Entity space_time_operation

• 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.

Attribute                                 Flags   Data Type

From association:
   data_collection                        IV      set[0 .. N] of (data_collection)

                                          Indicates the data collections that include this
                                          instance of E and P data. 

   graphical_element                      IV      set[0 .. N] of (graphical_element)

                                          Specifies one or more graphical elements which
                                          are depicting this data item. 


description                                       ndt_comment

                                          Comment associated with the intersection. 

projection_vector                         N       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. 

ref_space_time_operation                  MU      ref_space_time_operation

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

intersecting_object                               topological_object

                                          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. 

resulting_object                          MU      topological_object

                                          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. 

primary_object                            M       topological_object

                                          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. 

End of entity space_time_operation

M - mandatory, U - unique, I - inherited, V - inverse, N - named type