<html><head><meta http-equiv="content-type" content="text/html; charset=us-ascii"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Dear Martin,<div>Here is a short summary of the progress on the AP 242 information model UUID effort.</div><div>We anticipate a ballot on this during the fall.</div><div><br></div><div>See associated Jira issue</div><div><a href="https://sd.iso.org/jira-pilot/browse/TCSC410303-14">https://sd.iso.org/jira-pilot/browse/TCSC410303-14</a></div><div><br></div><div>Best Regards,</div><div>Tom Thurman</div><div><br></div><div><p style="margin: 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">Status report:</p><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">Good progress has been made on basic application of UUID to a single record in a STEP data set.</p><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">We are ready to request a module part number from ISO, as we need to deliver a model for AP 242e4.</p><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">For MCAD, we are expecting that CAD software implementors attach a UUID attribute to a node in the source model tree. This aligns with the Hybrid model effort led by <a href="https://sd.iso.org/jira-pilot/secure/ViewProfile.jspa?name=benurick%40nvariate.com" class="user-hover" rel="benurick@nvariate.com" style="color: rgb(0, 82, 204); text-decoration: var(--aui-link-decoration); cursor: pointer;">Ben Urick</a>. For the single target record use case, we are proposing directly specifying either a identification_item SELECT or a id_attribute_select SELECT. (It is noted that the consequence of this decision is that we will need to deal with the mapping specification issue of multiple assertions involving identfication_item.)</p><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;"> </p><hr style="caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;"><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">We are currently investigating how to address aggregate use cases:</p><ul style="margin: 10px 0px 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;"><li>connected instance graph where the pre-processor can infer association<ul style="margin: 0px;"><li>e.g., using a shape_aspect as a pseudo-root node with multiple records referencing it as defined by an entry in a mapping specification.</li><li>Using a property_definition as a pseudo-root node with a sequence of records associated to it as defined in a mapping specification<ul style="margin: 0px;"><li>The model does not formally specify a mapping specification but is a possibility to investigate in the future is the approach of specifying an ARM AO as a target. That would require a formal mechanism for referencing an AO which does not currently exist in STEP from an AIM data set. </li></ul></li><li>Where there is a CAX-IF instance data requirement specified that can be reference by e.g., recommended practice name, version, clause.</li></ul></li><li>Dis-connected instance graph where an external pre-processor specifies an aggregate for a business purpose based on an exchange agreement.</li></ul><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">It is noted that representation is a strong containerization concept in STEP.</p><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">It is noted that item_identified_representation_usage (IIRU) provides the ability to subset a representation.</p><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">Current trade studies include:</p><ul style="margin: 10px 0px 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;"><li>structural options for aggregate use case (there is a uniqueness constraint that only one instance of UUID can reference an item of product data). Each of the following options addresses the requirement for a shape_aspect as an aggregator node in the STEP model while permitting supporting the single item use case.<ul style="margin: 0px;"><li>Define the UUID <b>identified items</b> as a recursive structure of UUIDs that specify a LIST of records at the tail 'call'</li><li>Define the UUID <b>identified items</b> as a LIST OF LIST of records</li></ul></li><li>Integrate a merkle tree (see wikipedia and the THEX exchange format) with the UUID attribute structure. (The leaf nodes of a merkle tree point to a data record). It is anticipated there will be multiple merkle trees in an exchange data set.<ul style="margin: 0px;"><li><ul style="margin: 0px;"><li>A merkle tree model that appears to be compliant to the THEX exchange model has been created</li><li>Naive model integration with the UUID model increases instance count because the UUID is an instance and the merkle tree node is an instance</li><li>Fully integrated model has complex SUBTYPE graph (to cover corner cases)</li><li>Merkle trees can be costly to create when data sets are large.</li><li>Hash functions are agreed to be user defined and reference to the hash function is exchanged.</li><li>The UUID function is called after the hash is created.</li><li>Cryptographic hash functions can be applied that may alter the cost-benefit ratio but encrypting the STEP data is not currently in scope of this issue.</li></ul></li></ul></li></ul><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">Historically, the STEP pre-processors have strongly aligned with the principle that only data that exists in the internal CAD model shall be converted to STEP product data. Adding the single UUID to a STEP record is non-controversial and sought after by multiple parties and is moving forward. Neither of the two aggregate options are part of current practice.</p><p style="margin: 10px 0px 0px; padding: 0px; caret-color: rgb(23, 43, 77); color: rgb(23, 43, 77); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;">Comments by parties identified as watchers on this issue are solicited. Feel free to send direct email to <a href="https://sd.iso.org/jira-pilot/secure/ViewProfile.jspa?name=thomas.r.thurman%40imonmail.com" class="user-hover" rel="thomas.r.thurman@imonmail.com" style="color: rgb(0, 82, 204); text-decoration: var(--aui-link-decoration); cursor: pointer;">Thurman Tom Mr</a> or attach comments to the issue.</p><div><br><blockquote type="cite"><div>On Jun 21, 2023, at 6:21 AM, Martin Hardwick <hardwick@steptools.com> wrote:</div><br class="Apple-interchange-newline"><div><div>hardwick@steptools.com has invited you to UUID Management across distributed systems<br><br></div></div></blockquote></div></div></body></html>