Collision Detection

Use the MEP Collision Detection function to identify places in the project where MEP elements intersect with each other and with other construction elements.
Issue the Design > MEP Modeling > Find Collisions command. This command is available in the Floor Plan and 3D windows.
The Collision Detection information appears.
Click Show Mark-Up Tools to open the Mark-Up Tools Palette, if it is not open already (from Document > Mark-Up Tools).
Now you can use ARCHICAD’s Mark-Up function to highlight and zoom to the Collisions, make edits or add Mark-Up notes as needed.
Note that once you correct a collision, you should delete it from the list of Mark-Up Entries. Otherwise, the next time you run the Collision Detection, ARCHICAD will continue to list the corrected collision as a “problem area.”
See Mark-Up in ARCHICAD Help for details.
Which Elements Participate in Collision Detection?
Collision detection is based on Element Classification (Categories and Properties), not on ARCHICAD tool type. As a result, collision detection works on:
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all imported IFC MEP elements (regardless of which MEP application exported the IFC model), and
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all ARCHICAD project MEP Objects and MEP-classified elements (for example pipes defined with Beam tool, but classified as MEP elements).
If any MEP elements are selected, Collision Detection will be restricted to the selected MEP elements.
If nothing is selected, Collision Detection will review all elements classified as MEP-type in Element Settings (Categories and Properties > Element Classification).
The collision detection function works between solid and solid and between solid and open shell geometries, and includes qualifying elements which are part of Modules or Groups, and which are located on locked layers.
Collision Detection does not include non-visible elements (those on hidden layers).
Collision Detection also takes the elements’ Building Materials into account: Building Materials in ARCHICAD (Options > Attributes > Building Materials) have a tag for “Participates in Collision Detection”. This checkbox is on by default.
However, if it is turned off, then it will not participate in the MEP Collision Detection. This can be an advantage. For example, a Composite Wall can include the Air Space Building Material. The HVAC system can be built in to this skin. If that Air Space Building Material is defined with the Collision Detection checkbox set to “Off”, then no collision occurs.