First I would look for an existing object and hope that it is parametric enough to do what you want.
If not then you can convert to a morph and try editing that, but larger complicated morphs can be a bit painful to edit sometimes.
Otherwise create it from walls, slabs roofs and possibly simple shaped morphs (that are easier to edit).
You can then GROUP all of the elements so they stick together.
You could save as an object (although it won't be parametric) or save as a module (.MOD file) for use in other projects.
The ultimate of course is to script your own parametric object, but if you are not familiar with GDL scripting I would not attempt this.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11