|
The SEDRIS Data Representation Model
APPENDIX B - Constraints Octant Related Organizing Principle |
|---|
For any octant-related organization instance OTRA, whether an instance of <Octant Related Geometry> or of <Octant Related Features>,
The organization shall have a <Spatial Extent> component, defining the bounding volume that the octant is organizing into octants. Since a volume is being specified, this <Spatial Extent> shall be specified in terms of <Location 3D> instances.
Each branch of OTRA shall comply with the following constraints.
| 2.1 | Each component representing an octant shall have a <Spatial Extent> component, specified in terms of <Location 3D> instances. In the case of octants represented by <Geometry Model Instance> or <Feature Model Instance> instances, the <Model> being referenced shall have the <Spatial Extent>. |
| 2.2 | Each octant's <Spatial Extent> is distinct from that of all of its siblings, such that they do not overlap or intersect, except that they may have a common boundary. |
| 2.3 | Consider the bounding volume defined by the <Spatial Extent> of OTRA, as divided into 8 octants of equal size in their native SRF. |
The strict_organizing_principle and unique_descendants field values of OTRA shall be SE_TRUE.
The octant-related organization shall provide a <Spatial Extent>, so that the data provider specifies the bounding volume that the octant is dividing into octants.
Each component representing an octant shall specify a <Spatial Extent>, because although octants are intended to be of equal size, "size" is not invariant under coordinate transformation. The <Spatial Extent> instances are necessary to ensure that the boundaries between octants are well-defined when coordinate conversions and transformations are applied.
The <Spatial Extent> instances of the branches and the octants that they represent shall correspond.
These <Spatial Extent> instances shall be 3D, because the concept of an octant is inherently 3D.
No Example supplied.
|