sup topographic platform according to extrasagoma underground floors

[Piron88]

Good morning to all
I wanted to understand how to behave with revit when it comes to "forating" the ground for the shape of the building in case you have an extra-shaped basement ( compared to the shape of the ground floor ), since once created the topographic surface at a hypothetical altitude 0.00 m, it does not allow me to indicate as "building platform" the walls of containment of the basement that in my case are outside the shape of the ground. How does it work in these cases?
Thank you.

 

[gfrank]

the topographic surface, does not work with "tunnel" or similar effect.
the platform will have to be of the size given by the extrasagonal underground walls, the basement cover loft (extrasagoma) will have to be completed with a second superimposed loft (only layer) to which you will assign material "grass" (terrene)

 

[preben]

exact, I agree, among other things corresponds to reality, as you dig the whole building (platform) and then carry the ground over the extra shaped basement (single creation with grass material)

 

[Piron88]

Thanks guys for the tip, my problem was a procedural error finally:redface:. one last question:
the platform therefore to what could correspond to the foundation ? or to the magrone ? and in the case of an underground carraia ramp as I have to behave, since the sloped platform allows to establish a single line of inclination (when maybe in the "thick" curved ramps, the tilt line continues throughout the axis of the ramp )

 

[preben]

I believe that it agrees to make a flat platform at the lowest level, then fill the space between this and the carraia ramp with a ramp (or other element) with assigned soil or gravel material or what most suits. Let me know.