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Testing Implementations of Geometric Dimensioning and Tolerancing in CAD Software
Robert R Lipman1, James J Filliben1
1National Institute of Standards and Technology (NIST).
Computer-Aided Design and Applications
|October 12, 2020
Summary
This study introduces a new system from NIST to rigorously test how computer-aided design (CAD) software implements geometric and dimensional tolerances (GD&T). The findings reveal errors in CAD systems, providing a basis for future standards in GD&T application.
Area of Science:
- Engineering
- Computer Science
- Metrology
Background:
- Geometric and dimensional tolerances (GD&T) are crucial for part functionality and manufacturing.
- Current understanding of GD&T implementation in CAD software is limited, lacking public-domain testing.
- Existing CAD software testing is typically vendor-internal or user-based, not rigorously standardized.
Purpose of the Study:
- To develop and implement a system for testing GD&T capabilities in CAD software.
- To identify and analyze errors in the semantic and graphical representation of GD&T within major CAD systems.
- To establish a foundation for future standardized testing and evaluation of GD&T implementations.
Main Methods:
- Modeled representative part geometry with GD&T applied in four major CAD systems.
- Developed a testing system to evaluate GD&T implementations.
- Collected and analyzed errors related to semantic and graphical presentation of GD&T.
Main Results:
- Identified and documented errors in GD&T semantic and graphical representations across tested CAD systems.
- Demonstrated the performance of CAD system GD&T implementations through rigorous testing.
- Provided empirical data on the effectiveness and accuracy of GD&T application in CAD.
Conclusions:
- The developed testing system effectively evaluates GD&T implementations in CAD software.
- Significant errors exist in current CAD software's handling of GD&T, impacting manufacturing and inspection.
- The results serve as a crucial basis for improving GD&T standards and testing methodologies in CAD.
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