TechDraw Dimension Link

Description
The Dimension Link tool creates a link between 3D geometry and 1 or more Dimensions on a Page. This link allows the Dimension to use actual 3D values instead of 2D projected values.

How to use

 * 1) Create your Dimension on the drawing page as usual.
 * 2) Select geometry (ex an Edge) in the 3D model view that corresponds to one of your Dimensions.
 * 3) Press the  button
 * 4) A dialog will open. Select 1 or more Dimensions to be linked to the selected 3D geometry.
 * 5) Press "OK"

Properties

 * 1) The MeasureType property of a linked Dimension will be changed from "Projected" to "True".

Scripting
TechDraw API and FreeCAD Scripting Basics.

The Dimension Link tool can be used in macros and from the Python console by using the following functions:

Limitations

 * 1) Dimension links are very sensitive to the "Topological Naming" problem.  It is recommended that linking Dimensions be one of the last steps in your process.
 * 2) The Link tool will not stop you from making illogical links.
 * 3) There is currently no way to break a link.  You can change the MeasureType back to Projected and the Dimension will use the Projected value instead of the True value.