Today was my first chance to try automatic Z height pausing on a MakerBot Replicator 2.
The feature was added back in firmware version 7.3.0, and what it does is give users an extra menu option while a print is running, to choose at what height the printer should pause.
There are some limitations, though: the spot at which a pause takes place is unintuitive, and the height can be specified only in whole numbers. (ie 2 mm or 4 mm, but not 2.3 mm)
A client needed some company logos in two and three colours, so I first tried the procedure on some test objects.
I created a stacked cube and cylinder in 123D Design with these measurements:
Printing that at 0.2 mm layer height with a pause height of 2 mm produced a piece where the final layer of the cube was in the second colour:
After fiddling around with reducing the cube height by 0.00001 and 0.01 mm, I hit on the right way. I cropped 0.2 mm off of the cube, leaving it at 1.8 mm height:
Then, I set the pause height to 2 mm even (since we can only do whole numbers), and the result was a perfect, precise colour switch:
After that it was no trouble to produce some client logo pieces in two and three colours, with exactly correct switching.