Say I have 2 objects, one with 1 cm depth, another with 0.5 cm. I want to change both to half; the first to 0.5 cm and the latter to 0.25 cm. I don’t see the proportional depth change capability?
(Usage: imagine a half sphere that is put together from 50 circles with different depth…)
Click on one and use the select all by matching depth, then change the depth
Thank you, but that does not answer the question. Maybe my English, sorry, let me reiterate. Say you have 100 rectangles, all with different depth, 0 to 1/4", Now you want to carve in 1/2" wood, so you want to double the depth of ALL of them. What can you do now? Do them one by one. I would like to select them all and say “Change depth to 2.00 times of current depth”. So all of them will be double the current depth.
if they are all different depths to start with you have no choice but to do them one at a time.
I hope that can be changed. If I would have the code of Easel, a 2 min job for me. Hint, hint Inventables 
IF by this you mean you want the gcode and do a find an replace for each of the values, then you can export the gcode by going to Project>Download gcode
But IF you mean the source code, yeah they won’t be distributing that any time soon.
What I tried to say that it is easy for them to implement.
