The symmetrical constraint constrains two selected points to be symmetrical around a given line, i.e., both selected points are constrained to lie on a normal to the line through both points and are constrained to be equidistant from the line. Alternatively it can constrain two points to be symmetric with respect to a third one.
Select two points (vertexes) in the sketch and a line in the sketch. The selected points and the line will be dark green.
Click on Constrain symmetric or select the Constrain Symmetrical menu item from the Sketcher Constraints sub menu of the Sketcher (or Part Design) menu item.
This will apply the constraint to the selected items.
Note: Before Version 0.19 (see fix ), if you want to define a symmetry constraint with respect to a point, the order of the selection is important, depending on if you select the tool at the beginning or at the end.
- If you click the tool first: select the first point, then the symmetry reference point, and finally the second point.
- If you click the tool last: select the first point, then the second point, and finally the symmetry reference point.
See the tracker issue #4144, and forum thread.
Two points and a symmetry line:
Sketch.addConstraint(Sketcher.Constraint('Symmetric', Line1, PointOfLine1, Line2, PointOfLine2, SymmetryLine))
Two points and a symmetry point:
Sketch.addConstraint(Sketcher.Constraint('Symmetric', Line1, PointOfLine1, Line2, PointOfLine2, LineS, PointOfLineS))
A line and a symmetry point (In the GUI one can select a line and a point, but it uses internally the same form as above, with the two extremities of the same line):
Sketch.addConstraint(Sketcher.Constraint('Symmetric', Line, 1, Line, 2, LineS, PointOfLineS))
The Sketcher scripting page explains the values which can be used for
PointOfLineS, and contains further examples on how to create constraints from Python scripts.
- Sketcher geometries: Point, Line by 2 point, Create an arc, Arc, Arc by 3 Point, Create a circle, Circle, Circle by 3 Point, Create a conic, Ellipse by center, Ellipse by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola, Create a B-spline, Create B-spline, Create periodic B-pline, Polyline (multiple-point line), Rectangle, Create regular polygon, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Create Regular Polygon, Slot, Fillet, Trimming, Extend, External Geometry, CarbonCopy, Construction Mode
- Sketcher constraints
- Geometric constraints Coincident, Point On Object, Vertical, Horizontal, Parallel, Perpendicular, Tangent, Equal Length, Symmetric, Constrain Block
- Dimensional constraints Lock, Horizontal Distance, Vertical Distance, Distance, Radius, Internal Angle, Snell's Law, Internal Alignment, Toggle reference/driving constraint,
- Sketcher tools Select solver DOFs, Close Shape, Connect Edges, Select Constraints, Select Origin, Select Vertical Axis, Select Horizontal Axis, Select Redundant Constraints, Select Conflicting Constraints, Select Elements Associated with constraints, Show/Hide internal geometry, Symmetry, Clone, Copy, Move, Rectangular Array, Delete All Geometry, Delete All Constraints
- Installation: Windows, Linux, Mac; Getting started
- Basics: About FreeCAD, Workbenches, Preferences, Document structure, Interface Customization, Properties, Mouse Model; Tutorials
- Workbenches: Arch, Draft, FEM, Image, Inspection, Mesh, OpenSCAD, Part, PartDesign, Path, Plot, Points, Raytracing, Reverse Engineering, Robot, Ship, Sketcher, Spreadsheet, Start, Surface workbench, TechDraw, Test Framework, Web
- Scripting: Introduction to Python, FreeCAD scripting tutorial, FreeCAD Scripting Basics, How to install macros, Gui Command, Units Modules: Builtin modules, Workbench creation, Installing more workbenches Meshes: Mesh Scripting, Mesh Module Parts: The Part Module, Topological data scripting, PythonOCC, Mesh to Part Coin scenegraph: The Coin/Inventor scenegraph, Pivy Qt interface: PySide, Using the FreeCAD GUI, Dialog creation Parametric objects: Scripted objects Other: Code snippets, Line drawing function, Embedding FreeCAD, FreeCAD vector math library, Power users hub, Python, Macros, FreeCAD Scripting Basics, Topological data scripting