|Sketch → Sketcher constraints → Constrain perpendicular|
Perpendicular Constraint makes two lines to be perpendicular to each other, or two curves to be perpendicular at their intersection. Lines are treated infinite, and arcs are treated as full circles/ellipses. The constraint is also capable of connecting two curves, forcing them perpendicular at the joint, similarly to Tangent Constraint.
There are four different ways the constraint can be applied:
To apply perpendicular constraint, one should the follow the steps:
Two curves will be made perpendicular at point of their intersection (either real, or of curves' extensions), and the point of intersection will be implicit. This mode is applied if two curves were selected.
If direct perpendicularity between selected curves is not supported (e.g. between a line and an ellipse), a helper point will be added to sketch automatically, and perpendicular-via-point will be applied.
Unlike for tangency, it is perfectly fine to reconstruct the point of perpendicularity by creating a point and constraining it to lie on both curves (thus constraining the point to the intersection).
In this mode, the endpoints are made coincident, and the joint is made to be right angle. This mode is applied when two endpoints of two curves were selected.
In this mode, an endpoint of one curve is constrained to lie on the other curve, and the curves are forced perpendicular at the point. This mode is applied when a curve and an endpoint of another curve were selected.
In this mode, two curves are made perpendicular, and the point of perpendicularity is tracked. This mode is applied when two curves and a point were selected.
"Any point" can be a lone point, or a point of something, e.g. a center of a circle, an endpoint of an arc, or the origin.
For the constraint to work correctly, the point must be on both curves. So, as the constraint is invoked, the point will be automatically constrained onto both curves (helper constraints will be added, if necessary), and the curves will be forced perpendicular at the point. These helper constraints are plain regular constraints. They can be added manually, or deleted.
Compared to direct perpendicular, this constraint is slower, because there are mode degrees of freedom involved, but it supports ellipses.
The placement of the point before the constraint is applied is a hint for the solver for where the perpendicularity should be.
Perpendicular Constraint can be created from macros and from the python console by using the following:
# direct perpendicularity Sketch.addConstraint(Sketcher.Constraint('Perpendicular',icurve1,icurve2)) # point-to-point perpendicularity Sketch.addConstraint(Sketcher.Constraint('Perpendicular',icurve1,pointpos1,icurve2,pointpos2)) # point-to-curve perpendicularity Sketch.addConstraint(Sketcher.Constraint('Perpendicular',icurve1,pointpos1,icurve2)) # perpendicular-via-point (plain constraint, helpers are not added automatically) Sketch.addConstraint(Sketcher.Constraint('PerpendicularViaPoint',icurve1,icurve2,geoidpoint,pointpos))