Application module: Contextual shape positioning | ISO/TS 10303-1027:2021(E) © ISO |
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;
(*
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.
This subclause specifies the ARM types for this application module. The ARM types and definitions are specified below.
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;
(*
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;
(*
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.
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.
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.
EXPRESS specification:
*)
ENTITY Geometric_composition_with_operator_transformation
SUBTYPE OF (Geometric_relationship_with_operator_transformation, Definitional_representation_relationship);
END_ENTITY;
(*
EXPRESS specification:
*)
ENTITY Geometric_composition_with_placement_transformation
SUBTYPE OF (Geometric_relationship_with_placement_transformation, Definitional_representation_relationship);
END_ENTITY;
(*
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.
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.
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.
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
(*
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