Clash Detection with Reality Capture (Point Cloud) Data

This post of mine appeared in the ReCap Product Blog some time back, but thought of posting it here as well.

Reality capture is becoming an important part of the overall strategy in any major BIM/Infrastructure project. More projects now involve reality captured point cloud data of the existing state that needs to be considered while designing new buildings or infrastructure. Autodesk Navisworks plays a big role in this process by allowing the design consultants to perform clashes between the existing (captured as point cloud) and new design.

In this post, I am going to show a step by step procedure of performing clashes with Autodesk ReCap point cloud data and solid ducts in Autodesk Navisworks. If you would like to follow along, you can download the required file by clicking here. Note that you will need Navisworks Manage 2016 to perform clashes using these files. If you use Navisworks Manage 2015, please contact me and I will share the 2015 version files with you.

1. Open the Scan-Clash.nwd file; the Autodesk Navisworks file opens with the point cloud data and the ductwork, as shown in the figure below:

2. Activate the Clash Detective window.

3. From the top right corner of the Clash Detective window, click the Add Test button; the Tests panel is expanded and a new test is added to it with the default name of Test 1.

4. Rename the clash test to Duct V Point Cloud.

5. From the Selection A area in the Select tab, click on the Standard list and select Sets; the four sets created in the Autodesk Navisworks scene are displayed.

6. Hold down the CTRL key and select the Ducts-Side1 and Ducts-Side2 sets.

7. From the Selection B area, click on the Standard list and select Sets.

8. Hold down the CTRL key and select the Voxels-Side1 and Voxels-Side2 sets. (The point cloud is automatically broken down into smaller voxels).

9. From the toolbar at the bottom of the Selection B area, click the Points button. This is the key. If you do not select the Points button, you will not be able to perform clashes with the point cloud data.

10. In the Tolerance edit box, enter 0.04 Inches or 0.001 Meters as the value, depending upon your display units.

11. From the Type list in the Settings area, select Clearance. This is the type of test that you need to run to perform clashes with point cloud.

12. Various clashes found are displayed in the Clash Detective window, as shown below. You can review various clashes and see where those clashes are. 

Tip: If required, you can use the Report tab to write a report with these clash results. I prefer using the HTML Tabular format while writing the report.