Rule Name: Non Crossing Aggregations

Definition

Aggregations can't cross Models and/or Environment Root.

Rationale

Why would a generic Model use pieces of the terrain? If the Model is intended to be instanced as part of the terrain of the Environment Root, then Environment Root should instance the Model, not duplicate parts of it.

If a Model or Environment Root needs to use another Model, use a Feature Model Instance or Geometry Model Instance. If only a portion of the Model is desired for reuse, it should be a Model of its own.

Example

1. If a Polygon is under Environment Root, no Model can use the Polygon.
2. If a Polygon is under a Model, Environment Root cannot use the Polygon directly. A Model's components can be accessed only via Geometry Model Instances and/or Feature Model Instances.
3. If a Polygon is under a Model, no other Model can use that Polygon directly. A Model's components can be accessed only via Geometry Model Instances and/or Feature Model Instances.

FAQs