on
the Modes panel of the Measurement
ribbon. This switches between the Z (height) coordinate of any object snapped to being forced to be zero or free to use the Z coordinate (if any) of an object snapped to.
Click the Zero Height
Mode toggle button on
the Modes panel of the Measurement
ribbon.
Users have little control over the drawings they are sent for measurement. More frequently these days, 3D is being used in CAD packages, but the drawing is generally saved in Plan view and therefore the 3D objects may not be immediately obvious.
This has the potential to cause errors when digitising in plan view as the path taken may in fact be following a 3 dimensional route, thereby given misleading results.
Zero Height OFF
In the following screenshot, the drawing has 3D objects in it and the continuous length measurement #1 has been digitised in plan view.
Switching to an isometric view, using 3D Orbit, reveals
the problem. The object snaps have grabbed the top of the wc wall
as it is a 3D object, resulting in an incorrect length measurement. This
is because the 'Zero Height' model is switched
off. This is perfectly
acceptable as long as the user is sure they want to measure this route.
Although this is quite obvious in isometric, it could quite easily have been missed in plan view.
Zero Height ON 
Measurement #2 below was taken with the Zero height tool
switched on to
ensure that the digitised route remained in 2D even though the measurement
was made in the 3D isometric view and the tops of the walls were deliberately
picked (note the differences in measurement values #1 and #2).
With Zero Height Mode ON the z axis value is always zero, irrespective of the position of the geometry being snapped to.
When Zero Height Mode is ON the a 0,0 icon appears by the cursor cross hair when picking points. There is no icon when Zero height Mod is off.
Unlike the other modes, the Zero Height Mode can be toggled ON and OFF whilst taking measurements.
Note: Neither setting will affect the Rise & Fall measurement command once it has been started.
The other Modes are:
· Notes
· Repeat