Construction Aid Circle > Object - Object - Object (Construct Menu)

This command draws a Construction Aid circle which is tangent to three objects (line, circle, Construction Aid line, or Construction Aid circle).

If a Construction Aid circle is to be drawn while working in isometric or dimetric views, this must be done with the command Construction Aid Ellipse > Vector - Vector because the result on the page is not circular but elliptical.

Any line or circle in an existing object can be identified as the first reference object. This can also be a side of a rectangle or a leg of a circle segment.

The position at which the line is identified (the "ID point") does not affect the rest of the command. Because there are four possible results, choosing them based on the position of the ID points would be too complicated.

Any line or circle in an existing object can be identified as the second reference object. This can also be a side of a rectangle or a leg of a circle segment.

Any line or circle in an existing object can be identified as the third reference object. This can also be a side of a rectangle or a leg of a circle segment.

After identifying all three reference lines, all the possible Construction Aid circles are calculated (the graphic shows one possible set of results)

The desired circle can then be chosen with the help of a small dialog. Only one circle can be chosen at a time.

If all three reference lines are parallel to one another, it is not possible to calculate the Construction Aid circles. In this case, a corresponding error message appears. It does however work if only two of the reference lines are parallel to one another.