Question about compatibility with other geometries

[Podolsky]

ArchiCAD has quite good imports from another 3D packages. But all of them are coming as library part objects (tool that has chair icon). Later you can explode them (if you want) into editable morph tool - that is some sort of native 3D mesh.
If talk about ArchiCAD mesh tool - that is designed for landscape purposes, you cannot convert imported geometry into it.

[furtonb]

It also depends on your Rhino geometry - if you are familiar with Grasshopper, there is a plugin developed by GRAPHISOFT that lets you generate native Archicad elements: https://graphisoft.com/downloads/addons/interoperability/rhino

This also assumes some knowledge about what are the boundaries of each tool in Archicad, but for most you should be covered.

[runxel]

Regarding topography:
Archicad can read in surveyors data (xyz files).
If you already have the topo data lying around you can just use that.