Defines a relationship between two or three objects. The operation (e.g., intersection, addition, subtraction) of a primary object on an intersecting object produces a resulting object. For example, an edge is an object resulting from the intersection between two faces.

ref_space_time_operation (M, K: ref_space_time_operation)

This describes the kind of operation. Allowable operations include: intersection, proximity, projection, degeneration, addition and subtraction.


resulting_object (M, K: topological_object(source_space_time_operation))

Indicates the topological object which resulted from a space/time operation. For intersection, this points to the object which represents the intersection of the two objects. For degeneration, this points to the object which is a degenerated form of the primary object. For projection, this points to the object which represents the projection of the primary object onto the intersecting object. For subtraction, this points to the object which is the result of subtracting from the primary object, the intersection between the primary and the intersecting object. For addition, this represents the union of the primary and intersecting objects. For proximity, this points to the object which is a subset of the primary object which is near the intersecting object. Each space_time_operation must result in one topological_object.


primary_object (M: topological_object(primary_role))

Indicates the topological object involved in a space/time operation in the role of primary agent (i.e., the thing we start with). For degeneration, this points to the object which is being degenerated. For projection, this points to the object which is being projected onto another object (the screen). For intersection and addition, this points to one of the objects participating in the relationship (i.e., both relationships must be searched to find a particular object). For proximity, this points to the container object which is near the intersecting object and of which the resulting object is a subset. For subtraction, this points to the object from which we are subtracting the intersection of the intersecting object. Each space_time_operation must use primarily one topological_object.


description (O: ndt_comment)

Comment associated with the intersection.


projection_vector (O: ndt_spherical_coordinates_complex_angle)

The angle of projection. Depending upon the dimension of the space, the angle will be defined by one, two or three components.


data_collection (I, V: SET[0:?] data_collection(collection_content))

Indicates the data collections that include this instance of E and P data. Each space_time_operation may be a member of one or more data_collection. Inherited from e_and_p_data.


graphical_element (I, V: SET[0:?] graphical_element(depicted_object))

Specifies one or more graphical elements which are depicting this data item. Each space_time_operation may be depicted by one or more graphical_element. Inherited from e_and_p_data.


intersecting_object (O: topological_object(intersection_role))

Indicates the topological object involved in a space/time operation in the role of intersecting agent. For projection, this points to the screen on which the primary object is being projected. For intersection and addition, this points to one of the objects participating in the relationship (i.e., both relationships must be searched to find a particular object). For subtraction, this points to the object which is subtracted from the primary object. For proximity, this points to the magnet object that the primary object is near. Each space_time_operation may be made on one topological_object.

Local rules:

Uniqueness Constraint
ref_space_time_operation, resulting_object
Supertype path(s):
e_and_p_data > association > space_time_operation.

Entity projects as table SPACE_TIME_OPR.

Referenced in Diagrams:

• SM1: Spatial Model Topology Hierarchy