From FreeCAD Documentation
- Select a circle or circular arc. The geometry may be selected in the 3D view or in the drawing. Note some arcs which appear to be circular are actually ellipses or B-splines. You cannot make a radius dimension in these cases.
- If you have selected geometry in the 3D view: add the correct TechDraw View to the selection by selecting it in the Tree view.
- There are several ways to invoke the tool:
- Press the
Insert Radius Dimension button.
- Select the TechDraw → Dimensions →
Insert Radius Dimension option from the menu.
- A dimension is added to the View.
- The dimension may be dragged to the desired position.
- If needed, add tolerances as described on this page.