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 project for its revision and review but doesn’t allow you to edit.
Navisworks has three file formats as follows:
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.
You will need to consider how you are going to build the model. Below is the process we should follow to prepare the models to work correctly.
Consider the location of the 0.0 of the project in the models of the different disciplines, so that when they are inserted they are in the correct position, outside of which one can move and accommodate it, although I don’t recommend it as this could bring coordination problems.
Ensure you define, amongst all those involved, the work units so everything is 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 analyse the possibility of subdividing it before exporting. This is done to make clash detection easier, more limited, and with more manageable report generation.
One of the objectives 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 you then 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.
All these points must be defined with all those involved in the project in the BEP (BIM Execution Plan); since in it we define the tasks and the processes of exchange of information.