The third edition of AP242, published in December 2022, a number of new definitions for presentation, features, and model associativity.

This builds on the second edition, which introduced about 400 new definitions for semantic tolerances, additive setup, improved tesselated models and point cloud data, new types of hole features, annotated 3D model equivalence (A3M), and electrical wire harness.

The second edition built on the first edition, which added 533 definitions for kinematics, assembly constraints, and PMI, beyond what AP214 and AP203e2 could handle.

Programming Notes

The AP242 schema name has not changed between editions, so the StplibSchemaType stplib_schema_ap242 enum is still used to identify all AP242 files.

RoseDesign * d;

stplib_put_schema (d, stplib_schema_ap242);

switch (stplib_get_schema(d)) {
case stplib_schema_ap242:
    // ap242 E1/E2/E3

When writing new files as AP242, we append the second edition ASN/1 version identifier to the schema name. You can examine the original schema name string found in the STEP Part 21 file with stplib_get_schema_name() or change it with stplib_put_schema_name()

 { 1 0 10303 442 1 1 4 }   ASN/1 for first edition
 { 1 0 10303 442 3 1 4 }   ASN/1 for second edition
 { 1 0 10303 442 4 1 4 }   ASN/1 for third edition

The third edition of AP242 contains many entities but no known adjustments to entity attributes, so no programming adjustments to existing code should be needed.

New Entity Definitions

The 2022 third edition of AP242 adds the new entities listed below:

The values of several enums were reordered:

And finally, the third edition also retires several definitions that were added in the second edition, but never implemented.