Sketcher ConstrainPointOnObject

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Sketcher ConstrainPointOnObject

Menu location
Sketch → Sketcher constraints → Constrain point onto object
Default shortcut
Introduced in version
See also
Sketcher ConstrainCoincidentUnified, Sketcher ConstrainCoincident


The Sketcher ConstrainPointOnObject tool fixes points on edges or axes. Lines are treated as infinite, and arcs are treated as full circles/ellipses.

introduced in version 0.22: This tool is replaced by the Sketcher ConstrainCoincidentUnified tool if the Unify Coincident and PointOnObject option is selected in the Sketcher Preferences.


See also: Drawing aids.

  1. Do one of the following (optional if the tool will run in continue mode):
    • Select a single point and a single edge (in any order).
    • Select several points and a single edge (idem).
    • Select a single point and several edges (idem).
  2. There are several ways to invoke the tool:
    • Press the Constrain point onto object button.
    • Select the Sketch → Sketcher constraints → Constrain point onto object option from the menu.
    • Use the keyboard shortcut: O.
  3. If the tool runs in continue mode:
    1. The cursor changes to a white cross with the tool icon.
    2. Optionally keep selecting elements. You can only select two elements at a time now.
    3. To finish, right-click or press Esc, or start a another constraints or geometries tool.


The constraint can be created from macros and from the Python console by using the following command:


  • Sketch is a sketch object.
  • LineMoving is the number that designates the line, which contains the point that has to be moved onto the LineFixed (the line which is fixed).
  • PointOfLineMoving is the number of the vertex of line LineMoving, that has to be moved onto the LineFixed.
  • LinedFixed is the number of the line to be affixed onto the point PointOfLineMoving.

The Sketcher scripting page explains how to identify the numbers that designate lines and points.