Research

Why manufacturing AI cannot understand a part from STEP alone

Subduxion Research · September 16, 2026

A 3D model can describe the shape of a part with extraordinary precision. That does not mean it describes how the part should be manufactured.

A STEP file is not inherently geometry-only. Modern STEP AP242 can carry product and manufacturing information (PMI), such as dimensions and tolerances, alongside geometry.12 The practical problem is that the files manufacturers actually receive often contain only part of the information required to decide how a component should be made: geometry may arrive in one file while tolerances, surface requirements, material specification and engineering notes remain in a separate PDF drawing.3

That distinction matters once software is expected to do more than visualize or recognise geometry.

Recognising a hole is not the same as understanding what the hole requires. Is it clearance? A fit? Is its position controlled relative to a datum? Does it require a secondary operation? Can it be produced in the same setup as the surrounding features? Geometry answers only part of that question; the requirements answer another part, and the two do not always live in the same file.

From geometry to manufacturing intent

An intelligent manufacturing system therefore needs to reason across multiple representations of the same part.

Not a direct mapping from STEP straight to price, but a longer chain: 3D geometry, drawing and PMI, material, quantity and factory context combine into requirements, manufacturing features and a candidate manufacturing route.

The system must also distinguish between what is explicitly specified, what can reasonably be derived and what remains uncertain. That is different from document extraction. It is manufacturing interpretation.

STEP is therefore not less important. Quite the opposite: model-based exchange and machine-readable PMI are crucial foundations for a more computable product definition. The difficult step comes afterwards:

What do those geometry and requirements imply about how the part can actually be made?

That is the problem Subduxion is interested in.

Notes & references

  1. ISO 10303-242:2025, Industrial automation systems and integration — Product data representation and exchange — Part 242: Application protocol: Managed model-based 3D engineering (Edition 4). International Organization for Standardization. iso.org/standard/84300.html

  2. Barnard Feeney, A., Frechette, S. P. & Srinivasan, V. (2015), “A Portrait of an ISO STEP Tolerancing Standard as an Enabler of Smart Manufacturing Systems,” Journal of Computing and Information Science in Engineering, 15(2), 021001. DOI: 10.1115/1.4029050

  3. Fischer, K., Rosche, P., Trainer, A., Barnard Feeney, A. & Hedberg, T. (2015), “Investigating the Impact of Standards-Based Interoperability for Design to Manufacturing and Quality in the Supply Chain,” NIST GCR 15-1009, National Institute of Standards and Technology. DOI: 10.6028/NIST.GCR.15-1009

  4. Barnard Feeney, A. & Thurman, T. (2023), “On Migrating ISO 10303 PMI Models to a Common Core,” NIST AMS 100-51, National Institute of Standards and Technology. DOI: 10.6028/NIST.AMS.100-51

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