Creating Boundaries

You can create the boundary curve of a surface or the boundary point of a curve by selecting a surface edge or a surface.

This task shows you how to:

Before you begin: Create a 3D shape containing a surface.
See Also
About the Color Management of Boundaries
In the Knowledge Base
Procedure to copy/paste a boundary from one document to another

Create a Boundary Curve by Selecting a Surface Edge

You can create boundary curves by selecting edges of surface.

  1. From the Transform section of the action bar, click Boundary .
  2. Select the Propagation type.
    OptionDescription
    Complete boundary The selected edge is propagated around the entire surface boundary.
    Point continuity The selected edge is propagated around the surface boundary until a point discontinuity is met.
    Tangent continuity The selected edge is propagated around the surface boundary until a tangent discontinuity is met.
    No propagation No propagation or continuity condition is imposed, only the selected edge is kept.
    Tip: You can select the propagation type before selecting an edge.
  3. In the Surface edge box, select a surface edge.
    The boundary curve is displayed according to the selected propagation type.
    No propagation
    Tangent continuity
    Point continuity
    Complete boundary
    Note: If you select a curve which has an open contour, the Propagation type becomes available: select the No Propagation type and select the curve again. The extremum points will define the boundary result.

  4. Optional: In Limit 1 and Limit 2 boxes, select two elements to relimit the boundary curve.

    Note: If you relimit a closed curve by means of only one element, a point on curve for instance, the closure vertex will be moved to the relimitation point, allowing this point to be used by other features.

  5. Click OK.

Create a Boundary Curve by Selecting a Surface

You can create the boundary curves by selecting a surface.

  1. Click Boundary .
  2. In the Surface edge box, select the surface.
    The Propagation type no longer is available, as the complete boundary is automatically generated:

Provided the generated boundary curve is continuous, you can still select a limiting point to limit the boundary.

Using the arrow, you can then invert the propagation of the limited boundary.