Dimensional Measuring Interface
Standard
Standard Improvement Request
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SIR No. 97-50 DMIS Release 3.0 SIR Type Enhancement Severity Interpretation Request Status Resolved Date Submitted August 12 1997 Date Validated August 12 1997 Date In Process Date Referred Date Vote Pending Date Closed April 1 1998 Action Clarifications Submitted By Thomas Kramer NIST Room B-124, Bldg. 220 Gaithersburg MD 20899 USA Phone: (301)975-3518 Fax: (301)990-9688 kramer@cme.nist.gov |
Problem Topic
Sect.3.13: Clarification on CS of output data
Problem Description
Page 27, section 3.13
It is not clear whether output data should be expressed in the current coordinate system, the coordinate system in effect when the the feature was defined, or the coordinate system in effect when the feature was measured.
References
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Related SIRs
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Suggested Resolution
Decide in what coordinate system output should be expressed and include
this information in section 3.13 and in the section that describes the
OUTPUT command.
Support Documentation
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Resolution
Warning!!
The following statement is only a resolution to a Standard Improvement Request (SIR) and is NOT part of the current DMIS standard, nor is it guaranteed to become part of the next revision of the DMIS standard even if voted and accepted by the DMIS National Standards Committee. This resolution is tentative because it may not be incorporated into the next version of the standard, it could be changed prior to the next release, or it could be changed as the result of the "public review and comment" period required for the next version of the standard. If you choose to use this tentative resolution, you do so at your own risk since at this time it is not part of the DMIS standard.
The following resolution was accepted by the DNSC for this SIR:
Feature nominal coordinates shall retain their original values during any subsequent coordinate system transformations, with nominal values unchanged throughout the execution of the system. Therefore, a nominal coordinate is not directly associated with or expressed in any coordinate system; however, the nominal coordinate shall be utilized as a location relative to the origin of the current coordinate system at the time it is applied. Conversely, feature actual coordinates always reference the same absolute location within 3D space, but are transformed (when used) into the current coordinate system.
A location for this clarification was not specified, but a likely candidate is to add it to the end of page 111. Another candidate would be somewhere in section 3. This needs to be determined at the next meeting.
An enhancement SIR was also proposed to add a new major word, such as NOMUPD/[ON,OFF], which would control a modal setting within the DME software. When off, the DME should operate in the mode as specified in the clarification above. However, when the nominal is first applied (as in MEAS), the current part coordinate system would be associated with the nominal feature. then, during subsequent uses of the feature nominal, if the nominal update setting is on, its coordinate would be transformed into the coordinate system that is current at the time of use.
This modal nominal update setting should apply only within a carriage common section
This needs to be formally proposed as an SIR.
Attachments
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Notes
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