Application module: Contextual shape positioning ISO/TS 10303-1027:2021(E)
© ISO

Cover page
Table of contents
Copyright
Foreword
Introduction
1 Scope
2 Normative references
3 Terms, definitions and abbreviated terms
    3.1 Terms and definitions
    3.2 Abbreviated terms

4 Information requirements
   4.1 Required AM ARMs
   4.2 ARM type definitions
   4.3 ARM entity definitions
5 Module interpreted model
   5.1 Mapping specification
   5.2 MIM EXPRESS short listing

A MIM short names
B Information object registration
C ARM EXPRESS-G   EXPRESS-G
D MIM EXPRESS-G   EXPRESS-G
E Computer interpretable listings
F Change history
Bibliography
Index

4 Information requirements

This clause specifies the information requirements for the Contextual shape positioning application module. The information requirements are specified as the Application Reference Model (ARM) of this application module.

NOTE 1  A graphical representation of the information requirements is given in Annex C.

NOTE 2  The mapping specification is specified in 5.1. It shows how the information requirements are met by using common resources and constructs defined or imported in the MIM schema of this application module.

This clause defines the information requirements to which implementations shall conform using the EXPRESS language as defined in ISO 10303-11. The following begins the Contextual_shape_positioning_arm schema and identifies the necessary external references.

WARNING:

For users and implementers of this standard please note that the Geometric Modeling methodology employed herein is unique and therefore limited solely to this usage, and only this usage, due to its uncommon characteristics.

ISO 10303 defines a critical associativity between geometry and topology that is carefully defined and constrained to provide the reproducibility, reliability, robustness, and completeness necessary in industrial product modeling based on vetted mathematical foundations (i.e., see Section "Geometric model schema" of ISO 10303-42). ISO 10303 employs a methodology of building hybrid product structure (non-geometric) and (geometric) assembly model structures that associate a rigid body tensor transform to place geometric models of the parts in the geometric model of the assembly. Those hybrid structures decompose the hybrid structure, the relationship to the transform, and the transform into separate EXPRESS constructs, however they are designed and integrated to function as a single model.

The reference in a hybrid assembly model (i.e., Geometric_model_relationship defined in AM 1403) from a context_dependent_shape_representation to a combined subtype of shape_representation_relationship and representation_relationship_with_transformation to create associations between Geometric models deviates from the above approach in ISO 10303. It should therefore be strictly limited to the use of Wiring harness assembly design, not utilized outside of that scope, with care taken by users and implementers to understand its particular construction, limitations, and conditions.

EXPRESS specification:

*)
SCHEMA Contextual_shape_positioning_arm;
(*

4.1 Required AM ARMs

The following EXPRESS interface statements specify the elements imported from the ARMs of other application modules.

EXPRESS specification:

*)
USE FROM Geometric_model_relationship_arm;    --  ISO/TS 10303-1403

USE FROM Shape_property_assignment_arm;    --  ISO/TS 10303-1032
(*

NOTE 1   The schemas referenced above are specified in the following part of ISO 10303:

Geometric_model_relationship_arm ISO/TS 10303-1403
Shape_property_assignment_arm ISO/TS 10303-1032

NOTE 2   See Annex C, Figures C.1and C.2 for a graphical representation of this schema.

4.2 ARM type definitions

This subclause specifies the ARM types for this application module. The ARM types and definitions are specified below.

4.2.1 product_context_select   EXPRESS-G

The product_context_select type allows for the designation of the data types View_definition_relationship and Product_occurrence_definition_relationship.

Items of the product_context_select select can be used as product_context for an Contextual_shape_representation.

EXPRESS specification:

*)
TYPE product_context_select = SELECT
   (View_definition_relationship,
    Product_occurrence_definition_relationship);
END_TYPE;
(*

4.2.2 template_instance   EXPRESS-G

The template_instance type allows for the designation of the data types Geometric_placement_operation and Geometric_model_relationship_with_transformation.

EXPRESS specification:

*)
TYPE template_instance = SELECT
   (Geometric_placement_operation,
    Geometric_model_relationship_with_transformation);
END_TYPE;
(*

4.3 ARM entity definitions

This subclause specifies the ARM entities for this module. Each ARM application entity is an atomic element that embodies a unique application concept and contains attributes specifying the data elements of the entity. The ARM entities and definitions are specified below.

4.3.1 Axis_placement_mapping   EXPRESS-GMapping table

An Axis_placement_mapping is a geometric transformation that is defined by a source and a target Representation_item that are mapped onto each other. The default kind of source and target types defined in this module are Axis_placements only. Other application modules may define further subtypes of Representation_item that can be used to define the mapping.

NOTE    By construction, the determinant of the transformation matrix equals one.

EXPRESS specification:

*)
ENTITY Axis_placement_mapping;
  source : Axis_placement;
  target : Axis_placement;
END_ENTITY;
(*

Attribute definitions:

source: the Axis_placement that plays the role of source in the transformation.

target: the Axis_placement that plays the role of target in the transformation.

4.3.2 Contextual_shape_representation   EXPRESS-GMapping table

A Contextual_shape_representation is an association of a Geometric_model_relationship to a product structure relationship. The association between the Geometric_model_relationship and the product structure relationship is established in such a way that the related view of the product structure corresponds to the rep_1 attribute of the Geometric_model_relationship and the relating view of the product structure corresponds to the rep_2 attribute of the Geometric_model_relationship. The product structure relationship provided by a product_context_select is either a View_definition_relationship or a Product_occurrence_definition_relationship. The Geometric_model_relationship may be a Geometric_model_relationship_with_transformation that reflects the transformation between the Geometric_models of the corresponding product structure; or the related and relating Geometric_models of the Geometric_model_relationship share the same Geometric_coordinate_space.

NOTE    To provide consistency, the referenced Geometric_models are typically either directly or indirectly associated to the corresponding primary_shape_representation of the corresponding Product_view_definitions.

EXPRESS specification:

*)
ENTITY Contextual_shape_representation;
  product_context : product_context_select;
  shape_representing_relationship : Geometric_model_relationship;
DERIVE
  context_representation : geometric_representation_select := shape_representing_relationship.rep_2;
  positioned_representation : geometric_representation_select := shape_representing_relationship.rep_1;
END_ENTITY;
(*

Attribute definitions:

product_context: the role of the product_context_select for the Contextual_shape_representation.

shape_representing_relationship: a role of the Geometric_model_relationship for the Contextual_shape_representation.

context_representation: the Geometric_model in which the representation of the contextual shape is characterized.

positioned_representation: the Geometric_model that contains the representation of the contextual shape in the context representation.

4.3.3 Geometric_composition_with_operator_transformation   EXPRESS-GMapping table

A Geometric_composition_with_operator_transformation is a type of Definitional_representation_relationship and a type of Geometric_relationship_with_operator_transformation.

EXPRESS specification:

*)
ENTITY Geometric_composition_with_operator_transformation
  SUBTYPE OF (Geometric_relationship_with_operator_transformation, Definitional_representation_relationship);
END_ENTITY;
(*

4.3.4 Geometric_composition_with_placement_transformation   EXPRESS-GMapping table

A Geometric_composition_with_placement_transformation is a type of Definitional_representation_relationship and a type of Geometric_relationship_with_placement_transformation.

EXPRESS specification:

*)
ENTITY Geometric_composition_with_placement_transformation
  SUBTYPE OF (Geometric_relationship_with_placement_transformation, Definitional_representation_relationship);
END_ENTITY;
(*

4.3.5 Geometric_model_relationship_with_transformation   EXPRESS-GMapping table

A Geometric_model_relationship_with_transformation is a type of Geometric_model_relationship. Each Geometric_model_relationship_with_transformation is either a Geometric_relationship_with_placement_transformation or a Geometric_relationship_with_operator_transformation

EXPRESS specification:

*)
ENTITY Geometric_model_relationship_with_transformation
  ABSTRACT SUPERTYPE OF (ONEOF (Geometric_relationship_with_placement_transformation,
                                Geometric_relationship_with_operator_transformation))
  SUBTYPE OF (Geometric_model_relationship);
WHERE
  WR1: SELF\Representation_relationship.rep_1.context_of_items :<>: SELF\Representation_relationship.rep_2.context_of_items;
END_ENTITY;
(*

Formal propositions:

WR1: Both geometric representations shall belong to different geometric contexts.

4.3.6 Geometric_placement_model   EXPRESS-GMapping table

A Geometric_placement_model is a type of Geometric_model that contains exactly one Geometric_placement_operation.

NOTE    A Geometric_placement_model can be used by the inherited attribute primary_shape_representation of a Product_occurrence to select a particular Geometric_placement_operation within the Geometric_model of an Assembly_definition. This usage is no longer recommended.

EXPRESS specification:

*)
ENTITY Geometric_placement_model
  SUBTYPE OF (Geometric_model);
  SELF\Representation.items : SET[1:1] OF Geometric_placement_operation;
END_ENTITY;
(*

Attribute definitions:

items: a set of Geometric_placement_operations that the Geometric_placement_model is a collection of. There shall exist exactly one Geometric_placement_operation for the Geometric_placement_model.

4.3.7 Geometric_relationship_with_operator_transformation   EXPRESS-GMapping table

A Geometric_relationship_with_operator_transformation is a type of Geometric_model_relationship_with_transformation where the transformation is explicitly defined by a cartesian_transformation either in 2D or in 3D.

A Geometric_relationship_with_operator_transformation shall not be used for an assembly structure as it might result in shearing, scaling and mirroring of the Geometric_model of the components of the assembly.

EXPRESS specification:

*)
ENTITY Geometric_relationship_with_operator_transformation
  SUBTYPE OF (Geometric_model_relationship_with_transformation);
  transformation : cartesian_transformation;
WHERE
  WR1: SELF\Representation_relationship.rep_1.context_of_items\Geometric_coordinate_space.dimension_count :=: SELF\Representation_relationship.rep_2.context_of_items\Geometric_coordinate_space.dimension_count;
END_ENTITY;
(*

Attribute definitions:

transformation: the cartesian_transformation that identifies the transformation for the Geometric_relationship_with_operator_transformation.

Formal propositions:

WR1: The inherited attributes rep_1 and rep_2 shall have representation values with the same dimensionality.

4.3.8 Geometric_relationship_with_placement_transformation   EXPRESS-GMapping table

A Geometric_relationship_with_placement_transformation is a type of Geometric_model_relationship_with_transformation where the transformation is defined indirectly by one or several pairs of Representation_items that are mapped onto each other.

NOTE 1   In many cases a single pair of Axis_placements is used to define the transformation between the corresponding Geometric_coordinate_spaces of the affected Geometric_models so that the Axis_placements fall together.

NOTE 2   A Geometric_relationship_with_placement_transformation is the preferred mechanism to represent the transformation in an assembly structure as it guarantees that the resulting transformation matrix is not shearing, not scaling and not mirroring.

EXPRESS specification:

*)
ENTITY Geometric_relationship_with_placement_transformation
  SUBTYPE OF (Geometric_model_relationship_with_transformation);
  transformation : Axis_placement_mapping;
WHERE
  WR1: SELF\Representation_relationship.rep_1.context_of_items\Geometric_coordinate_space.dimension_count :=: SELF\Representation_relationship.rep_2.context_of_items\Geometric_coordinate_space.dimension_count;
END_ENTITY;
(*

Attribute definitions:

transformation: a single, set or list of Axis_placement_mappings that define the transformation.

Formal propositions:

WR1: The inherited attributes rep_1 and rep_2 shall have representation values with the same dimensionality.



*)
END_SCHEMA;  -- Contextual_shape_positioning_arm
(*


© ISO 2021 — All rights reserved