(Migrate from ARCHICAD 20 or earlier)
Some Library Parts in ARCHICAD 21 now use Building Materials and/or Profile attributes, instead of Surfaces and Fills. These upgraded Library Parts can be found in the Basic Library/Building Structures folder, as well as the Add-on Library/RoofMaker Library folder.
Library Parts using Building Materials do not participate in automatic, priority-based connections.
The older-version counterparts of these Library Parts (if you placed any into the project) are not migrated to ARCHICAD 21. The upgraded Library Parts are loaded into the project from the Migration Library, when you use the Consolidate Libraries command.
For details, see Migrating Libraries to ARCHICAD 21.