Is there a way to shave one toposolid from another?

[MiWolff]

I have three bits of terrain: the first being the base topography or the pre-project landscape, the second everything that needs to be added to the existing landscape and the third showing what needs to be removed from the existing situation to allow the project to be built. While I seem to be able to subtract one toposolid from another or add one, there is no way to xor a toposolid or is there? How can this be modelled? I have csv files of the three topographies.

[arq_42 · Accepted solution]

You need to create an existing toposolid in the "existent" creation phase.

Then, in the current creation phase, select the toposolid and use the "Create Graded Region" button.

Massing & Site tabModify Site panel (Graded Region).

You must make the modifications to this second toposolid that will be created, so that it has its final appearance.

Then you can generate schedules with the added and removed soil, all related with the original one.

help.autodesk.com_GRADED REGION 

[MiWolff]

There is a median topography that is a copy of the existing material which is in turn edited with all the tools like importing points available.

[MiWolff]

Having watched a video on how to do this, I find that Revit 2025.4 does not have an import option when fiddling with the sub-elements.

[MiWolff · Accepted solution]

Sorry for getting anybody's hopes up. I retract my earlier acceptance. There procedure I followed was for toposurfaces and not toposolids. As toposurfaces seem to be sufficient for my purpose, I have now reverted to an older pre-toposolid version of revit.