Overview
The second edition of AP242, published in April 2020, 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.
This has since been replaced by a third edition in 2022.
Programming Notes
The second edition of AP242 contains many new entities and some adjustments to entity attributes and select types. STEP has a firm rule that changes should not break existing data files, but some programming adjustments may be needed.
One common change adjusts an attribute from an entity to a select of several different kinds of entities. This often happens as a model is tested in new situations. The Part 21 file looks the same in both cases, but programming access is slightly different.
This kind of change was made
to representation_relationship,
which is found in most geometry. The rep_1
and rep_2 fields now refer to a select type rather than
directly to representation. The following functions in the
STEP AP Helper Library will simplify
adjusting your code:
stix_get_reprel_1(rel) --> replaces rel->rep_1() stix_get_reprel_2(rel) --> replaces rel->rep_2() stix_put_reprel_1(rel,rep) --> replaces rel->rep_1(rep) stix_put_reprel_2(rel,rep) --> replaces rel->rep_2(rep)
A number of recommended practice documents are available on the CAx-IF site for things introduced in AP242.
New Entity Definitions
The 2020 second edition of AP242 contains about 400 new EXPRESS entities beyond the 2014 first edition:
a3m_equivalence_accuracy_association a3m_equivalence_assessment_by_logical_test a3m_equivalence_assessment_by_numerical_test a3m_equivalence_criteria_representation a3m_equivalence_criterion a3m_equivalence_criterion_for_assembly a3m_equivalence_criterion_for_shape a3m_equivalence_criterion_of_assembly_data_structure a3m_equivalence_criterion_of_component_property_difference a3m_equivalence_criterion_of_detailed_assembly_data_content a3m_equivalence_criterion_of_detailed_shape_data_content a3m_equivalence_criterion_of_representative_assembly_property_value a3m_equivalence_criterion_of_representative_shape_property_value a3m_equivalence_criterion_of_shape_data_structure a3m_equivalence_criterion_report_item_with_measured_value a3m_equivalence_criterion_with_specified_elements a3m_equivalence_inspection_instance_report_item a3m_equivalence_inspection_requirement_with_values a3m_equivalence_inspection_result_representation a3m_equivalence_inspection_result_representation_for_assembly a3m_equivalence_inspection_result_representation_for_shape a3m_equivalence_summary_report_request_with_representative_value a3m_inspected_model_and_inspection_result_relationship a3ma_assembly_and_shape_criteria_relationship a3ma_equivalence_criterion_assessment_threshold_relationship a3ma_equivalence_inspection_result a3ma_length_measure_and_context_dependent_measure_pair a3ms_equivalence_criterion_with_specified_elements a3ms_equivalence_inspection_result action_actual action_directive_relationship action_happening action_resource_relationship additive_manufacturing_build_plate_relationship additive_manufacturing_setup additive_manufacturing_setup_relationship additive_manufacturing_setup_workpiece_relationship additive_manufacturing_support_structure_geometry_relationship aggregate_id_attribute alternative_solution_relationship analysis_assignment analysis_item analysis_model analysis_representation_context annotation_placeholder_occurrence annotation_point_occurrence ap242_assignment_object_relationship applied_classification_assignment_relationship applied_description_text_assignment applied_description_text_assignment_relationship applied_directed_action_assignment applied_external_identification_assignment_relationship applied_location_assignment applied_location_representation_assignment applied_organization_type_assignment applied_state_observed_assignment applied_state_type_assignment ascribable_state ascribable_state_relationship assembly_shape_constraint assembly_shape_constraint_item_relationship assembly_shape_joint assembly_shape_joint_item_relationship assigned_analysis assignment_object_relationship attachment_slot_as_planned attachment_slot_as_realized attachment_slot_design attachment_slot_design_to_planned attachment_slot_design_to_realized attachment_slot_on_product attachment_slot_planned_to_realized b_spline_volume b_spline_volume_with_knots banded_matrix bezier_volume block_volume bound_variable_semantics cartesian_11 characterized_location_object characterized_object_relationship characterized_product_concept_feature characterized_product_concept_feature_category circular_involute classification_assignment_relationship clothoid collection collection_assignment collection_membership collection_relationship collection_version collection_version_relationship collection_version_sequence_relationship collection_view_definition condition conditional_effectivity connected_edge_with_length_set_representation connected_volume_set connected_volume_sub_set connectivity_definition connectivity_definition_item_relationship constituent_shape_aspect contact_feature contact_feature_definition contact_feature_definition_fit_relationship contact_feature_fit_relationship containing_message counterbore_hole_definition counterbore_hole_occurrence counterbore_hole_occurrence_in_assembly counterdrill_hole_definition counterdrill_hole_occurrence counterdrill_hole_occurrence_in_assembly countersink_hole_definition countersink_hole_occurrence countersink_hole_occurrence_in_assembly criterion_report_item_with_number_of_instances criterion_report_item_with_value cross_sectional_alternative_shape_element cross_sectional_group_shape_element cross_sectional_group_shape_element_with_lacing cross_sectional_group_shape_element_with_tubular_cover cross_sectional_occurrence_shape_element cross_sectional_part_shape_element cubic_bezier_tessellated_edge cubic_bezier_triangulated_face cubic_tessellated_connecting_edge curve_11 cylindrical_11 cylindrical_point cylindrical_volume data_equivalence_assessment_specification data_equivalence_criteria_representation data_equivalence_criterion data_equivalence_definition data_equivalence_definition_relationship data_equivalence_definition_representation_relationship data_equivalence_inspected_element_pair data_equivalence_inspection_criterion_report data_equivalence_inspection_criterion_report_item data_equivalence_inspection_instance_report data_equivalence_inspection_instance_report_item data_equivalence_inspection_report data_equivalence_inspection_requirement data_equivalence_inspection_result data_equivalence_inspection_result_representation data_equivalence_inspection_result_with_judgement data_equivalence_report_request default_model_geometric_view definitional_product_definition_usage dependent_variable_definition description_text description_text_assignment description_text_assignment_relationship detailed_equivalence_report_request detailed_equivalence_report_request_with_number_of_instances different_angle_of_assembly_constraint different_assembly_centroid different_assembly_centroid_using_notional_solid different_assembly_constraint_type different_assembly_volume different_bounding_box different_centroid different_component_identification_via_multi_level_reference different_component_shape different_component_type different_curve_length different_length_of_assembly_constraint different_number_of_closed_shell different_number_of_components different_number_of_geometric_elements different_number_of_geometric_elements_wireframe_model different_number_of_topological_elements different_number_of_topological_elements_wireframe_model different_placement_of_component different_surface_area different_surface_normal different_volume directed_action_assignment directed_tolerance_zone draped_orientation_angle draughting_model_item_association_with_placeholder draughting_specification_reference dupin_cyclide_surface eccentric_conical_volume edge_with_length ellipsoid_volume envelope envelope_relationship equivalence_instance_report_item_with_notable_instances equivalence_notable_instance evidence explicit_composite_hole explicit_round_hole external_identification_assignment_relationship final_solution fixed_reference_swept_surface free_variable_semantics generic_property_relationship geometric_tolerance_auxiliary_classification gps_filter gps_filtration_specification harness_node harness_segment hexahedron_volume hierarchical_interface_connection identification_assignment_relationship idrm_classification_assignment in_zone interface_component interface_connection interface_connector_as_planned interface_connector_as_realized interface_connector_definition interface_connector_design interface_connector_design_to_planned interface_connector_design_to_realized interface_connector_occurrence interface_connector_planned_to_realized interface_connector_version interface_definition_connection interface_definition_for interface_specification_definition interface_specification_version laid_orientation_angle listed_complex_number_data listed_integer_data listed_logical_data listed_real_data listed_string_data local_b_spline locally_refined_spline_curve locally_refined_spline_surface locally_refined_spline_volume location location_assignment location_relationship location_representation_assignment location_representation_role location_role machining_process_executable mathematical_description maths_boolean_variable maths_integer_variable maths_real_variable maths_string_variable maths_value_precision_qualifier mating_material mating_material_items mechanical_design_requirement_item_association message_contents_assignment message_contents_group message_relationship mismatch_of_arcwise_connected_curves mismatch_of_arcwise_connected_surfaces mismatch_of_arcwise_connected_surfaces_boundary mismatch_of_component mismatch_of_edges mismatch_of_faces mismatch_of_point_cloud_and_related_geometry mismatch_of_points mismatch_of_underlying_edge_geometry mismatch_of_underlying_face_geometry missing_assembly_constraint missing_component missing_edge missing_face model_geometric_view open_path organization_type organization_type_assignment organization_type_role oriented_tolerance_zone physical_component_interface_terminal ply_angle_representation ply_orientation_angle pmi_requirement_item_association point_array point_cloud_dataset point_cloud_dataset_with_colours point_cloud_dataset_with_intensities point_cloud_dataset_with_normals point_cloud_superdataset point_in_volume polar_11 polar_point positive_length_measure_with_unit positive_plane_angle_measure_with_unit procedural_solid_representation_sequence product_data_and_data_equivalence_relationship product_definition_formation_resource product_definition_occurrence product_definition_occurrence_reference product_definition_occurrence_reference_with_local_representation product_definition_relationship_relationship product_definition_specified_occurrence product_definition_usage_relationship product_group product_group_attribute_assignment product_group_attribute_set product_group_attributes product_group_context product_group_membership product_group_membership_rules product_group_purpose product_group_relationship product_group_rule product_group_rule_assignment product_group_rules product_in_attachment_slot product_resource pyramid_volume quasi_uniform_volume rational_b_spline_volume rational_locally_refined_spline_curve rational_locally_refined_spline_surface rational_locally_refined_spline_volume regular_table_function reinforcement_orientation_basis representation_context_reference representation_reference same_as_external_item_assignment scan_3d_model scan_data_shape_representation scanned_data_item scanner_basic_properties scanner_property seam_edge shape_aspect_occurrence shape_feature_definition_element_relationship shape_feature_definition_fit_relationship shape_feature_definition_relationship shape_feature_fit_relationship shape_representation_reference simplified_counterbore_hole_definition simplified_counterdrill_hole_definition simplified_countersink_hole_definition simplified_spotface_hole_definition single_texture_style_tessellation_specification spherical_point spherical_volume spotface_definition spotface_hole_definition spotface_occurrence spotface_occurrence_in_assembly standard_table_function state_definition_to_state_assignment_relationship state_observed state_observed_assignment state_observed_relationship state_observed_role state_predicted state_type state_type_assignment state_type_relationship state_type_role statechar_applied_object statechar_object statechar_relationship_object statechar_type_applied_object statechar_type_object statechar_type_relationship_object strict_triangular_matrix structured_message styled_tessellated_item_with_colours summary_report_request_with_number_of_instances surface_curve_swept_surface symmetric_banded_matrix symmetric_matrix system_breakdown_context system_element_usage terminal_feature terminal_location_group tessellated_shape_representation_with_accuracy_parameters tetrahedron_volume texture_style_specification texture_style_tessellation_specification tolerance_zone_with_datum toroidal_volume transport_feature triangular_matrix triangulated_point_cloud_dataset twisted_cross_sectional_group_shape_element uniform_volume user_defined_11 validation validation_software_identification verification verification_relationship vertex_on_edge volume_with_faces volume_with_parametric_boundary volume_with_shell wedge_volume zone_breakdown_context zone_element_usage