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> instance or an <DRM Environment Root> instance. 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> instance 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> instance shall conform exactly to that pattern, up to the point where the summary’s pattern ceases to provide specifics.

The multiplicity field indicates the number of identical instances represented.

Class diagram

Figure 6.216 — 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. 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 five-sided <DRM Polygon> instances. The <DRM Primitive Summary Item> instances indicate common patterns and not is not an enumeration of all the patterns that are present.

  

  Figure 6.217 — <DRM Primitive Summary Item> example