|Sketch → Sketcher constraints → Constrain angle|
|Constraint Length, Constraint Perpendicular|
Angle constraint is a datum constraint intended to fix angles in sketch. It is capable of setting slopes of individual lines, angles between lines, angles of intersections of curves, and angle spans of circular arcs.
There are four different ways the constraint can be applied:
To apply angle constraint, one should the follow the steps:
As with any datum constraint, it is possible to change the angle value later by double-clicking the constraint in constraint list or 3d view. Entering a negative value will cause the angle direction to flip.
Accepted selection: line
The constraint sets the polar angle of line's direction. It is the angle between the line and X axis of the sketch.
Accepted selection: arc of circle
In this mode, the constraint fixes angular span of a circular arc.
Accepted selection: line + line
In this mode, the constraint sets the angle between two lines. It is not required that the lines intersect.
Accepted selection: any line/curve + any line/curve + any point
In this mode, angle between two curves is constrained at the point of their intersection. The intersection point can be on curves' extensions. The point should be specified explicitly, since curves typically intersect in more than one point.
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 angle between curves will be constrained at the point. These helper constraints are plain regular constraints. They can be added manually, or deleted. There are no helper constraints on the example picture above, because the point selected is already the intersection of curves.
Angle Constraint can be created from macros and from the python console by using the following:
# line slope angle Sketch.addConstraint(Sketcher.Constraint('Angle',iline,angle)) # angular span of arc Sketch.addConstraint(Sketcher.Constraint('Angle',iarc,angle)) # angle between lines Sketch.addConstraint(Sketcher.Constraint('Angle',iline1,pointpos1,iline2,pointpos2,angle)) # angle-via-point (no helper constraints are added automatically when from python) Sketch.addConstraint(Sketcher.Constraint('AngleViaPoint',icurve1,icurve2,geoidpoint,pointpos,angle))