CAD Formats

Introduction

Harvard Library collections include 2D and 3D objects representing art, architectural, archaeological, museum, engineering and other objects. This digital material will be preserved in the Library’s preservation and access repository - the Digital Repository Service (DRS).

As a first step towards providing support for this material in the DRS, the Library contracted initially with Drexel University and later with Isaac Simmons to perform the foundational research and development. The goals of the analysis were:

  • Recommended 2D and 3D formats to accept and prefer for the DRS
  • Recommended technical metadata schema(s) to use for files in 2D and/or 3D formats
  • DRS content models for 2D and 3D objects
  • Recommendations for enhancing Harvard Library’s FITS tool to better support 2D and 3D objects

The driving principles of this work were to:

  • Provide interoperability with the existing metadata schemas and workflows of the DRS
  • Provide sufficient metadata for long-term preservation of 2D and 3D objects
  • Adhere to existing standards where possible
  • Propose simpler models over more complex ones where possible

The deliverables from this analysis are included on this page.

The Drexel University team included:

  • Jane Greenberg
  • Isaac Simmons, Research Engineer
  • Adrian Ogletree, Research Program Manager, Metadata Research Center
  • Colleen Kavanaugh, Program Administrator

Format Analysis

DocumentDescriptionAuthors
Format matrix (2D CAD formats)This spreadsheet compares 2D CAD formats according to preservation criteria (shown in the first column). 
The cells are shaded to visually represent the value for the format (green is good, yellow is neutral, red is bad) 
Drexel University
Format matrix (3D CAD formats)This spreadsheet compares 3D CAD formats according to preservation criteria (shown in the first column). 
The cells are shaded to visually represent the value for the format (green is good, yellow is neutral, red is bad) 
Drexel University

Formatprofile-DWG.docx

FormatProfile-DXF.docx

Formatprofile-PDFA.docx

Formatprofile-PDFE.docx

Formatprofile-STEP.docx

Formatprofile-X3D.docx

These documents are brief profiles of the CAD formats that were under consideration for acceptance in the DRS.
Along with descriptive information about the format, they include a summary of risks and potential strategies for mitigating the risks.
Drexel University
3D in PDFsThis document describes the 3D formats within different versions of PDF.Andrea Goethals

Metadata Analysis

DocumentDescriptionAuthors
Metadata recommendationsThis document contains recommendations for the metadata elements to capture and a glossary of some of CAD terms.Drexel University
CAD-MD and DOC-MD recommendationsThis document defines a new schema (CADMD) to document the technical metadata for CAD files, changes to DocMD to support CADMD,
a sample instance of CADMD, and related notes.
Isaac Simmons

Tool Analysis and Testing

DocumentDescriptionAuthors
Metadata extraction optionsThis spreadsheet compares tools that could extract metadata for files in DWG and/or DXF formats.Isaac Simmons
3rd party software surveyThis document lists viewers and converters for CAD formats.Isaac Simmons

Other Resources

DocumentDescriptionAuthors
CADTool

This is a tool to perform identification, validation and metadata extraction on a limited set of CAD file formats. It is designed to work with FITS.
This tool will be integrated with FITS by Harvard Library. 

Isaac Simmons

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