Why do we insist on not using ODA? Unveiling the underlying logic behind 100% lossless extraction of BIM model data!

3DExpert: Expert in 3D/Bim/GIS Model Data Processing, High-Performancerendering

Lightweighting, and Rendering Technologies. In a market where 3D/BIM lightweighting and application platforms are flourishing, a critical yet often overlooked issUe is quietly impacting user experience: Are model data being transmitted—completely and accurately—from the original design software to the lightweight rendering engine or application software system?

Many users may have already noticed that when opening proprietary-format models—such as .rvt, .dgn, .nwc, or .sldprt—using certain “general-purpose” 3D/BIM model viewers, components often go missing, materials become misaligned, attributes are lost, and sometimes even entire floors seem to “disappear into thin air.” These issues are not accidental; rather, they stem from the inherent limitations of the Open Design Alliance (ODA) framework underlying these viewers when dealing with complex 3D/BIM models.

As a specialized vendor of 3D/BIM/GIS model data processing technology, 3DExpert has chosen a more challenging yet more reliable technical path: abandoning ODA and independently developing dedicated export plugins based on the official APIs provided by CAD vendors, thereby ensuring 100% lossless extraction of geometric, texture, material, structural tree, and attribute data from mainstream design software such as Revit, Bentley, Navisworks, and SolidWorks.

Why does the ODA scheme “seem convenient” yet actually harbor numerous hidden risks?

ODA is a third-party middleware library designed to enable cross-platform reading of proprietary file formats—such as .rvt and .dgn—from vendors like Autodesk and Bentley—by reverse-engineering these formats. Its key advantage lies in its “single codebase that supports multiple formats,” resulting in low development costs and rapid time-to-market. However, in real-world engineering scenarios, ODA’s shortcomings are laid bare:

● Random loss of model components: Particularly in large-scale MEP, steel structure, or irregularly shaped building models, some family instances, nested components, or parametric objects may fail to be correctly identified.

● Incomplete attribute information: Shared parameters, custom fields, and classification codes (such as OmniClass and Uniclass) are often overlooked or mapped incorrectly.

● Material and texture distortion: Support for advanced rendering attributes such as PBR materials, transparency, and texture coordinates is limited.

● Poor version compatibility: Whenever Revit or Bentley releases a new version, ODA often lags by several months before it can be adapted, during which period new feature models cannot be read properly.

In the course of serving our clients, the 3DEx expert team conducted comparative tests using real project models collected from actual projects. The results were alarming: over 68% of Revit models exhibited varying degrees of data loss under the ODA scheme, with 12% of these models suffering data loss rates exceeding 15%. For users who rely on precise 3D/BIM data for construction simulation, clash detection, or operations and maintenance management, this represents an unacceptable risk. 3DExpert’s Choice: Doing the Right Thing the “Hard Way”。

Faced with the industry’s widespread adoption of the shortcut approach of ODA, 3DExpert resolutely invested substantial R&D resources to develop, for each mainstream 3D/BIM design platform, a dedicated export plugin based on the official APIs:

● Revit plugin: Deeply integrated with the Autodesk Revit API, it provides direct access to the Document object model, allowing you to iterate through all data—such as geometry, materials, parameters, views, phases, and worksets—component by component.

● Bentley plugin: Utilizes the MicroStation CONNECT SDK and the OpenBuildings Designer API to precisely extract Cells, SmartSolids, Item Types, and their associated attributes from DGN models.

● Navisworks Plugin: Parses aggregated models, state animations, annotations, and clash results from NWD/NWC files using the Navisworks Automation API.

● SolidWorks Plugin: Use the SOLIDWORKS API to obtain assembly hierarchy, configurations, feature tree.

Core Advantage: Bypass file parsing and directly connect to the memory data structures of design software. This means that 3DExpert obtains not “retranslated, secondhand information,” but rather a first-hand, complete, real-time snapshot of data created by designers in the original environment.

100% lossless—not just a slogan, but the cornerstone of engineering reliability. With the support of 3DExpert model data processing technology, users can achieve:

✅ No components missing: Even a single bolt, cable, or door and window family is completely preserved.

✅ Full attribute inheritance: Includes IFC attribute sets, COBie data, custom parameters, classification codes, and more;

✅ High-fidelity visualization: Accurately reproduces effects such as PBR materials, transparent glass, and metallic reflections.

✅ Consistent structure tree: Views, floors, and system categories in the project browser are fully synchronized with the web end.

✅ No version worries: Automatically adapts in sync with official updates from Revit, Bentley, and SolidWorks—no need to wait for third-party libraries.

A large-scale airport BIM operations and maintenance platform project once experienced a 30% loss of valve models in its HVAC system due to the use of the ODA solution, leading to incorrect equipment positioning in later stages. After switching to the 3DExpert technology solution, over 120,000 components from all disciplines were loaded completely at one go, with an attribute matching accuracy rate reaching 99.98%, thereby completely resolving the data fragmentation issue.

Conclusion: True 3D/BIM model processing and lightweighting begin with a deep respect for data. Model data processing and lightweighting are not about “compression” or “simplification”; rather, they aim for efficient transmission and accurate rendering while ensuring the integrity of the information. 3DExpert firmly believes that the value of 3D/BIM models lies not in how dazzling their visual presentation is, but in how precise their data is.

Precisely for this reason, we’d rather spend more time developing dedicated export channels for each mainstream design platform; and even though it means bearing higher R&D costs, we’re determined to uphold the bottom line of “100% lossless” at all costs. Because for engineers, missing even one component could mean a rework; losing just one attribute could lead to a misjudgment.

Choosing 3DExpert’s 3D/BIM/GIS model processing technology means opting for the utmost respect of the original design intent and absolute assurance of the authenticity of engineering data.

Don’t take shortcuts—stick to the right path. Let every piece of 3D/BIM data be truly trustworthy.