4 Information requirements

This clause specifies the information requirements for the Draughting element application module. The information requirements are specified as the Application Reference Model (ARM) of this application module.

NOTE 1  A graphical representation of the information requirements is given in Annex C.

NOTE 2  The mapping specification is specified in 5.1. It shows how the information requirements are met by using common resources and constructs defined or imported in the MIM schema of this application module.

This clause defines the information requirements to which implementations shall conform using the EXPRESS language as defined in ISO 10303-11. The following begins the Draughting_element_arm schema and identifies the necessary external references.

4.1 Required AM ARMs

The following EXPRESS interface statements specify the elements imported from the ARMs of other application modules.

EXPRESS specification:

*)
USE FROM Associative_text_arm;    --  ISO/TS 10303-1132



USE FROM Curve_appearance_arm;    --  ISO/TS 10303-1003
(*



NOTE 1   The schemas referenced above are specified in the following part of ISO 10303:

Associative_text_arm	ISO/TS 10303-1132
Curve_appearance_arm	ISO/TS 10303-1003

NOTE 2   See Annex C, Figures C.1and C.2 for a graphical representation of this schema.

4.2 ARM type definitions

This subclause specifies the ARM types for this application module. The ARM types and definitions are specified below.

4.2.1 annotation_plane_element   

The annotation_plane_element type allows for the designation of the data types Draughting_callout and Styled_element.

EXPRESS specification:

*)
TYPE annotation_plane_element = SELECT
   (Draughting_callout,
    Styled_element);
END_TYPE;
(*

4.2.2 de_appearance_select   

The de_appearance_select type is an extension of the appearance_select type. It adds the data types Curve_appearance, Point_appearance, and Text_style to the list of alternate data types.

EXPRESS specification:

*)
TYPE de_appearance_select = SELECT BASED_ON appearance_select WITH
   (Curve_appearance,
    Point_appearance,
    Text_style);
END_TYPE;
(*

4.2.3 draughting_callout_content_select   

The draughting_callout_content_select type is an extensible list of alternate data types that allows for the designation of the data types Annotation_curve and Annotation_text_occurrence.

NOTE   The list of entity data types may be extended in application modules that use the constructs of this module.

EXPRESS specification:

*)
TYPE draughting_callout_content_select = EXTENSIBLE GENERIC_ENTITY SELECT
   (Annotation_curve,
    Annotation_text_occurrence);
END_TYPE;
(*

4.2.4 plane_or_planar_box   

The plane_or_planar_box type allows for the designation of the data types Planar_box and Plane.

EXPRESS specification:

*)
TYPE plane_or_planar_box = SELECT
   (Planar_box,
    Plane);
END_TYPE;
(*

4.3 ARM entity definitions

This subclause specifies the ARM entities for this module. Each ARM application entity is an atomic element that embodies a unique application concept and contains attributes specifying the data elements of the entity. The ARM entities and definitions are specified below.

4.3.1 Annotation_fill_area   

EXPRESS specification:

*)
ENTITY Annotation_fill_area
  SUBTYPE OF (Detailed_geometric_model_element);
  boundaries : SET[1:?] OF Curve;
END_ENTITY;
(*

Attribute definitions:

boundaries: a set of closed Curves that define the inner and outer boundaries of the fill area. There shall exist at least one Curve for the Annotation_fill_area.

4.3.2 Annotation_plane   

An Annotation_plane is a type of Annotation_element for the purpose of grouping annotation elements within a 3D coordinate space. The plane may be bounded by a rectangle and styled so that it becomes visible. The interpretation for text in the plane shall be that x axis is the “line that is being written on”, indicating the reading direction. The interpretation shall be that the y axis points upward from the base to the top of the characters. The interpretation shall be that the z axis points towards the reader. Elements referenced by Annotation_plane shall be in planes that are parallel to the Annotation_plane with the exception of leader lines which need not be parallel to the Annotation_plane.

NOTE    In the case of leader lines that are not parallel to the Annotation_plane the receiving system may need to project them to the relevant plane.

An Annotation_plane may satisfy the requirements for an annotation plane specified in ISO 16792 when all the members of elements are intended to be on the same plane and only numeric accuracy prevents the data from being co-planar.

EXPRESS specification:

*)
ENTITY Annotation_plane
  SUBTYPE OF (Annotation_element);
  elements : OPTIONAL SET[1:?] OF annotation_plane_element;
  SELF\Styled_element.element : plane_or_planar_box;
END_ENTITY;
(*

Attribute definitions:

elements: specifies a role of the annotation_plane_element for the Annotation_plane. There shall exist one or more annotation_plane_elements for the Annotation_plane. The value of this attribute need not be specified.

element: an attribute inherited from the Styled_element shall be redeclared as the plane_or_planar_box for the Annotation_plane.

4.3.3 Dimension_curve   

A Dimension_curve is a type of Annotation_curve. A Dimension_curve is a curve that is used for the graphical representation of a dimension. If necessary, it includes the additional symbology needed to show the extent of the dimension.

EXAMPLE    Figure 1 shows the use of a Dimension_curve in a drawing.

EXPRESS specification:

*)
ENTITY Dimension_curve
  SUBTYPE OF (Annotation_curve);
  terminator : SET[0:2] OF Terminator;
END_ENTITY;
(*

Attribute definitions:

terminator: specifies the Terminator for the Dimension_curve. There shall exist not more than two Terminators for the Dimension_curve.

4.3.4 Dimension_curve_directed_callout   

EXPRESS specification:

*)
ENTITY Dimension_curve_directed_callout
  SUBTYPE OF (Draughting_callout);
  dimension_curve : Dimension_curve;
WHERE
  WR1: dimension_curve IN SELF\Draughting_callout.contents;
END_ENTITY;
(*

Attribute definitions:

dimension_curve: the dimension line of the draughting callout.

Formal propositions:

WR1: The dimension_curve must be in the list of items defined in attribute contents.

4.3.5 Draughting_callout   

A Draughting_callout is a type of Representation_item. A Draughting_callout is a human-interpretable collection of annotation curves, symbols, and text that presents product requirements or information used to interpret the drawing. A Draughting_callout may be either a Dimension_curve_directed_callout or a Leader_directed_callout or a Projection_directed_callout.

EXAMPLE    Figure 2 shows typical Draughting_callout objects on a drawing.

EXPRESS specification:

*)
ENTITY Draughting_callout
  SUPERTYPE OF (ONEOF (Dimension_curve_directed_callout,
                       Leader_directed_callout,
                       Projection_directed_callout))
  SUBTYPE OF (Representation_item);
  contents : LIST[1:?] OF draughting_callout_content_select;
END_ENTITY;
(*

Attribute definitions:

contents: specifies the draughting_callout_content_select that form the Draughting_callout. There shall exist one or more draughting_callout_content_select for the Draughting_callout.

4.3.6 Fill_area   

A Fill_area is a type of Annotation_element. A Fill_area is a bounded area containing colouring, hatching, or tiling.

NOTE    A Fill_area communicates some aspect of a physical part characteristic or distinguishes it from its surroundings.

EXAMPLE    Figure 3 depicts some fill area styles.

EXPRESS specification:

*)
ENTITY Fill_area
  SUBTYPE OF (Annotation_element);
  SELF\Styled_element.element : Annotation_fill_area;
  reference_point : Point;
END_ENTITY;
(*

Attribute definitions:

element: an attribute inherited from the Styled_element shall be redeclared as the Annotation_fill_area for the Fill_area.

reference_point: specifies a point within the fill area, used in the placement and initiation of the fill area appearance. The reference point is a point through that a line of a hatching pattern shall pass or at which the origin of a tile shall be located. The reference point also establishes the point at which the first visible segment of a line font used as the curve appearance for a hatching pattern starts.

4.3.7 Generic_annotation_curve   

EXPRESS specification:

*)
ENTITY Generic_annotation_curve
  SUBTYPE OF (Annotation_curve);
END_ENTITY;
(*

4.3.8 Leader   

A Leader is a type of Annotation_curve. A Leader directs a dimension, a note, or a symbol to the intended place on an element of geometry or annotation.

NOTE    The concept of Leader is incompletely modeled in the ARM for some use cases. Complete specification can be obtained in the definition of the MIM entities annotation_to_annotation_leader_line, annotation_to_model_leader_line, and auxiliary_leader_line.

EXPRESS specification:

*)
ENTITY Leader
  SUBTYPE OF (Annotation_curve);
END_ENTITY;
(*

4.3.9 Leader_directed_callout   

EXPRESS specification:

*)
ENTITY Leader_directed_callout
  SUBTYPE OF (Draughting_callout);
  leader : Leader;
WHERE
  WR1: leader IN SELF\Draughting_callout.contents;
END_ENTITY;
(*

Attribute definitions:

leader: the leader curve that directs the draughting callout.

Formal propositions:

WR1: The leader must be in the list of items defined in attribute contents.

4.3.10 Projection_curve   

EXPRESS specification:

*)
ENTITY Projection_curve
  SUBTYPE OF (Annotation_curve);
END_ENTITY;
(*

4.3.11 Projection_directed_callout   

EXPRESS specification:

*)
ENTITY Projection_directed_callout
  SUBTYPE OF (Draughting_callout);
  projection_curve : Projection_curve;
WHERE
  WR1: projection_curve IN SELF\Draughting_callout.contents;
END_ENTITY;
(*

Attribute definitions:

projection_curve: the projection curve that directs the draughting callout.

Formal propositions:

WR1: The projection_curve must be in the list of items defined in attribute contents.

4.4 ARM subtype constraint definition

This subclause specifies the ARM subtype constraint for this module. The subtype constraint places a constraint on the possible super-type / subtype instantiations. The ARM subtype constraint and definition is specified below.

4.4.1 annotation_curve_subtypes   

The annotation_curve_subtypes constraint specifies a constraint that applies to instances of Annotation_curve and enforces the rule that its subtypes Leader, Projection_curve and Dimension_curve are exclusive.

EXPRESS specification:

*)
SUBTYPE_CONSTRAINT annotation_curve_subtypes FOR Annotation_curve;
  (ONEOF (Leader,
          Projection_curve,
          Dimension_curve)
  ANDOR Generic_annotation_curve);
END_SUBTYPE_CONSTRAINT;
(*

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