by Garry Stockton
When considering using Navisworks there are 2 applications to choose from, Navisworks Manage and Navisworks Freedom. Manage is the most complete. It allows us to anticipate, prevent and solve interference problems of the components of the project in a virtual way. Freedom is a free viewer that allows the whole team to have access to the whole project for its revision and review but doesn’t allow any editing.
Navisworks has three file formats:
NWC file format is generated when a CAD file is opened, linked or linked with Navisworks. These are the cache files. They can also be created by exporting the model from other applications, such as Revit. When a file is first taken to Navisworks, the program automatically creates the file with the same name as the original file and in the same directory, but with extension .NWC.
These files are smaller than the original ones and accelerate access to the most used files. When you reopen or link the file, the software reads the data from the cache file. If it is newer than the original file, which means that it has been modified, it converts the updated file and creates another cache file.
NWF file format has the original native files linked, with the specific information of Navisworks brands, visualisations, comments etc. In this format the geometry of the model is not saved, that is why the size of the files tend to be considerably smaller than the .NWD.
NWD file format are files containing the full geometry of the model and all the specific data, such as revision mark-ups, properties of the objects, comments, visualisations etc. It can be considered as a snapshot of the complete model in its current state. The size of the files are considerably smaller, if we compare it with the corresponding files of original models from other design applications.
Below you’ll see the Coordination tool in Revit to help ensure your coordinates are correct.
You will need to consider how you are going to build the model. Below is the process to prepare the models:
Consider the location of the 0.0 of the project in the models of the different disciplines, so that when they are inserted they do so in the correct position.
An important issue to define among all those involved is the choice of work units, for everything to be consistent. Optimise the models before exporting them to Navisworks.
It is also advisable to create a 3D view, showing objects that you would like to export. In the case of large projects, it is possible to sub-divide the model before exporting to Navisworks. This is done to make the clash detection process clearer, limited to specific building elements and with more manageable report generation.
One of the objectives we can have is to link the models to the work schedule. Is our model ready to be able to link to that timeline? For example, suppose that the columns were modelled from the ground floor to the top floor as a single object. If then you associate the construction of that column from the ground floor, as it is not divided, it will appear built to the top floor and that is untrue. That is why it is so important to model how it is going to be built, to understand how we want to implement BIM in a project, so that we all know what is expected of the models.
The key to effective model co-ordination is to establish how the project is managed and sub-divided with the all the stakeholders on the project. Typically, the best place to record all these information exchange tasks and processes is in a BIM Execution Plan (BEP). The BEP is an important element of a Level or Stage 2 BIM project and provides a standard way for detailing the model co-ordination requirements of a project.