Rarely are BIM models created by a single entity in a vacuum but are usually the conglomeration of models built by many companies contributing to a single goal. Using the models from the different trades to identify clashes, and other issues, is one of the main strengths of Building Information Modeling and the intent of the 3D coordination process. When managing the coordination of the contributing models a project requirement is often to submit the models on a per floor basis – one model for each floor of the facility. While this may be a good idea in regards to furniture plans or the layout of demising walls, the building envelope, especially curtain wall, is rarely created as single floor model for many reasons including: It would be less efficient, the upper and lower components of the stack joint rarely align with the top of slab, and the number of wall models created would be multiplied by the number of floors. In this exercise we will look using section boxes to accurately export single floor models for BIM coordination in Navisworks.
Section boxes only appear in 3D views but, surprisingly, the first step to creating the section box to isolate a floor in a 3D view is to create a new elevation. Open the floor plan for the level that you want to create the model for, then add an elevation perpendicular to one of the external walls.
Double-click the elevation head in the plan to open the new elevation view then make sure the crop region is displayed and that the Crop View option is selected in the View Control Bar at the bottom of the view.
Select the Crop Region to display the segment handles then move the top and bottom segment handles until they snap to the levels that bracket the floor that you want to isolate.
Create a new, or duplicate an existing, 3D view and make sure the Section Box option is checked in the Properties palette.
Right-click on the Viewcube then chooses Orient to View>Elevations then select the elevation in which you modified the Crop Region.
The 3D view is adjusted to match the elevation that you created at the start of the exercise.
Change the orientation of the 3D view then select the Section Box to expose the control handles.
Carefully select and move the control handles on the four sides of the Section Box but make sure you do not change the position of the handles on the top or bottom of the Section Box.
From the Application button, choose Export > NWC then save the new .nwc file. Revit will create the new Navisworks file. If the project coordination is being performed in Autodesk Glue 360, you would choose Add-ins > Glue to initiate the export process..
Open Navisworks then navigate to then open the file you just created. The file opens showing just the floor that you isolated with the Section Box.
Using the technique shown here can effectively create the single-floor models required for the coordination process without the need to create many single-floor models. To generate isolated floors for the remainder of the building, simply repeat the steps shown above.