An orientable boundary surface of a region. A single region may have more than one shell, as in the case of a solid object with a void contained within it. A region may have no shell only where all space exists as a single region, as in the initial state where no modeling has been done, or after all components of a model have been deleted, or if only faces, rings, edges, vertices have been created. A shell consists of one face or of a connected set of faces which form a closed volume.

earth_model (I, V: SET[0:?] earth_model(spatial_object))

Indicates various earth models which include this spatial representation. Each shell may be part of one or more earth_model. Inherited from spatial_object.


face (V: SET[0:?] face(shell))

Defines the faces which compose this shell. Each shell may be composed of one or more face.


intersection_role (I, V: SET[0:?] space_time_operation(intersecting_object))

Indicates a space/time operation for which the object is involved as an intersecting agent. For projection, this is the screen on which an object is being projected. For proximity, this is the magnet object. Each shell may be the intersecting object for one or more space_time_operation. Inherited from topological_object.


other_composite_spatial_object (I, V: SET[0:?] other_composite_spatial_object(composite_object))

Defines the set of composite spatial objects of which this spatial object is a component. Each shell may be a component of one or more other_composite_spatial_object. Inherited from spatial_object.


primary_role (I, V: SET[0:?] space_time_operation(primary_object))

Indicates a space/time operation for which the object is involved as a primary agent. For degeneration, this object is being degenerated. For projection, this object is being projected onto another object. For proximity, this is the container object. Each shell may be the primary object for one or more space_time_operation. Inherited from topological_object.


primary_topological_relationship (I, V: SET[0:?] topological_relationship(primary_topological_object))

Indicates a topological relationship in which the topologic object has the role of primary agent. For an object intersection type of "inside" this is the containing role (e.g., if a city is inside a county then the county would be the primary agent). For all other object intersection types the roles are symmetrical and both relationships must be searched for a particular object. For example, if a wellbore and a formation overlap then either could be chosen as the primary agent with the other chosen as the secondary agent. Each shell may be primarily involved in one or more topological_relationship. Inherited from topological_object.


pty_geometry_3d_shell (V: SET[0:?] pty_geometry_3d_shell(shell))

Each shell may have a property of one or more pty_geometry_3d_shell.


secondary_topological_relationship (I, V: SET[0:?] topological_relationship(secondary_topological_object))

Indicates a topological relationship in which the object is in the role of secondary agent. For an object intersection type of "inside" this is the contained role (e.g., if a well is inside a field then the well would be the secondary agent). For all other object intersection types the roles are symmetrical and both relationships must be searched for a particular object. For example, if a wellbore and a formation overlap then either could be chosen as the secondary agent with the other chosen as the primary agent. Each shell may be involved in one or more topological_relationship. Inherited from topological_object.


shell_region_binding (V: SET[0:?] shell_region_binding(shell))

Indicates various usages of this shell to delimit regions. Each shell may provide the bounds for one or more shell_region_binding.


source_space_time_operation (I, V: BAG[0:1] space_time_operation(resulting_object))

Indicates the space/time operation from which a topological object was the result. For addition, this is the union of two objects. For degeneration, this is the degenerate object. Each shell may be the result of one space_time_operation. Inherited from topological_object.

Local rules:

Abstract supertype:
Each SHELL must be instantiated as one of its subtypes. These subtypes are: earth_position_shell, other_shell, wellbore_shell
Supertype path(s):
topological_object > spatial_object > simple_spatial_object > shell.

Entity replicated into subtype tables (@shell).

Referenced in Diagrams:

• SM1: Spatial Model Topology Hierarchy
• SM2: Spatial Model Properties
• SM5: Other Spatial Object