2.3.1 AP217 ARM Review (by Ron Wood)
Principle ARM Changes
・Standardise structure of the user-defined attribute handling.
・Correction of use of measures/measures_with_unit.
⇒Subtypes of Definition use … measure and inherit the Definition's Unit attribute.
⇒Non-subtypes of Definition use … _measure_with_unit.
・Eliminate restatement of non-qualified inherited attributes:
⇒SELF\Item_structure. items.
⇒SELF\Item_relationship. item_1; item_2.
NOTE: These must be optional.
・Correct misuse of OPTIONAL vs S [0: ?]
⇒Many attributes were both.
⇒Standard for attributes where there may or not be members of an aggregate is attribute S [0: ?], *NOT* OPTIONAL attribute S [1: ?]
・Added some missing types, e.g.
⇒Piping_system_relationship (such that system_relationship was not left as ABS and otherwise unspecified).
⇒Specific_butt_port.
⇒etc.
・Remodelling of occurrence_to_specific relationships.
⇒Previous model incorrectly related one specific entities with multiple occurrence entities, all of which used the same transformation.
⇒… _relationships now relate to one occurrence entity and are potentially referred to by one specific entity.
・Piping_specifications
⇒Remodelled to allow for external references to specifications
・Shape representations
⇒Detail_shape_representation_items are:
・manifold_solid_brep
・csg_solid
⇒Diagram_shape_representation_items are:
・line
・b_spline_curve
・trimmed_curve
・composite_curve
・Other minor changes
・Renamed many "identifier" attributes as "id"
・Changed aggregation specifications on many attributes from BAG or LIST to SET.
・Renamed some attributes to avoid use of reserved words (e.g. "reference").
・Removed use of performances BB.
More details can be found in Ship/LH-6.
