NIST STEP File Analyzer and Viewer

The National Institute of Standards and Technology (NIST) has developed the STEP File Analyzer and Viewer (SFA). The STEP File Viewer supports parts, assemblies, dimensions, tolerances, and more. The Analyzer generates a spreadsheet of all entity and attribute information; reports and analyzes any semantic PMI, graphic PMI, and validation properties for conformance to recommended practices; and checks for basic STEP file format errors. All commonly used STEP file formats, also known as Application Protocols (AP), are supported.

The STEP File Analyzer and Viewer can be downloaded from NIST or GitHub.

STEP File Viewer

The STEP File Viewer displays many features of a STEP file in a web browser.

• Part with graphic PMI for geometric dimensioning and tolerancing (GD&T), including saved view viewpoints, datum targets, and sketch and supplemental geometry
• Box assembly including sketch geometry
• Bracket assembly with Bill of Materials
• Section view clipping planes
• AP209 finite element analysis models

STEP File Analyzer Spreadsheets and Reports

A spreadsheet simplifies analyzing information from the STEP file at an entity and attribute level. In a spreadsheet, each entity type is a worksheet and each row is an entity instance where the columns are the entity attributes.

Three types of reports, based on Recommended Practices defined by the CAx Implementor Group, can be generated.  Semantic PMI (aka PMI Representation) represents dimensional tolerances, geometric tolerances, datum features, and more. It is computer-interpretable to facilitate interoperability with other CAD systems and with downstream applications for manufacturing, measurement, inspection, and other processes. Graphic PMI (aka PMI Presentation) consists of the exact visual appearance (lines, color, position, orientation) of the GD&T annotations. It is not intended to be computer-interpretable and does not carry any representation information. The Viewer displays the graphic PMI. Validation Properties are quantities related to features of a CAD model that are computed by the native CAD software used to validate the import of those quantities into another CAD system. 

This spreadsheet was generated from an AP242 file with reports for semantic PMI, graphic PMI, and validation properties. Results are color-coded based on one of the NIST CAD models.

This spreadsheet was generated from an AP203 file that contains graphic PMI and validation properties. 

This spreadsheet  was generated when processing multiple STEP AP242 files. The File Summary worksheet shows the distribution of STEP entities across all of the files. The Coverage Analysis worksheet shows coverage of semantic and graphic PMI concepts from the STEP file and CAx-IF Recommended Practices.

Syntax Checker

The syntax checker checks for basic syntax errors and warnings in the STEP file related to missing or extra attributes, incompatible and unresolved entity references, select value types, illegal and unexpected characters, and other problems with attributes. Syntax checking might help you diagnose errors when importing STEP files into CAD software. STEP file errors should be fixed to ensure that the file conforms to the STEP schema and can interoperate with other software.