Download Free CAD Models, STEP Files, and Test Results

Download

1. Native CAD Models for the four type of test cases described below.
2. FTC Definitions and CTC Definitions.  The definition files contain PDFs of each test case drawing, STEP AP203 files of only the test case geometry, and an explanation of the GD&T.  These files can be used to create your own CAD models of the test cases.  Browse the PMI annotations in the test cases.
3. Sample STEP Files.  STEP AP242 and AP203 files for each FTC and CTC, many with graphical and semantic PMI.

Types of Test Cases

The FTC and CTC were part of the original testing project described in the link to the left for the MBE PMI Validation and Conformance Testing Project.  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 MTC are modified versions of some of the FTC where the geometry and PMI is different.

Fully-Toleranced Test Cases (FTC)

• Download the FTC Definitions including sample STEP AP203 files of model geometry only and explanations of all PMI
• FTC 07, 08, 09, and 10 fit together in an assembly

Combined Test Cases (CTC)

• Download the CTC Definitions including sample STEP AP203 files of model geometry only and explanations of all PMI
• The CTC are not intended to be fully toleranced.  CTC 02 and 04 fit together in an assembly

Simplified Test Cases (STC)

Some of the FTC 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 STC can be downloaded as CAD models generated in Dassault Systèmes CATIA, Siemens NX, and Autodesk Inventor.

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.
 

• Download the SolidWorks and Siemens NX models
• 3D model of the assembly generated by the STEP File Analyzer and Viewer
• Visualizing Model-Based Product Definitions in Augmented Reality

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.

• Testing Implementations of Geometric Dimensioning and Tolerancing in CAD Software

• Guide to the CAD Models and Verification Testing Results
• Browse the Verification Testing Results for annotations
• Measuring the PMI Modeling Capability in CAD Systems: Report 1 - Combined Test Case Verification (Slides) - compares test case specifications for PMI to CAD models
• Measuring the PMI Modeling Capability in CAD Systems: Report 2 - Combined Test Case Validation (Slides) - compares CAD models to STEP, JT, and 3D PDF files
• Measuring the PMI Modeling Capability in CAD Systems: Report 3 - Fully-Toleranced Test Case Verification (Slides) - compares test case specification for PMI to CAD models

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

• Download the CAD files from the Design to Manufacturing and Inspection (D2MI) project.
• The MBE Demonstrator Reference Model contains CAD models and STEP files for an airplane.
• STEP AP242 Benchmark Testing is a European project that tested AP242 with a larger set of models, a different set of CAD software, and a different test methodology and criteria.

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.