Migrate from ARCHICAD 17 and earlier.
The Building Materials dialog box has a “Participates in Collision Detection” checkbox in the Properties panel. This is useful for defining whether particular building components - parts of composite or complex elements - should be exported in IFC, and/or whether they should participate in collision detection.
See Collision Detection.
All Building Materials are migrated with the checkbox ON. (In other words, all migrated Building Materials are set to participate in Collision Detection by default.) To exempt any Building Material, uncheck its box in the Building Materials dialog box.
Relevant topics
Collision Detection Enhancements
The Collision Detection feature, introduced in ARCHICAD 21, has been further enhanced:
• New Volume and optional Surface ...
Collision Detection
Use this function to identify collisions among 3D elements in the model. A collision occurs when two or more elements physically intersect.
...
Building Materials (Attribute Manager)
(Parent topic: Attribute Manager: Editable Attribute Parameters)
Select one or more Building Materials.
•Edit Name (single selection ...