I would like to make a suggestion to the developers of revit. Many cities (if not all) across the world have building zoning in place. I'm sure you know what that is so I won't go into much detail explaining. I am from Cape Town and we are allowed to vertically divide the site up and calculate the zoning as per the divided areas.
Imagine a cake ( as the maximum size your building can be which the zoning and site shape will allow, in Cape Town the height of the bottom of which is calculated by taking the highest and lowest points on your site and finding the average height of the two points eg. If your highest point is at 10m from sea level and the lowest at 5m from sea level the base level will be at 7.5m from sea level ).
If you cut the cake (with a vertical divide) you can have 2 base levels, cut it again and you can have 3 base levels, etc etc.
The heights of the now cut up cake 'slices' are then calculated using the highest and lowest points (as explained above) but for each vertically divided area within the site.
So what I would like to suggest to you, the developers of revit, to introduce a vertical divide system into the already in place conceptual mass function that will allow you to move the 'slices of cake' to the new heights and that the vertical divides, when moved will will cut the mass in a different place and thus the mass will change which can then move to their new heights.
