4 Drawing definition schema

4.1 General

The subject of the drawing_definition_schema is the identification, description, organization, and administration of drawing revisions. It identifies drawing revisions and drawing sheet revisions that comprise a drawing. It describes the relationship between revisions of drawings and sheets. In short, this schema provides resources for the definition and management of the drawing.

Each implementation of an AP that uses this schema and that encodes entity names shall use the encoding specified in Annex A. Each reference to this schema in an open system shall use the identifier encoding specified in Annex B. This schema is illustrated in Annex D using the EXPRESS-G notation.

REFERENCE FROM support_resource_schema    --  ISO 10303-41
  (label,
   text,
   identifier,
   bag_to_set);



REFERENCE FROM representation_schema    --  ISO 10303-43
  (mapped_item,
   representation_relationship,
   representation);



REFERENCE FROM presentation_organization_schema    --  ISO 10303-46
  (area_in_set,
   presentation_area,
   presentation_set,
   presentation_representation_relationship);
(*



NOTE 1   The schemas referenced above are specified in the following parts:

support_resource_schema	ISO 10303-41
representation_schema	ISO 10303-43
presentation_organization_schema	ISO 10303-46

NOTE 2   See Annex D for a graphical representation of this schema.

4.2 Fundamental concepts and assumptions

A drawing is a draughting-specific presentation of information about a product including information used to interpret the presentation. A drawing can be partitioned or divided into a number of drawing sheets. Drawings are configured and administered by versions. Each drawing, including its drawing sheets, may have many versions. Versions of drawings and drawing sheets are known as revisions. A drawing is a revision whether it be initial or the result of change. If any drawing sheet is added, changed, or deleted, a new revision of the drawing may be established. The ability to identify and describe a drawing revision is provided, independently of organizational practices.

A revised drawing or drawing sheet is considered a successor of the original drawing or drawing sheet. The revisions of a drawing or drawing sheet may be sequentially ordered.

Drawing and drawing sheet revisions may have a draughting-specific title or description. A draughting title may change for subsequent revisions of the drawing or drawing sheet.

4.3 drawing_definition_schema type definition

4.3.1 draughting_titled_item   

EXPRESS specification:

*)
TYPE draughting_titled_item = SELECT
   (drawing_revision,
    drawing_sheet_revision);
END_TYPE;
(*

4.4 drawing_definition_schema entity definitions

4.4.1 draughting_title   

EXAMPLE 1   A drawing containing the mechanical compatibility information for a safety switching device may be given a text description such as "MECHANICAL COMPATIBILITY, SAFETY SWITCH", where the language is English.

EXPRESS specification:

*)
ENTITY draughting_title;
  items : SET[1:?] OF draughting_titled_item;
  language : label;
  contents : text;
END_ENTITY;
(*

Attribute definitions:

items: the drawing sheets or revisions to which the title applies.

language: a label indicating the language used for terms in the contents of the draughting_title in the Alpha-3 bibliographic code of ISO 639-2.

contents: the text of the title.

EXAMPLE 2   "BRACKET - CABLE, ASSY OF" and "DISK - LPC, 4 STG" are examples of titles.

4.4.2 drawing_definition   

NOTE 1   When the need for a drawing is identified, a drawing definition begins its existence when the organization assigns a drawing number.

EXPRESS specification:

*)
ENTITY drawing_definition;
  drawing_number : identifier;
  drawing_type : OPTIONAL label;
END_ENTITY;
(*

Attribute definitions:

drawing_number: an identifier for the versions of a drawing.

NOTE 2   Drawing numbers themselves are often composed of parts such as: a type prefix, a part number (or stem), and a suffix. Its composition is provided by the originating organization.

EXAMPLE 1   "CK123456-789", "DL-S12345", "1B5102-04", and "1D55500" are examples of drawing number strings.

drawing_type: a label used to describe the functional categorization of the drawing.

NOTE 3   A type of drawing is used to communicate a specific portion of the information about a product. For a printed wiring assembly, the functional aspects are communicated by means of a schematic diagram whereas the physical aspects are communicated by means of another drawing type.

EXAMPLE 2   "SCHEMATIC DIAGRAM", "SITE PLAN", "DETAIL", and "ASSEMBLY" are examples of drawing-type labels. Additional examples for drawing-type labels may be found in ISO 10209-1.

4.4.3 drawing_revision   

EXPRESS specification:

*)
ENTITY drawing_revision
  SUBTYPE OF (presentation_set);
  revision_identifier : identifier;
  drawing_identifier : drawing_definition;
  intended_scale : OPTIONAL text;
UNIQUE
  UR1: revision_identifier, drawing_identifier;
END_ENTITY;
(*

Attribute definitions:

revision_identifier: an identifier for the revision of the drawing.

NOTE    The values for this representation may be comprised of any allowable characters. Any limit or restrictions must be specified in an Application Protocol. Typically, the revision identifier is an alphanumeric string.

EXAMPLE 1   The revision identifier may be "A", "AA", "2.4", or could be "31".

drawing_identifier: an identifier for the drawing.

intended_scale: a text description of the intended drawing scale where the description is for information only.

EXAMPLE 2   "1/4", "100:1", "NONE" are drawing scale examples.

Formal propositions:

UR1: The identifier for a version of a drawing shall be unique for that drawing.

EXAMPLE 3   A drawing revision identified by the letter "A" is the only drawing revision identified by that letter in the set of revisions of a particular drawing.

4.4.4 drawing_revision_sequence   

EXAMPLE    If two drawing revisions were identified by revision identifiers equal to A and B successively, the drawing revision identified by A would play the role of predecessor and the drawing revision identified by B would play the role of successor in the sequence of drawing revisions.

EXPRESS specification:

*)
ENTITY drawing_revision_sequence;
  predecessor : drawing_revision;
  successor : drawing_revision;
WHERE
  WR1: predecessor :<>: successor;
END_ENTITY;
(*

Attribute definitions:

predecessor: a version of a drawing which precedes another version of a drawing.

successor: a version of a drawing which succeeds another version of a drawing.

NOTE    A drawing version (i.e., drawing_revision) may precede or succeed another version of the same drawing or a version of a different drawing (i.e., not identified by the same drawing_definition) in a logical sequence of drawings.

Formal propositions:

WR1: A particular revision of a drawing shall not precede nor succeed itself.

4.4.5 drawing_sheet_revision   

NOTE 1   As a type of area_in_set, the drawing_sheet_revision provides the information necessary to present a version of a drawing sheet. It also specifies the administrative data used to manage a version of a drawing sheet, with respect to the drawing revision.

EXPRESS specification:

*)
ENTITY drawing_sheet_revision
  SUBTYPE OF (presentation_area);
  revision_identifier : identifier;
WHERE
  WR1: SIZEOF( QUERY(item <* SELF\representation.items | ('REPRESENTATION_SCHEMA.MAPPED_ITEM' IN (TYPEOF(item))) AND ('DRAWING_DEFINITION_SCHEMA.DRAWING_SHEET_REVISION' IN (TYPEOF(item\mapped_item.mapping_source.mapped_representation)))))=0;
END_ENTITY;
(*

Attribute definitions:

revision_identifier: an identifier for the revision of a drawing sheet.

Formal propositions:

WR1: A drawing_sheet_revision shall not have another drawing_sheet_revision mapped into it.

NOTE 2   For requirements regarding the mapped_item see of ISO 10303-43.

4.4.6 drawing_sheet_revision_sequence   

EXAMPLE    An instance of drawing_sheet_revision_sequence where rep_1 is an instance of drawing_sheet_revision with a revision_identifier of "A" and rep_2 is an instance of drawing_sheet_revision with a revision_identifier of "B" represents the successive relationship between the predecessor (revision "A") and successor (revision "B").

EXPRESS specification:

*)
ENTITY drawing_sheet_revision_sequence
  SUBTYPE OF (representation_relationship);
WHERE
  WR1: SELF\representation_relationship.rep_1 :<>: SELF\representation_relationship.rep_2;
  WR2: 'DRAWING_DEFINITION_SCHEMA.DRAWING_SHEET_REVISION' IN TYPEOF (SELF\representation_relationship.rep_1);
  WR3: 'DRAWING_DEFINITION_SCHEMA.DRAWING_SHEET_REVISION' IN TYPEOF (SELF\representation_relationship.rep_2);
END_ENTITY;
(*

Formal propositions:

WR1: The drawing_sheet_revisions that are related shall be different instances.

WR2: The rep_1 shall be a drawing_sheet_revision.

WR3: The rep_2 shall be a drawing_sheet_revision.

4.4.7 drawing_sheet_revision_usage   

EXPRESS specification:

*)
ENTITY drawing_sheet_revision_usage
  SUBTYPE OF (area_in_set);
  sheet_number : identifier;
UNIQUE
  UR1: sheet_number, SELF\area_in_set.in_set;
WHERE
  WR1: ('DRAWING_DEFINITION_SCHEMA.DRAWING_SHEET_REVISION' IN TYPEOF(SELF\area_in_set.area)) AND ('DRAWING_DEFINITION_SCHEMA.DRAWING_REVISION' IN TYPEOF (SELF\area_in_set.in_set));
END_ENTITY;
(*

Attribute definitions:

sheet_number: an identifier indicating the position of a drawing sheet in a sequence of drawing sheets which are part of a drawing.

NOTE    Drawing sheets are not restricted to being numbered contiguously. Sheet numbering is business practice specific.

EXAMPLE    Sheets numbered 1,2,4,5... where sheet 3 has been deleted is an example of a valid set of drawing sheet numbers for a drawing revision.

Formal propositions:

UR1: No drawing_revision shall have two drawing_sheet_revisions identified by the same sheet_number.

WR1: Only drawing_sheet_revisions shall be used as a numbered sheet of a drawing_revision and only drawing_revisions shall use drawing_sheet_revisions as a numbered sheet.

4.5 drawing_definition_schema rule definition

4.5.1 drawing_sheets_not_nested

EXPRESS specification:

*)
RULE drawing_sheets_not_nested FOR
(presentation_representation_relationship);
WHERE
  WR1: SIZEOF( QUERY(p_r_r <* presentation_representation_relationship | ('DRAWING_DEFINITION_SCHEMA.DRAWING_SHEET_REVISION' IN (TYPEOF(p_r_r.rep_1))) AND ('DRAWING_DEFINITION_SCHEMA.DRAWING_SHEET_REVISION' IN (TYPEOF( p_r_r.rep_2))))) = 0;
END_RULE;
(*

Argument definitions:

presentation_representation_relationship : the set of all instances of presentation_representation_relationship.

Formal propositions:

WR1: A drawing_sheet_revision shall not play the role of parent representation in a presentation_representation_relationship where the child representation is also a drawing_sheet_revision.

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