what you would do is not just take the edge normals, but create a spline from the connected edge flow (similar to Pior's arrows) and then create curvature information. ie literally slide the new vertices on the extended spline. this will not prevent you from overlaps and all that, which probably means you must try to…
I tend to overreact on stuff, so no worries Synch. yes the sampling is indeed tricky, but what you describe sounds well. Basically walk the edges of the connected polys and check if the edge has either point on opposite sides of the plane, then intersect. Walk along the polys of those edges that did intersect. or you…
About the curvature problem : while my diagram suggested that the new geometry should follow a 'guessed' curvature derived from the pre-existing geometry, in practice it is completely enough to just go 'flat' past the outer edge. In other words : lets imagine that we perform an Extrude, or a simple Shell, on the edge of…