The Open Design Alliance (ODA) is one of the oldest organizations in the AEC technology industry committed to openness and interoperability. It was launched in 1998 with the objective of providing an API (application programming interface) for working with the DWG format, including opening, creating, and editing DWG files. This work is what has made DWG an open exchange standard for the CAD industry and enabled vendors around the world to develop low-cost versions of AutoCAD-like drawing applications such as IntelliCAD, BricsCAD, progeCAD, 4MCAD, etc. (See Figure 1.) Over time, the work of the ODA has expanded to support additional CAD formats like DGN and DXF, 3D formats such as OBJ and STL (for 3D printing), and BIM formats such as IFC and BCF. It has also developed dedicated toolkits for working with popular Autodesk applications such as Revit, Navisworks, and Recap.
The ODA has a conference every year to provide the industry with an update on its latest developments. I had the opportunity to attend the 2021 event that was held last week and came away with a good understanding of what the ODA does and why it is important. In addition to the technical presentations by the ODA development team, there were also presentations by some ODA member companies showing how they were implementing ODA technologies in their products, as well as a couple of panel discussions on the topics of interoperability and Scan to BIM. The highlights of the 2021 Summit are captured in this article.
A brief note, first, about how the ODA operates. It is a nonprofit organization supported by membership fees in the form of an annual subscription, and it is focused on developing technologies that can be deployed in commercial AEC applications. Thus, most of the users of ODA technologies are software companies rather than AEC professionals, although AEC firms developing custom tools can also benefit from the technologies. The technologies themselves are software libraries, software engines, chunks of code, or what is known in technical parlance as "software development kits" or SDKs. The idea is for a software vendor to use an already-developed ODA SDK to implement a desired specific functionality in their tool — for example, converting a DWG drawing to a PDF file — rather than spend the time and the resources to develop it from scratch, in exchange for a membership fee. The ODA's membership roster currently includes over 1,200 companies.
Let's look at some of the key updates that were presented at last week's event.
In addition to continuing with the development of the individual toolkits (SDKs) for specific applications and functionality (Figure 2-left), the ODA is bringing them together in a unified platform that aligns more closely with the key processes in AEC. As shown in the graphic in Figure 2 (right), this platform is represented by a circular band comprising five segments: Create, Visualize, Collaborate, Access, and Publish. In addition to serving as a useful organizational tool for its technologies, the platform helps to redefine and reinforce the main purpose of the ODA, which is now "complete interoperability for CAD and BIM."
While the platform approach allows the individual ODA technologies to be better situated in a "big picture" view, it is also helping the ODA to clarify its work and respond to requests from its member companies who, in addition to the individual SDKs, are starting to look for more integrated technologies, common workflows, and support for open standards and interoperability to build into their applications. And this demand, in turn, is coming from the end users of their applications, who are responding to the changing requirements of AEC technology that is focused more on processes rather than tools.
Let's move on to look at some of the developments in specific categories and toolkits that were shared at the Summit.
The SDKs for working with 2D drawings and 3D models are one of the oldest and most established of the ODA technologies, implemented in thousands of applications developed by ODA members which in turn are used by millions of users around the world. These SDKs are continuing to be actively developed and enhanced with new capabilities such as conversion to different formats, improved PDF export as well as import, version control, access to metadata, DWF support, support for multiple languages and fonts for text, formatting of formulas in tables, and many more.
One of the ODA members that showcased its use of the ODA DWG SDK at the 2021 Summit was a company called Microcad, which develops interior design software. Its applications were originally based on an AutoCAD engine — for 23 years! — and two years ago, the company decided to switch to the ODA CAD engine which was being more rigorously developed and featured many improvements they were looking for. Not only did the switch allow Microcad to improve the functionality of its applications and sell them at a lower cost — thus making them more affordable and helping to bring in more users — its customers did not even notice that there was any change in the engine at all. It all happened under the hood, making the transition seamless for customers without any disruption or downtime, or any change to the look and feel of the applications.
On the 3D modeling front, the ODA has its own Solid Modeler and Facet Modeler for working with complex 3D geometry. It also has a professional grade 3D visualization engine that works with any engineering application on any platform, with advanced features such as support for different visual styles, walkthough animation, object animation, view cube navigation, scene graphs to optimize rendering, global illumination, the ability to measure different parts of the model, and a mobile version for phones and tablets. All of these features are available in any client application that uses the ODA visualization engine. A demonstration of its use of was provided by ODA member IMSI Design in its TurboCAD application.
The ODA has a dedicated toolkit for working with Revit files called BimRv, covering the import, visualization, and creation of Revit models. It supports the latest 2022 version of Revit, and all older file formats starting from 2015 are automatically updated to the 2022 version when they are imported. This gives clients consistent access to the Revit data regardless of which version the model was created in. BimRv can also write files in the 2022 format. The imported models can be visualized in multiple styles as shown in Figure 5, with different materials, fill patterns, textures, and colors. Plans, elevations, and sections can be automatically generated on the fly, and used to produce documentation with dimensions, annotations, and schedules, just as in Revit. Property data for the individual elements can be explored as well as edited, and there is full support for Revit families, including the ability to create and modify attributes and parameters and create new family types. The BIMRv toolkit also includes the ability to export the model in IFC format.
Similar to the BimRv SDK, the ODA has a BimNv SDK that provides support for NavisWorks files. It works with all the three main Navisworks file formats: NWD, the consolidated file which contains all the individual models that have been imported into Navisworks for multi-disciplinary coordination; NWF, which contains references and transformation matrices for the individual models rather than the files themselves; and NWC, the cache files that are created when models are imported into Navisworks. The BimNv toolkit can access the clash collision data, testing results, markups, screenshots, animations, and other data that has been created in Navisworks in addition to the property data of individual elements. It also supports multiple visual styles, as shown in Figure 6, with improved material settings.
In addition to opening NWD files, the BimNv is also being developed to incorporate the ability to edit the property data of the individual model elements, create new viewpoints, edit object hierarchy, and make other changes, and be able to resave the models back in the NWD format.
The ODA is committed to OpenBIM, and it is a strategic partner of the buildingSMART International. Its goals are fully aligned with that of buildingSMART International, and it is an active participant in the working groups creating the different buildingSMART standards. It has a comprehensive IFC toolkit that is widely adopted by the member ODA companies to implement IFC and OpenBIM functionality in their applications, saving them from investing resources in developing these capabilities from scratch themselves.
In addition to supporting the latest IFC formats (and the upcoming 4x3 version that supports infrastructure elements), the ODA IFC toolkit includes many additional OpenBIM capabilities including clash detection and saving issues to the BCF format; support for a new validation standard called IDS that is being developed by buildingSMART to make the IFC more readable and speed up model-checking; support for the new openCDE standard for common data environments, which includes workflows for issue resolution and document exchange; support for other OpenBIM standards including mvdXML, BCF, ifcXML, ifcJSON, mvdXML; compatibility with ISO standards; and a new interpreter for the EXPRESS schema.
The toolkit also includes a free IFC viewer which supports the latest IFC formats and can validate as well as repair any errors in the imported IFC files. It can load multiple models and aggregate them in a single scene, perform collision detection as shown in Figure 7, and includes an Object Explorer to browse the properties of the individual elements.
An example of a member implementation of the ODA's IFC toolkit was presented by a company called WebInfinity, one of the founding members of the ODA. Its flagship product is a CAD application called CiView, and at the request of its customers, it implemented the capability to open IFC files and convert the entities into DWG or DXF to be able to integrate them into their projects (Figure 8). It used the ODA's IFC libraries to implement this feature.
The ODA has already developed an advanced point cloud engine that can read data from Autodesk Recap, and it is building on this work with a new Scan to BIM initiative to automate the conversion of LIDAR scan data to BIM models. We heard more about this at the Summit in a panel discussion on Scan to BIM with members from leading architectural firms sharing their perspectives on the problem. We now have a growing number of devices that can capture laser scans, including our phones, but the question of what to do with all this data remains. We need to be able to interpret it, process it, and get models out of it — it's not enough to simply import a point cloud and use it for reference in a design tool. The ultimate would be to convert a point cloud to a BIM model in the IFC format so that it can imported into any BIM application.
The ODA is also getting into the growing industry trend of managing BIM projects on the cloud with the development of an Open Cloud SDK which allows BIM models in multiple formats to be uploaded to the cloud from any device and then visualized using any browser. It also provides the necessary web-based collaboration and project management functionality such as assigning users to projects, creating issues and reports, configuring project permissions and other settings, setting up version control, etc. The ODA provides its own cloud server for hosting the files, and it also supports cloud storage on AWS or Azure.
And finally, mention must be made of the ODA's DWG extensions for vertical disciplines including Architecture (for architectural design and drafting), Civil (for landscape and infrastructure), Map (for mapping and GIS), and Mechanical CAD. The ODA Map toolkit now supports 3D data visualization (Figure 9), bringing it closer to what would be needed for CIM (city information modeling).
While all the ODA developments shared at the Summit are mostly relevant to the software developers who use ODA toolkits to power their products, it is important for end users to be aware of — and more encouraging of — initiatives like this which allows vendors to keep their costs low, making them more affordable and accessible to AEC professionals throughout the world. In addition to making economic sense, development efforts like the ODA are simply a much more efficient use of resources — why re-invent the wheel when the problem has already been solved? The AEC technology industry can definitely make faster progress in furthering the state of the art through more open and collaborative efforts like the ODA.
Lachmi Khemlani is founder and editor of AECbytes. She has a Ph.D. in Architecture from UC Berkeley, specializing in intelligent building modeling, and consults and writes on AEC technology. She can be reached at lachmi@aecbytes.com.
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