Table 6.319—DRM_Vertex_With_Component_Indices
Property |
Description |
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Superclass |
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Class |
· <DRM Vertex With Component Indices> |
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Subclass |
· none |
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Definition |
A specialization of the <DRM Base Vertex> class, used to indicate that one or more of the <DRM Base Vertex>'s components are contained within a <DRM Hierarchical Table> instance found higher in the aggregation tree of the transmittal, and are thus referred to by "component index" rather than by direct attachment to the <DRM Vertex With Component Indices>. The purpose of this specialization is to make reuse and sharing of these components explicit, by placing them in appropriate <DRM Hierarchical Table> instances for reference by indexing rather than direct aggregation. Each index field value of a <DRM Vertex With Component Indices> instance is either a sentinel value, COMPONENT_IS_AGGREGATED, or an index into some table. a. In lieu of a valid index value, an index field may be set to the sentinel value COMPONENT_IS_AGGREGATED which indicates that the corresponding component is not a reference to a table. This sentinel is used both for cases where the <DRM Vertex With Component Indices> instance has no components of the specified class, and where it directly references such components rather than referring to some <DRM Hierarchical Table>. b. An index field may be an actual index into the collection of <DRM Hierarchical Table> instances which lie above the <DRM Vertex With Component Indices> in the aggregation tree. An index is resolved to an actual component by traversing up the aggregation tree until the correct subclass of <DRM Hierarchical Table> (with respect to the particular index being evaluated) is encountered, such that the span of the <DRM Hierarchical Table> instance includes the index being evaluated. If the <DRM Hierarchical Table> does span the index being evaluated, then its start_index is used to determine which of its ordered components corresponds to the requested index. Note that for component relationships defined with a cardinality of 0..N, the corresponding subclasses of <DRM Hierarchical Table> accomodate this cardinality, the corresponding <DRM Hierarchical Table> subclasses may aggregate a "set" of target components as well as individual instances. |
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Example(s) |
· A producer of a transmittal wants to reuse the <DRM Location 3D> objects for <DRM Vertex>s of a group of <DRM Polygon>. One possible construction is given below. |
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Inherited field elements |
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Field elements |
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Associated to (one-way) (inherited) |
· none |
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Associated to (one-way) |
· none |
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Associated by (one-way) (inherited) |
· none |
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Associated by (one-way) |
· none |
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Associated with (two-way) (inherited) |
· zero or one <DRM Geometry Node> |
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Associated with (two-way) |
· none |
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Composed of (two-way) (inherited) |
· zero or more <DRM Colour>s · zero or one <DRM Conformal Behaviour · zero or more <DRM Property Table Reference>s · zero or one <DRM Reference Vector> · zero or more {ordered} <DRM Texture Coordinate>s |
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Composed of (two-way) |
· zero or one <DRM Location> |
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Composed of (two-way metadata) (inherited) |
· none |
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Composed of (two-way metadata) |
· none |
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Component of (two-way) (inherited) |
· zero or more <DRM Arc>s · zero or more <DRM Finite Element Mesh>s · zero or more <DRM Line>s · zero or more <DRM Polygon>s |
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Component of (two-way) |
· none |
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Constraints |
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Notes |
none |
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Class diagram |