FACEUNFOLD

FACEUNFOLD flattens a curved face of a solid or surface into a 2D outline, for example a cylinder, cone or bent plate. Faces curved in one direction unfold exactly. Faces curved in two directions get a best-fit approximation, and the command tells you so.

Starting

Type FACEUNFOLD on the command line. There is no ribbon button for it.

How it works

1. The command asks Select face to unfold (solid/surface uses its largest face):. Pick one face of a 3D solid or surface. If you select a solid as a whole instead of a face, its largest face is used. A surface or region selected as a whole is unfolded as a whole.
2. The face is unfolded. The outline is rotated to its smallest bounding rectangle, with the longest side along X.
3. The command asks Specify placement point (lower-left corner):. The outline follows the cursor. Click to place it.
4. The outline is drawn as a closed polyline in the XY plane of your current UCS. If the face has openings, they come along as separate closed polylines.
5. The command line shows a report of the form Unfolded: width x height, area 3D ... / flat ..., max edge stretch ...% (N triangles). These are the size of the flat pattern, the area of the curved and of the flat face, and the largest stretch of an edge.