The STEP AP203 and AP242 files were generated from the CTC and FTC CAD models used in the 
NIST MBE PMI Validation and Conformance Testing project. https://go.usa.gov/mGVm

The STEP files were generated by different CAD software and might not represent the current
capabilities of that software.  Information that shows which CAD software generated the
files has been removed.

The '_ap203' and '_ap242' files have graphical PMI.  The '_ap242' files have semantic PMI.
The other STEP files contain only part geometry.  

AP242 files are identified by '_ap242-e1' or '_ap242-e2' for the edition 1 or 2 of AP242.
Edition 1 was published in 2014 and edition 2 was published in 2020.

FTC 8 also has a file '_ap242-e1-tg' where the part geometry uses tessellated (faceted)
surfaces instead of exact b-rep geometry.  There is no semantic PMI in this file.

Your CAD software or STEP viewer might not support graphical and semantic PMI.  Use the
STEP File Analyzer and Viewer to view the graphical PMI and to analyze the semantic PMI.
https://go.usa.gov/yccx

The semantic PMI analysis for the AP242 files will be color-coded by the expected PMI.
See Help > Analyze > NIST CAD Models

These are NOT reference STEP files without any errors.  The STEP File Analyzer and Viewer
will report some Syntax Errors.  Other conformance checking software might also indicate
that the files have some errors.

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March 2024 Update

AP242 files from the STC CAD models have been added.  The STC are based on the FTC with
less complex PMI.  Most of them are based on AP242 edition 3 which was published in 2022.
