After you migrate a project to ArchiCAD 17 and optimize the attributes, the project will still be using the “legacy intersection method” by default to maintain junctions as per ArchiCAD 16 and before.
In Legacy Mode, the new Junctions logic in ArchiCAD 17 will not take effect in 3D. Junction methods from ArchiCAD 16 and earlier versions will be used. You may prefer this when working on an older project, to ensure that your existing intersections remain intact.
Legacy Mode is controlled in Options > Project Preferences > Construction Elements. Note that in Legacy Mode:
- the Building Material attribute is available, but the new priority-based connections will not take effect in 3D (except for Walls, where they will work as in ArchiCAD 16 and earlier versions)
- the Surfaces assigned to Building Materials are not displayed. Only element-level surfaces can be shown.
For specifics on how this checkbox affects intersections of the different construction elements in Legacy Mode, click the Info button in the dialog box.