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Join Curves

In one sentence: Joins multiple selected edges into a single continuous B-spline curve.

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 → Join Curves
Command: join

The result is a single B-spline that passes through the endpoints of all input edges in order. Useful for converting a chain of separate edges (e.g. from imported geometry) into one smooth parametric curve.

Step-by-step

  1. Select the edges to join (in the correct order).
  2. Choose Curves → Join Curves.
  3. A single B-spline replaces the chain of edges.

Alternatively, select an object containing multiple edges in the tree — the tool joins them automatically.

Common mistakes and pitfalls

Join Curves produces a coarse approximation

The joining algorithm approximates to a B-spline which may have fewer degrees of freedom than the input chain. Increase Max Degree or Max Segments if available, or use Approximate with a tighter tolerance.

See also