|Sketch → Sketcher constraints → Constrain angle|
|Constraint Length, Constraint Perpendicular|
This tool constrains the angle between two selected lines in a sketch to be a specified value. By default, the internal angle, the smaller of the angles formed at the intersection of two lines (or their extensions) is constrained.
If a single line is selected, the angle is constrained relative to the horizontal axis of the selected sketcher plane
Select any two lines in the sketch by clicking on them in sequence. They will change colour to dark green when selected. The direction of the line form the first point created to the end point is significant in calculation of the angle between the lines.
Then click on the ConstraintAngle icon() in the Sketcher or Part Design toolbar or select the ConstrainAngle menu item from the Sketcher constraints sub menu of either the Sketcher (Sketcher workbench) or Part Design (Part Design workbench)menu item to add the constraint.
The constraint is initially set to the current internal angle between the lines and the Constraint is added to the Tasks tab in the Combo View panel.
Doubleclicking on the Constraint in the Tasks tab will bring up a pop-up dialog box in which this value may be edited to set it to a desired value. Alternatively, the datum text in the 3D view may be double clicked to bring up the pop-up dialog to set the value.
The value can be set to values greater than 180 (or even 360), in which case it becomes a constraint on the external angle and the angle is interpreted as modulo 360 degrees.
The absolute mode is invoked by only selecting one line before applying the constraint.
Applying the constraint, the angle is constrained relative to the horizontal axis of the selected sketch plane.
Selecting the second line which was drawn from the upper right to lower left.
And applying the constraint as before,
the line is now constrained to have a value relative to the direction of the horizontal axis in the clockwise direction (angle values are restricted to 180 degrees anticlockwise or clockwise).
As before by double clicking on the constraint in either the Tasks tab of the Combo view or on the constraint in the 3D view will allow editing of the value of the constrained angle.