To Insert a Z-radius Dimension
1. Click
Annotate >
Annotations >
Z-Radius Dimension.
2. Select a model true arc or draft true arc. A ghost image of the Z-radius dimension appears.
3. Select a point for the imaginary center of the selected true arc. You can select a free point in the drawing to place the imaginary center or place the imaginary center on an entity. The Z-radius dimension is created between the selected true arc and this imaginary center.
Hold down the CTRL key and select an entity to snap the imaginary center along the selected entity.
4. Middle-click to exit the dimension creation mode.