We use Autodesk Navisworks almost exclusively as our primary clash detection tool. However, up until about a year ago, we have only worked with “projected” models – that is, shop drawings in 3D format that convey what the project will look like once that particular system is installed. Combining all of these files into Navisworks usually results in what's known as “clashes”, or conflicts between systems where certain elements are competing for the same space.
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Thanks to the recent proliferation of point clouds in the AEC industry, we have been able to add in point cloud files as an additional format to our clash detection efforts. There's a couple significant reasons to import a point cloud file into your coordination model:
1. Existing space verification.
If your project is an interior build-out, an addition to an existing building, or parked very close to an existing structure, having a point cloud of that existing context is a huge help inside Navisworks as a means to verify how close your models are to existing elements. This is also useful to confirm your architectural and structural models are correct (or in some cases, a little off).
2. In-progress as-built verification.
A in-progress point cloud is catching on as a very useful way to determine just how close the aforementioned shop drawing models compare to the work put in place. Although I'm still describing an “as-built” point cloud, the timing of this scan is the important distinction. An in-progress scan is done the moment MEP subcontractors begin installation with subsequent scans happening thereafter to monitor progress. Although Holder has only deployed this method a few times, this is an exciting avenue we're hoping to do more with in the future.
Zack Creach is a senior engineer for Holder Construction in Atlanta.