow" is that just like when you flow from a base plane on to a sphere target where there is compression happening at the pole areas of the sphere when you go in the reverse direction the same kind of thing will happen where there is a kind of expansion deformation happening in the unflowed result.

It's generally more like texture mapping and not the same as a "developable surface" - the 2D result won't work for example to make a pattern to cut to do a physical construction of the 3D object because of the expansion and compression that is happening.

But it still could be useful as a modeling tool - you could do something like unflow it to get a good idea of where in the plane you want to draw some things to then flow back on to the sphere.

- Michael