Reference dimension

<h2 id="notation">Notation</h2>
<p>In Computer-Aided Design (<a href="/facts/Computer-aided_design/5gSXrmmN">CAD</a>) it's commonly used to denote dimensions.
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<h3>REF</h3>
<p>Prior to use of modern CAD software, reference dimensions were traditionally indicated on a drawing by the abbreviation "REF" written adjacent to the dimension (typically to the right or underneath the dimension).
</p><p>However, standard ASME Y14.5 has changed the way references are marked, and the abbreviation "REF" has been replaced with the use of parentheses () around the dimension. As an example, a distance of 1500 millimeters might be denoted by (1500 mm) instead of 1500 mm REF.
</p><p>This implementation has followed in modern <a href="/facts/CAD_software/5gSXrmmN">CAD software</a> that makes use of parentheses as the default denotation method whenever reference dimensions are "automatically" created by the software. The method for identifying a reference dimension (or reference data) on drawings is to enclose the dimension (or data) within parentheses.
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Engineering_drawing_abbreviations_and_symbols/BU2GG66H">Engineering drawing abbreviations and symbols</a>
<ul><li><a href="/facts/Geometric_dimensioning_and_tolerancing/xlfqadu6">Geometric dimensioning and tolerancing</a></li></ul></li>
<li><a href="/facts/ASME_Y14.5/La6WGxEp">ASME Y14.5</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://www.asme.org/products/codes-standards/y145-2009-dimensioning-and-tolerancing">Y14.5 Dimensioning and Tolerancing</a>, 2018, <a href="/facts/American_Society_of_Mechanical_Engineers/gpM3UR6G">ASME</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Reference Dimensions - 2017 - SOLIDWORKS Help". help.solidworks.com. Retrieved 2022-01-20. <a href="https://help.solidworks.com/2017/english/SolidWorks/sldworks/c_Reference_Dimensions.htm" target="_blank">https://help.solidworks.com/2017/english/SolidWorks/sldworks/c_Reference_Dimensions.htm</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Sheaffer, M. K.; Thomas, G. R.; Dann, R. K.; Russell, E. W. (May 1998), Engineering Drawings for 10 CFR Part 71 Package Approvals (PDF), pp. 11–12, retrieved 2019-02-15. <a href="https://www.orau.org/ptp/pdf/5502.pdf" target="_blank">https://www.orau.org/ptp/pdf/5502.pdf</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Sheaffer, M. K.; Thomas, G. R.; Dann, R. K.; Russell, E. W. (May 1998), Engineering Drawings for 10 CFR Part 71 Package Approvals (PDF), pp. 11–12, retrieved 2019-02-15. <a href="https://www.orau.org/ptp/pdf/5502.pdf" target="_blank">https://www.orau.org/ptp/pdf/5502.pdf</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
</ol>

Reference dimension open-in-new

Reference dimension