To Merge Contiguous Curves or One-Sided Edges
1. Select two or more contiguous curves or one-sided edges belonging to the same surface in the graphics window.
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IDD merges one-sided edges of the same surface only.
You must select curves of the same type. That is, all the one-sided edges that you select must either be UV- or 3D-curves. You cannot merge UV-curves with 3D-curves or 3D-curves with UV-curves.
2. Click Edit > Merge Curves or right-click and access Merge Curves on the shortcut menu.
The two or more contiguous curves or one-sided edges are merged into a single curve or one-sided edge. The resulting curve or one-sided edge can change shape to maintain smoothness.
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When merging one-sided edges, if the resulting geometry overlaps, the merge process is aborted.