The Onshape Measure tool is available in Part Studios and assemblies, for measuring sketches, parts, assemblies, curves, and surfaces as well. The Measure tool appears in the bottom right corner of the interface in Part Studios and assemblies.

You can filter which measurements are shown by selecting a Measure type from the first dropdown. If pre-selections are made, the tool displays some information. For more information, click the icon to open the dialog:

Assembly Measure tool icon at lower right corner of the window 「測量」對話方塊 Measure dialog with an example of an Assembly

In addition, selecting any entity from the graphics area also automatically shows the pertinent measurements without having to explicitly open the Measure dialog.

You can also use the Measure tool on faces, edges, and vertices while in a Section view.