by Dennis Collin
A consultant recently asked me, how they could see the differences between 2 recently issued Revit models. The revision changes notes just had a description saying ‘model updates’. There are a few ways to do this, but one method is to utilise one of the tools within the AEC collection, Navisworks. Navisworks is a software solution to allow users to perform all kinds of tasks relating to coordination, including visualisation, construction sequence, clash detection and changes in data. Navisworks also can read in many file formats and save them into an optimised NWD format which is ideal when working with large complex models.
To bring these Revit files into Navisworks. Start a blank file and bring the first model and second model in via the append to model function. Hopefully their origins should be identical, and the model should import at the same location, on top of one another. This can also be done with other file formats like NWC, NWD, IFC, Catia, Obj Microstation etc.
For a list of support formats go here:
Fig 1. Use the Append tool to bring models of different formats for coordination or comparison purposes.
Within the Home tab, access the Tools panel and select the Compare function. The compare tool will be greyed out until two items are selected for comparison. If this is the case, select both items from within Navis' Selection Tree. It is also possible to navigate the tree and compare components at individual selection level.
Fig 2. The selection tree can be used to define model or model parts for display or comparison.
Once selected, a dialog box provides display options for comparison. This can be changes in geometry or element properties. For clarity of the results users can choose to hide matched elements and highlight differences.
Fig 3. Once some elements have been selected in the Tree, the Compare command becomes accessible.
Ensure that the Overridden Material and Overridden Transform options relate to changing the colour and transparency in Navisworks, and changing a file's origin, scale or rotation since loading into Navisworks, respectively. These options are unticked by default, with all other criteria relate to the properties of elements from the original model.
Fig 4. Compare display options can be configured and set from the Appearances command.
The compare function then displays the two models in different colours so that changes can be identified in the two models. In this example red highlights where changes have been made, magenta indicates addition of new elements with yellow items being unchanged. These can be saved into Selection sets for easy recollection.
Fig 5. Model changes can be colour coded and saved to selection sets if required.
There are other methods for model change comparison, these will be discussed in future posts.
For more information on Revit and Navisworks talk to one of the team at Arkance UK where we can discuss your needs.
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