Definition

1. Consider a perimeter-related organization P, which is either a <Perimeter Related Features> instance or a <Perimeter Related Geometry> instance.

   1. The regions defined by the branches of P shall not overlap; that is, the <Perimeter Data> link objects on the branches shall define regions that do not overlap.

   2. For each branch of P, every primitive within that branch shall have a spatial extent overlapping that of the branch.

   3. If the strict_organizing_principle of P is SE_TRUE, for each branch of P, each primitive within the branch shall have a spatial extent fully contained within that defined by the <Perimeter Data> link object corresponding to the branch.

      If the strict_organizing_principle of P is SE_FALSE, no guarantees exist as to how accurately the DRM objects of the component tree rooted at P were placed into their "sorted bins" (the branches of P), apart from that specified by 1 (above).

2. Consider P.

   1. If P is a <Perimeter Related Features> instance, and the same <Feature Representation> instance belongs to more than one of its branches, the unique_descendants and strict_organizing_principle flags of P shall be set to SE_FALSE.

   2. If P is a <Perimeter Related Geometry> instance, and the same <Geometry Representation> instance belongs to more than one of its branches, the unique_descendants and strict_organizing_principle flags of P shall be set to SE_FALSE.

Rationale

1. In a hypothetical perimeter-related organization with overlapping <Perimeter Data>, determining which branch a given object belongs to would be ambiguous, so that the usefulness of the as a means of organizing primitives would be defeated.

2. Each branch of a perimeter-related organization is intended to organize objects that fall within the specified perimeter for that branch.

3. For perimeter-related organizations that interact with topology, the regions defined by the <Perimeter Data> link objects are intended to fully partition the topological surface.

4. The strict_organizing_principle field of the <Perimeter Related Features> class and the <Perimeter Related Geometry> class was designed to allow the use of perimeter-related organization, even when a few primitives cross the boundaries of the organizing principle.

Example

See the <Perimeter Related Geometry> class for examples.

FAQs

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