User:DeepSOIC

Description
Angle constraint 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.

How to use
There are four different ways the constraint can be applied:
 * 1) to individual lines
 * 2) between lines
 * 3) to intersections of curves
 * 4) to arcs of circles

To apply angle constraint, one should the follow the steps:
 * Select one, two or three entities in the sketch.
 * Invoke the constraint by clicking its icon on the toolbar, or selecting the menu item, or using keyboard shortcut. A datum edit dialog box pops up.
 * Modify the angle if necessary. Click OK.

To individual lines


The constraint sets the polar angle of line's direction. It is the angle between the line and X axis of the sketch. This mode is applied if one line was selected.

Accepted selection:
 * line

Between two lines


In this mode, the constraint sets the angle between two lines. It is not required that the lines intersect. This mode is applied when two lines were selected.

Accepted selection:
 * line +  line

Between two curves at intersection (angle-via-point) (v0.15)


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. This mode is applied when two curves and a point were selected.

Accepted selection:
 * any line/curve +  any line/curve  +  any 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.

To arcs of circle (v0.15)


In this mode, the constraint fixes angular span of a circular arc. This mode is applied when a circular arc was selected.

Accepted selection:
 * arc of circle

Scripting
Angle Constraint can be created from macros and from the python console by using the following:

where:
 * Sketch is a sketch object
 * icurve1, icurve2 are two integers identifying the curves to be made perpendicular. The integers are indexes in the sketch (the value, returned by Sketch.addGeometry).
 * pointpos1, pointpos2 should be 1 for start point and 2 for end point.
 * geoidpoint and pointpos in PerpendicularViaPoint are the indexes specifying the point of perpendicularity.