Snaps work in 3D, but are most are projected onto the current workplane.
Therefore, to apply a dimension to a 3D object, you must set the workplane to the plane where you want the dimension to appear. In other words, you can display projected measurements in 3D.
For ACIS solid objects (TurboCAD Pro only), you can apply Radius and Diameter dimensions to arc-based objects. You must turn on Degenerative Faceting in the ACIS page (Options/ACIS). These dimensions are non-associative.