Hi Michael et al,

Thanks for the elucidations, much appreciated.

The reason for my question was that I figured that having a seam's orientation aligned to the seams of other parts of a 3D model will cause better topology continuity after boolean operations. For example, when I trim a cap of an extruded or lofted curve, I tend to trim it from the seam to the opposite side, and blend the two halves. But if the seam doesn't matter much, then I'll forget this. I did notice that having seams exactly aligned can cause fillets to fail after a boolean union.