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Download Free CAD Models, STEP Files, and Test Results

Types of Test Cases

The FTC and CTC were part of the MBE PMI Validation and Conformance Testing Project that concluded in 2015.  The FTC and CTC are not intended to represent best practice in how to apply GD&T (geometric dimensioning and tolerancing) to a part. Simpler GD&T strategies could have been used. The test cases are intended to be valid presentations of GD&T defined in the ASME Y14 tolerancing standards, some of which may not be commonly used. 

The STC are modified versions of the FTC that remove some of the more complicated and less commonly used PMI, including all datum targets.  The STC were developed in 2023.

These test cases are used by the CAx-IF to test implementations of STEP AP242 in CAD software.

Fully-Toleranced Test Cases (FTC)

FTC-06 

PMI Validation Fully-toleranced Test Case 6

FTC-07

PMI Validation Fully-toleranced Test Case 7

FTC-08 

PMI Validation Fully-toleranced Test Case 8

FTC-09 

PMI Validation Fully-toleranced Test Case 9

FTC-10

PMI Validation Fully-toleranced Test Case 10

FTC-11

PMI Validation Fully-toleranced Test Case 11

Simplified Test Cases (STC)

FTC 6-10 have been modified to create Simplified Test Cases (STC).  The STC remove some of the more complicated and less commonly used PMI, including all datum targets.  The geometry of the STC is the same as the corresponding FTC.  STEP AP242 files for each STC are available.

Combined Test Cases (CTC)

  • CTC Definitions include sample STEP AP203 files of model geometry only and explanations of all PMI
  • STEP AP242 and AP203 files for each CTC, many with graphical and semantic PMI
  • The CTC are not intended to be fully toleranced.  CTC 02 and 04 fit together in an assembly

CTC-01 

PMI Validation Complex Test Case 1

CTC-02 

PMI Validation Complex Test Case 2

CTC-03 

PMI Validation Complex Test Case 3

CTC-04 

PMI Validation Complex Test Case 4

CTC-05 

PMI Validation Complex Test Case 5

Download CAD models

CAD Software (NIST Disclaimer)STCFTC/CTCFTCCTC
Dassault Systèmes CATIAV5-6R2023V5-6R2019V5-6R2014V5 R21
Siemens NXNX 2027NX 1980NX 9NX 8
Autodesk InventorInventor 2024Inventor 2021  
PTC CreoCreo 10Creo 10Creo 3Creo 2
Dassault Systèmes SolidWorks SolidWorks MBD 2018SolidWorks 2015SolidWorks 2012
 The STC are simplified versions of the FTC. The FTC (6,8,9) and CTC (1-5) above were verified as part of the original testing project that concluded in 2015 and documented in the Test Results below.

Modified Test Case (MTC)

This dataset is based on the project Design, Manufacturing, and Inspection Data for a Box Assembly.  The models are based on FTC-07 (box), FTC-08 (lid), and FTC-09 (plate) from above.  Those FTC test cases were remodeled to be smaller, have simpler PMI, include fasteners to join the parts, and to be more easily manufactured.  A fourth part was also added.  The parts and assembly were modeled in Dassault Systemes SolidWorks and Siemens NX 1953.

NIST MTC Assembly
MTC exploded view
NIST MTC Assembly
MTC with transparent box and lid

FTC and CTC Test Results

The verification and validation results measure PMI implementation capabilities in CAD software and derivative STEP, JT, and 3D PDF files. The results are based on the test case specifications, CAD modeling methods, versions of CAD software, and comparison methodologies. PMI representation and presentation are evaluated by many verification characteristics and validation issues. The results may identify issues relevant to your use cases for downstream automated-consumption of PMI representation or human-interpretation of PMI presentation.

To test how well your CAD system implements STEP AP242 PMI, open one of the CAD models, export an AP242 file with PMI and process it with the STEP File Analyzer and Viewer. The STEP File Analyzer and Viewer results will indicate how well the AP242 PMI matches the expected PMI in the test case definition. Differences might be due to how some PMI was modeled in the CAD system or how the PMI was exported to the STEP file.

Other Data and Testing

Disclaimers

NIST Disclaimer

The test cases are not intended to represent best practice in how to apply GD&T to a part. Simpler GD&T strategies could have been used. The test cases are intended to exercise valid presentations of GD&T defined in the ASME Y14 standards.

The test cases, CAD models, and STEP files can be used without any restrictions. Their use in other software or hardware products does not imply a recommendation or endorsement of those products by NIST.

The verification and validation testing results related to the test case PMI were generated based on older versions of the CAD systems. Issues identified for the semantic and graphic representation of PMI in each CAD system may have been (and hopefully have been) resolved since the original testing took place.

We would appreciate acknowledgement if any of the test cases, CAD models, STEP files, or screenshots of the models are used, however, the use of the NIST logo seen at the top of this page is not allowed in promotional materials.

Created August 29, 2016, Updated June 19, 2024