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Curve on Surface

In one sentence: Creates a parametric curve constrained to lie on a face — defined in UV space so it updates when the surface changes.

Third-party addon — installation required

The Curves workbench is not included in FreeCAD. Install it via Tools → Addon Manager → search "Curves" → Install and restart FreeCAD.

Overview

Workbench: Curves
Menu: Curves → Curve on Surface
Command: cos

The curve is defined in the face's UV parameter space and projects onto the 3-D surface. If the surface changes, the curve updates automatically.

Common uses

  • Defining a trim boundary on a face
  • Creating a guide rail for a surface-following sweep
  • Tracing a seam or split line on a complex surface

See also