Surface boundary

Surfaces are specified in a rectangular array of rows and columns. This enables you to extract individual curves in the surface, especially those on the boundaries.

Boundary curves are useful as a step in building and modifying surfaces. For example, you probably want to extract boundary curves to build a cap surface.

Note: You can use the Surface Boundary dialog to find the seams of a closed surface, such as a cylinder, and then cancel the dialog without creating a curve.

Surface boundary extracts the curve from a surface's boundary:

1. Select Construct tab > Curves panel > From Surfaces > Boundary to display the Surface Boundary dialog.
2. Optionally enter a curve name in the Name field, or leave the default name.
3. Select the surface you want to use from the Surface menu, or use the Pick Surface button to select it in the Graphics window.
4. Use the Pick Curve button to pick a boundary in the graphics window, or select from:
   • First Row
   • Last Row
   • First Column
   • Last Column

   The selected boundary is highlighted in red in the graphics window.

5. Click OK.