One of the most stressful things for a consultant/contractor in the BIM world is getting a clash report after the coordination meeting that shows hundreds of clashes that need to be fixed “soon”.
To avoid this stressful situation, Navisworks provides us a really smart tool to group clashes based on objects that will eventually be changed. By grouping clashes, we not only reduce the total number of clashes displayed in the report, but also provide the consultants a better way of fixing all the clashes related to a particular item, before proceeding to the next item.
The following is the procedure for grouping the clashes.
- Run the clash test (I prefer running my clashes based on search sets, but that’s a discussion for another day).
- Click on the Results tab, as shown in Figure 1.
Notice that the clashes are displayed ungrouped right now. Also, as shown in Figure 2 below, the total number of clashes is 34.
To group the clashes, there are two buttons (called Group Clashes Involving Items buttons) available in the Item 1 and Item 2 area, as encircled in the figure above. The big question is whether you click the button in the Item 1 area or the Item 2 area. This is where you need to think about the object that will be changed. As see above, this clash is between Structure and HVAC. To resolve these clashes, it is the HVAC items that you will move and not the Structural items. Therefore, you will click on the button in the Item 2 area as that area represents the HVAC items.
- With a clash highlighted in the Results area, click the Group Clashes Involving Items button in the Item 2 area; all the clashes that the selected duct is involved in are grouped together, as shown in Figure 3 below and the total number of clashes comes down from 34 to 32.
- Similarly, click the next clash and then click the Group Clashes Involving Items button in the Item 2 area again; all the clashes that the selected duct is involved in are grouped together, as shown in Figure 4 below and the total number of clashes comes down from 32 to 30.
- Similarly, repeat this process for the rest of the ungrouped clashes. Note that you will notice that when you group some of the clashes, there may be some items that are only involved in a single clash. In that case, you can explode that group by clicking on the Explode Group button available on the left of the Assign button above the results in the Results
Now, once you have grouped all these clashes, it is extremely important that you select the right option while generating the report.
- While generating the report, make sure you select Everything from the For Clash Groups, include list.
Hopefully, by reducing the total number of clashes and also grouping them in a logical manner, you will make it easier for the consultant to fix them.