Fabrication Collision Detection

July 1, 2021 Heather Volk

Utilize basic collision detection from within Fabrication to see where you have clashes. You can use the collision detection as it applies to the design line.


  1. Enable the collision check feature. Main Database > Takeoff > CAD Settings > Collision Check:

  1. Draw in services using Design Line. Each service will be its own design line.

  1. If a Design Line crosses another and causes a collision it will give you a warning once drawn in 3D. This is a Return Air line that is crossing over a CWS line. The Return Air has not been drawn in 3D yet.

  1. Return Air drawn in 3D will acknowledge the collision. As soon as “Fill in 3D” happens a pop up indicates the collision:

  1. The error lists the items, sizes, and elevations. Select the “Mark Collisions” box to mark them in model space. Select the “Isolate Selected Objects” to isolate the collision to resolve the issue.

  1. Adjust the items to fix the collision as needed.

  1. Select the “Show All” button to turn everything back on:

  1. “Delete 3D” to remove all items from design line, select “Fill in 3D” to redraw with new location.


You do not need to use the Design line to use the Collision Detection feature. The same results can be achieved while using the attacher method of drawing as well. Design line (if set up properly) can save much more time when drawing.

About the Author

Heather Volk

Sr. Technical Support Specialist, Building Solutions<br><br>Heather is responsible for responding to customer requests and helping them address technical challenges in a timely manner. She is an experienced Computer Aided Design Manager with a demonstrated history of working in the construction industry. She has strong arts and design professional skills in AutoCAD, plumbing, computer aided design (CAD), project estimation, and facility management, and a history of providing training and technical support.

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