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The SEDRIS Data Representation Model
APPENDIX B - Constraints Oct Tree Related Organizing Principle |
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For any oct tree-related organization OTRA, whether an <Oct Tree Related Geometry> or an <Oct Tree Related Features>,
The organization shall have a <Spatial Domain> component, defining the bounding volume that the oct tree is organizing into octants. Since a volume is being specified, this <Spatial Domain> 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 Domain> 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 Domain>. |
| 2.2 | Each octant's <Spatial Domain> 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 Domain> 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 oct tree-related organization shall provide a <Spatial Domain>, so that the data provider specifies the bounding volume that the oct tree is dividing into octants.
Each component representing an octant shall specify a <Spatial Domain>, because although octants are intended to be of equal size, "size" is not invariant under coordinate transformation. The <Spatial Domains>, are necessary to ensure that the boundaries between octants are well-defined when coordinate conversions and transformations are applied.
The <Spatial Domain> instances of the branches and the octants that they represent shall correspond.
These <Spatial Domain> instances shall be 3D, because the concept of an oct tree is inherently 3D.
No Example supplied.
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