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I++ DME (Dimensional Measurement Equipment)


The I++ (Inspection plus-plus) group is a loose consortium of European automobile manufacturers: Daimler, Audi, BMW, Opel, Volkswagen, Porsche, and Volvo. I++ DME is one of two current efforts pursued by the I++ group. I++ DME has demonstrable support from U.S. users and vendors of coordinate measuring machines (CMM) and CMM measurement plan execution software.

The scope of this industry-led effort is on the exchange of dimensional measuring equipment commands and results between measurement execution software and a CMM.

NIST's role is to 1) contribute to the writing of I++ DME, 2) generate conformance tests, 3) design and conduct public interoperability tests, and 4) act as standards consultants and leaders in industry standards organizations through summit meetings and other initiatives.


Industry Impact

  • Adoption of  I++ DME by a majority of vendors worldwide with compliant apps has been largely achieved due to
  • Strong end user and CMM vendor support through groups such as I++ group, NIST, Dimensional Metrology Standards Consortium, International Association of CMM Manufacturers, and the Automotive Industry Action Group
  • NIST I++ DME compliance test suite, allowing quick and compliant implementation development
  • Five successful, non-trivial public interoperability tests in Europe and the U.S. initiated and lead by NIST, with willing participation for CMM software and hardware vendors worldwide  
  • Implementers meetings and public wiki site for implementer/spec-writer interaction
  • Detailed analysis of the I++ DME specification by NIST and others early in the life of I++ DME


  • I++ DME is NOT a standard, but rather a tightly controlled specification by a small group of CMM vendors and CMM end users
  • Legal problems and concerns expressed at the NIST-organized Metrology Interoperability Summit Meeting 2006, were later addressed satisfactorily by the I++ Group
  • I++ DME is for fixed CMMs only, and it remains to extend I++ DME to a variety of other types of CMMs, including CMMs with non-contact optical sensors, laser trackers, and articulated arm CMMs
  • The I++ group has a vision for the entire standards infrastructure (includes I++ DMS)
  • Commercial-Off-The-Shelf offerings of I++DME-compliant products are rare, even though the capability exists in alpha and beta software versions

To-Do List

  • Harmonize America, Europe, Asia visions about the precise information content on the DME interface
  • Encourage I++ DME standardization
  • Encourage Commercial-Off-The-Shelf offerings of I++DME-compliant products
  • Update NIST compliance test suite
  • Extend I++ DME to portable metrology devices
Created March 25, 2009, Updated July 8, 2023