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Application module:
Advanced boundary representation |
ISO/TS 10303-1514:2018-11(E)
© ISO
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This clause specifies the information requirements for the
Advanced boundary representation
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
Advanced_boundary_representation_arm
schema and identifies the necessary external references.
EXPRESS specification:
*)
SCHEMA Advanced_boundary_representation_arm;
(*
The following EXPRESS interface statements specify the elements
imported from the ARMs of other application modules.
EXPRESS specification:
*)
USE FROM
Topologically_bounded_surface_arm;
--
ISO/TS 10303-1511
USE FROM
Solid_model_arm;
--
ISO/TS 10303-1793
(*
NOTE 1
The schemas referenced above are specified in the following
part of ISO 10303:
| Topologically_bounded_surface_arm |
ISO/TS 10303-1511 |
| Solid_model_arm |
ISO/TS 10303-1793 |
NOTE 2
See Annex C,
Figures
C.1and C.2
for a graphical representation of this schema.
This subclause specifies the ARM type
for this application module. The ARM type and
definition is specified below.
A SELECT type defining the types of element that are to be used in the definition of an Advanced_brep_shape_representation.
EXPRESS specification:
*)
TYPE
advanced_brep_shape_representation_item =
SELECT
(Axis_placement_3d,
Geometric_placement_operation,
Manifold_solid_brep);
END_TYPE;
(*
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.
An Advanced_brep_shape_representation is a type of
Geometric_model
in which the representation items are specializations of the
Manifold_solid_brep
entity.
These specializations differ from the more general B-rep in that they shall only use explicit geometric forms for their face
and edge geometry.
The face geometry is restricted to elementary surfaces, swept surfaces or B-spline surfaces.
NOTE 1
This entity is incompletely modelled in the ARM. Complete specification
can be obtained in the definition of the corresponding MIM entity.
The MIM entity contains additional constraints on the usage of
mapped_items
in this entity.
To ensure that an appropriate manifold solid B-rep is included in the representation.
EXPRESS specification:
*)
ENTITY Advanced_brep_shape_representation
SUBTYPE OF (Geometric_model);
SELF\Representation.items : SET[1:?] OF advanced_brep_shape_representation_item;
WHERE
WR1: SIZEOF(QUERY ( msb <* QUERY ( it <* SELF.items |
('ADVANCED_BOUNDARY_REPRESENTATION_ARM.MANIFOLD_SOLID_BREP' IN TYPEOF(it)) ) |
( NOT (SIZEOF(QUERY ( csh <* collect_shells(msb) |
(NOT (SIZEOF(QUERY ( fcs <* csh\
connected_face_set.connected_faces | (NOT (
'ADVANCED_BOUNDARY_REPRESENTATION_ARM.ADVANCED_FACE' IN TYPEOF(fcs))) )) = 0)) ))
= 0)) )) = 0;
END_ENTITY;
(*
Attribute definitions:
items:
a set of
advanced_brep_shape_representation_items
that the Advanced_brep_shape_representation is a collection of. Each item is either a Manifold_solid_brep, an Axis_placement_3d,
or a Geometric_placement_operation.
NOTE 2
When a Geometric_placement_operation is included there are
rules in the corresponding MIM entity to ensure that it is a mapping of an Advanced_brep_shape_representation.
Formal propositions:
WR1:
for each Manifold_solid_brep
in the items set each face shall be an Advanced_face.
This ensures that the geometry and topology of the B-rep are fully defined.
A Closed_shell is a type of
Connected_face_set that encloses a finite volume of space.
EXPRESS specification:
*)
ENTITY Closed_shell
SUBTYPE OF (Connected_face_set);
END_ENTITY;
(*
A Manifold_solid_brep is a type of
Solid_model that may contain multiple elements, faces or surfaces organized into shells.
EXPRESS specification:
*)
ENTITY Manifold_solid_brep
SUBTYPE OF (Solid_model);
outer : Closed_shell;
voids :
OPTIONAL
SET[1:?] OF Oriented_closed_shell;
WHERE
WR1: (NOT EXISTS(voids)) OR (SIZEOF(QUERY ( ocs <* SELF.voids |
( NOT (ocs.orientation = FALSE)))) = 0);
END_ENTITY;
(*
Attribute definitions:
outer:
specifies the role of the
Closed_shell
as outer shell of the Manifold_solid_brep.
voids:
specifies the
Oriented_closed_shell
enclosing the interior voids of the Manifold_solid_brep.
The value of this attribute need not be specified.
Formal propositions:
WR1:
Either there shall be no voids attribute, or each Oriented_closed_shell in this set shall have orientation = FALSE.
An Oriented_closed_shell is a type of Closed_shell constructed by referencing another Closed_shell and contains a BOOLEAN
orientation flag to indicate whether or not the orientation of the constructed Closed_shell agrees with, or is opposite to, the
orientation of the original Closed_shell.
EXPRESS specification:
*)
ENTITY Oriented_closed_shell
SUBTYPE OF (Closed_shell);
shell : Closed_shell;
orientation : BOOLEAN;
WHERE
WR1: NOT ('ADVANCED_BOUNDARY_REPRESENTATION_ARM.ORIENTED_CLOSED_SHELL'
IN TYPEOF (SELF.shell));
END_ENTITY;
(*
Attribute definitions:
shell:
the Closed_shell which defines the faces of the Oriented_closed_shell.
NOTE
This entity is not fully defined in the ARM; the corresponding MIM object has an additional attribute which derives the set
of correctly oriented faces for the oriented closed shell from those of shell.
orientation:
the relationship between the orientation of the Oriented_closed_shell being defined and
the shell referenced.
Formal propositions:
WR1:
The type of shell shall not be Oriented_closed_shell.
This subclause specifies the ARM function for
this module. The ARM function and definition is
specified below.
The collect_shells function collects all the shells used in the definition of a Manifold_solid_brep into a set.
EXPRESS specification:
*)
FUNCTION collect_shells (brep : Manifold_solid_brep) : SET[1:?] OF Closed_shell;
LOCAL
return_set: SET[1:?] OF closed_shell := [brep.outer];
END_LOCAL;
IF SIZEOF(brep.voids) >= 1
THEN
return_set := return_set + brep.voids;
END_IF;
RETURN(return_set);
END_FUNCTION;
(*
Argument definitions:
brep:
(input) the Manifold_solid_brep for which it is required to collect the shells.
*)
END_SCHEMA; -- Advanced_boundary_representation_arm
(*
© ISO 2018 — All rights reserved
