It's Time to Update Open CAD File Standards For decades, the STEP file format (Standard for the Exchange of Product model data) has been the primary open standard for exchanging 3D CAD data across different software platforms. While STEP was an achievement that enabled CAD interoperability, it has some major limitations that are becoming increasingly problematic in our modern CAD ecosystem. BREP topology, Karl D.D. Willis The core issue with STEP files is that they only contain the final boundary representation (B-rep) geometry information - the surfaces, edges, and vertices that make up the 3D model. What STEP files lack is any record of the design intent and explicit modeling operations used to create that geometry. Information about features like fillets, chamfers, holes, and the parameters that define them is lost when exporting to STEP. This data deficiency means that when a STEP file is imported into a different CAD system, it can only see the dumb solid geometry, not the rich feature-based history and intelligence that went into creating that model. As a result, the imported model is essentially a static solid that can't be easily edited in the new CAD environment using synchronous modeling techniques. Benjamin Jones et al., B-rep Matching for Collaborating Across CAD Systems Companies like Onshape have tried to work around this limitation by using machine learning to reverse engineer the modeling operations from just the B-rep geometry data. But having to rely on best-guess algorithms is not the way to go when the CAD software we are exporting from contains this information all along! The reality is that in 2024, we need an open CAD file format that goes beyond just B-rep geometry to also capture and exchange the complete design data model - the features, parameters, constraints, and modeling operations that describe how the part or assembly was actually built. This remastered CAD file standard needs to enable true interoperability where intelligent, scalable, re-usable CAD data can be seamlessly shared across systems and teams. Some of the largest CAD vendors like Autodesk and Dassault have already started developing more robust data exchange methods. But there remains a dire need for a new open source data standard owned by the broader CAD community versus propriety incumbents. Example Cadquery code, chain of event history and parameters There are already parametric frameworks like CadQuery that provide a schematic for obtaining a design chain history. However, the key issue is achieving mass industry adoption to the same extent as STEP for export options. This adoption will be challenging because companies may be reluctant to reveal their design histories, which they have obfuscated. One solution is to write plugins for all major CAD software to extract the chain of events, if possible. Standards bodies that developed STEP should spearhead this effort to define a next-generation open source data model for CAD that brings manufacturing interoperability into the modern age. Our industry's continued innovation depends on it!