Constraint Tangent

Description
The Constraint tangent tool constrains a selected line (or an extension of it beyond its endpoints) to be tangential to a selected line, circle or arc in the sketch. Where the selected entities are two line segments, they are constrained to lie on the same line, i.e. be collinear.

Operation
Curve and a line.



Select the line and a circle in the sketch by clicking on them (highlighted in dark green).



Apply the Constraint tangent by either clicking on the Constrain tangent icon in the Sketcher Constraints toolbar or selecting the Constrain Tangent menu item from the Sketcher constraints sub-menu of the Sketcher menu (or the Part Design menu if the Part Design workbench is selected rather than the Sketcher workbench.



The line (or an extension of it beyond its endpoints) will be constrained to be tangent to the circle or arc by altering any or all of the line slope, the circle or arc radius or center point of the circle or arc depending upon what other constraints are operational in the sketch.

The tangent constraint can also operate on two selected points or a selected point and an edge(line)as illustrated in the following sequence.



First select two points (vertices) at the ends of two arbitrary lines.



Apply the Tangent Constraint as before.



The two lines ending in the two selected points are constrained to be collinear. ( A straight line is a curve of zero curvature or infinite radius hence collinearity follows from the definition of a tangent to a curve).

Similarly by selecting a point (at the end of a line segment and a line,



and applying the Tangent Constraint as before



the line ending in the point and the other selected line are forced to be collinear.