Not so simple, dear Laci!
If the mesh is generated by ArchiTerra, it stores some important user data so if you split it into different parts these data will be lost (or better only one part of the mesh will still continuing to store them).
Instead of workaround the trouble by splitting the mesh (that is a very smart trick because ArchiCAD during/after the splitting elaboration usually fixes also the minor troubles) usually I prefer to look for the trouble and finding the solution… for this reason I asked for the project.
Usually when this trouble appear they come from “degenerated” mesh and not from the complexity: if ArchiCAD has to calculate very complex mesh usually it slows down and takes a lot of time to elaborate it but it doesn’t crash. If ArchiCAD crashes this means that the mesh is, in some way, damaged.
Friendly
Fabrizio
Fabrizio Diodati
Graphisoft Italy Srl | Via Rossignago 2/A Spinea Venezia 30038 Italy