ISO 10303-214:2010(E)

Figure — Arrowleft Figure — Clause 4 Figure — Arrowright

4.2.279 Instance_placement

An Instance_placement is the information pertaining to the placement of a Single_instance, which is defined in its own Cartesian_coordinate_space, in the coordinate space of a reference Product_component.

NOTE A Product_component may be placed by a transformation, using Model_property_association.

The data associated with an Instance_placement are the following:

4.2.279.1 placed_instance

The placed_instance specifies the Single_instance that is placed.

The coordinate system is defined by any Geometric_model or External_geometric_model representing the shape of the placed_instance .

The Geometric_model or External_geometric_model that is referred to, indirectly, by Instance_placement.placement and which defines the local geometry of the Single_instance shall be associated with the Single_instance through an instance of Shape_description_association and of Item_shape.

NOTE If the shape of the Item_instance is not different from the shape of the Design_discipline_item_definition referred to by the instance of Item_shape the Geometric_model representing this shape is shared.

See instance_placement to single_instance for the application assertion.

4.2.279.2 placement

The placement specifies the Geometric_model_relationship_with_transformation or the Template_instance that defines the position of the 'placed_instance' relatively to the 'reference_product_component'. In the case of Template_instance, the scale shall be omitted or set to 1.0.

The Geometric_model associated with the 'reference_product_component', in which the Geometric_model or External_model of the placed instance is located, shall contain Axis_placement instances locating each placed instance and may contain additional instances of geometric entities, describing shape aspects relevant in the context of the 'reference_product_component'.

EXAMPLE The Geometric_model associated with a reference_product_component 'car engine' may contain Axis_placement instances locating the gear box and the crankshaft and additional geometric information representing the envelope box allowed for the car engine.

See instance_placement to geometric_model_relationship_with_transformation and instance_placement to template_instance for the application assertions.

There shall be exactly one object that defines the placement for an Instance_placement.

4.2.279.3 reference_product_component

The reference_product_component specifies the Product_component that specifies indirectly the reference coordinate space. The coordinate system of the reference_product_component that serves as a reference for the placement shall be specified by an External_geometric_model or a Geometric_model referenced by a Model_property_association. The 'definition' of the Model_property_value shall be a General_property with a 'property_type' of 'positioning'. Alternatively the coordinate system is defined by the shape of the reference_product_component .

See instance_placement to product_component for the application assertion.

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