OpenDesign Alliance's BimNv SDK is a software development kit for dealing with Navisworks files and was developed independently of Autodesk.
About Navisworks from Autodesk
Navisworks is Autodesk's universal file format for viewing project files made with multiple software programs, such as AutoCAD, Revit, and Inventor, as well as neutral file formats (like IFC, STL, and PDF) and proprietary ones, such as Pro/Engineer, Solidworks, and MicroStation. (See figure.) For more info on formats, see knowledge.autodesk.com/support/navisworks-products.
For instance, you are designing a building with Revit that contains a machine designed in Solidworks, all on top of topology from a point cloud (Recap). To view how it all fits together, the individual models are loaded and coordinated in Navisworks, from which clash detection, markups, project progress, and so are performed. (See figure.)
The native file formats of Navisworks are as follows:
NWD - contains all the models in a single, compressed file
NWF - contains links to model files, plus markup data
NWC - cache files created when an NWD file is opened, to speed up subsequent loading
When an NWD file is opened, it uses external file readers to view the different file formats; you can substitute your own readers, as the ones provided by Autodesk do not necessarily support all entities. The Autodesk Developer Network offers an API to members ($1,400 and up) for writing add-ons to Navisworks, as well as exporting data out of Navisworks.
ODA's Navisworks SDK
The ODA has its own version of a Navisworks SDK that it has named BimNv. The SDK [software development kit] allows programmers to write software that works with Navisworks files. An SDK includes APIs [application programming interfaces], which programs use to make calls that read and process data in the Navisworks files. The ODA says its API is similar to that of Autodesk's Navisworks API. The SDK is available only to Sustaining ODA members or higher ($5,000 and up).
Neil Peterson, the president of ODA, tells me that he sees three kinds of organizations that might prefer using BimNv over Autodesk's SDK:
- Those wanting to view and import Navisworks models in their own desktop software without having to depend on Autodesk software
- Those wanting to visualize and access Navisworks models on the Web without having to use a third-party service like Autodesk's Forge
- Those wanting to export Navisworks models from their applications with no dependencies on Autodesk software.
For example, some government agencies in Australia are mandating the use of Navisworks for certain civil projects, and so the ODA has members looking to BimNv for integrating an Navisworks export function into their products.
The ODA held a Webinar this week on the progress is is making with BimNv API, explaining that it really is a work-in-progress.
BimNv supports NWD, NWF, and NWC files from 2013 and newer. Older formats (2009-2012) are also supported but not as well, because, as they explained, "It is hard to find many Navisworks files from 2009 for testing purposes." Currently, the focus of ODA programmers had been on reading the format, and they have completed some initial editing functions of NWF files.
Navisworks contains data from many programs, so if ODA has already documented one of them, like DWG, then it is OK; if not, then it is more difficult for the ODA to support the data. So, designs made with DWG (AutoCAD and workalikes), DGN (Microstation), DXF, RVT (Revit), and IFC have "excellent" support.
To view Navisworks-style files, ODA offers its Visualizer Viewer (see figure). To view the files, ODA converts them to its own VSF format (Visualize Stream Format). The viewer handles the following functions (among others):
- Cutting planes
- Multiple models in one viewer
- Save to DWG (quite large, as DWG has to represent everything)
- Export to PDF (when the ODA's Publish SDK is added) and OBJ
Autodesk has no Navisworks viewer for mobile devices, although third parties have viewers that export NWD files to their own viewer's format. So it turns out that the ODA's OpenCloud is the only way to view Navisworks files on mobile devices, through cloud.opendesign.com (see figure).
Mobile viewer from ODA (source: ODA)
What's Next for BimNv
The ODA's programmers are working on exporting VSF files to Navisworks format, reading the clash elements that are stored in Navisworks files, and support for sheets.
Q: Are PDF files exported from Navisworks files in 2D or 3D?
A: Both, as they is generated by the Visualize SDK.
Q: Has Autodesk a Navisworks viewer for mobile?
A: No. Navisworks files tend to be large as they combine many formats, and so there may be issues loading them on mobile devices. With Autodesk, there are third-party plug-ins to convert the format and then view the files on a mobile devices.
Q: Does BimNv have any accessible BIM data in it?
A: Yes, we can contain data in the file as BIM data, such as those from Revit converted to Navisworks format. Here, some Revit properties are retained, such as colors, categories, and so we can access that data.
Q: Can it visualize without the Visualize SDK?
A: You would have to create your own viewer, such as with your own MSC or Qt application.
Q: Is rendering single-threaded?
Q: Any plans for multi-threading?
A: Yes, but the priority is not high right now. Visualize SDK could handle multi-threading external to Nv but some output need may to be internal to BimNv.
Q: Is the loading single-threaded?
A: We have both, single- or multi-thread, so you can switch.
Q: Is a trial version of BimNv SDK available?
A: It is available in trial format for Windows only, which is sufficient for concept.