The Measure 
tool measures exact dimensions in part, assembly, and drawing documents.
Callouts display results, including the type of measurement, the value, and units.
On the
Measure 
tab, you can:
- Set selection filters. If you do not select a filter, all entities are available for measurement.
- Change the units.
- View measurement results.
You can select entities in any order. For example, to make an edge to face measurement, choose the edge or face first, then the second entity. For point selection, you can select vertices, endpoints, midpoints, and the endpoints of tessellated arcs and circles.
When you click any markup tool or Move Component 
, the Measure tool is turned off and all measurements disappear from the graphics area. You must click Measure again to activate it.
You can select planar faces only.
For isometric type drawing views, the projected length is displayed instead of the true length.
Measurements are not saved with the file. To create markup dimensions to save, see Dimensions.