Class

• <DRM Primitive Summary Item>

Superclass

• <DRM Base Summary Item>

Subclass

• None.

Definition

An instance of this DRM class specifies a common pattern of primitive objects that appear in the scope being summarized, which may be either a <DRM Model> or an <DRM Environment Root>. A <DRM Primitive Summary Item> instance represents one or more instances of the class specified by its drm_class field that conform to the specified pattern.

A <DRM Primitive Summary Item> may represent only instances of <DRM Primitive Geometry>, <DRM Primitive Feature>, their subclasses, and the classes that may appear in their component trees. <DRM Primitive Summary Item> instances are combined to form a hierarchy mirroring that of the primitive instances that they represent, such that the summary is a compressed form of the actual hierarchy.

Since a <DRM Primitive Summary Item> instance may represent many instances of the primitive that it summarizes, it has a multiplicity field, indicating how many instances of the pattern it represents. Note that all instances represented by a given <DRM Primitive Summary Item> shall conform exactly to that pattern, up to the point where the summary's pattern ceases to provide specifics.

Class diagram

Figure 6.213 — DRM_Primitive_Summary_Item

Constraints

• Primitive Summary Item constraints
• Publishable Object

Example(s)

• Summary of a common <DRM Polygon> structure pattern within a <DRM Model>.

  In this case, the pattern indicates that a data consumer can expect to see triangles. Note that other patterns can be present; in this particular example, the <DRM Model> contains not only triangles, but other types of <DRM Polygon> instances, such as quadrilaterals and even 5-sided <DRM Polygon> instances. The <DRM Primitive Summary Item> instances are just indicating common patterns; they're not enumerating all the patterns that are present.

  

  Figure 6.214 — <DRM Primitive Summary Item> example