ISO 10303-521:2003

Industrial automation systems and integration — Product data representation and exchange — Part 521: Application interpreted construct: Manifold subsurface

ISO 10303-521:2003 specifies the interpretation of the integrated resources to satisfy the requirement for the definition of a shape representation containing open shells defined as connected face sub sets. The domain of each connected face sub set is part of the domain of another open, or closed shell. Within the connected face sub set individual faces or edges may be identified as being subfaces, or subedges. The following are within the scope of ISO 10303-521:2003: 3D geometry; advanced faces; connected face sub sets; mappings and geometric transformations; open shells; relationships between domains of topological objects; subedges; subfaces; unbounded geometry with associated topological boundaries; use of topology to bound geometric entities. The following are outside the scope of ISO 10303-521:2003: 2D geometry other than for the definition of a pcurve in the parameter space of a surface; boundary representation solid models; bounded curves other than polylines and B-spline curves; bounded surfaces other than B-spline surfaces; non-manifold geometry; offset curves and surfaces; unbounded geometry without topological boundaries.

Systèmes d'automatisation industrielle et intégration — Représentation et échange de données de produits — Partie 521: Construction interprétée d'application: Surface complexe à topologie non eulérienne

General Information

• Status: Withdrawn
• Publication Date: 16-Mar-2003
• Withdrawal Date: 16-Mar-2003
• ICS: 25.040.40 - Industrial process measurement and control
• Technical Committee: ISO/TC 184/SC 4 - Industrial data
• Drafting Committee: ISO/TC 184/SC 4/WG 12 - STEP product modelling and resources
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 14-Dec-2011

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10303-521
First edition
2003-03-01

Industrial automation systems
and integration — Product data
representation and exchange —
Part 521:
Application interpreted construct:
Manifold subsurface
Systèmes d'automatisation industrielle et intégration — Représentation
et échange de données de produits —
Partie 521: Construction interprétée d'application: Surface complexe à
topologie non eulérienne




Reference number
ISO 10303-521:2003(E)
©
ISO 2003

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ISO 10303-521:2003(E)
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ISO 10303-521:2003(E)
Contents Page
1 Scope . . . . . 1
2 Normativereferences . . . . 2
3 Terms,definitionsandabbreviations . . . . 2
3.1 Terms defined in ISO 10303-1 . . . . 3
3.2 Terms defined in ISO 10303-42 . . . 3
3.3 Terms defined in ISO 10303-202 . . . 4
3.4 Terms defined in ISO 10303-511 . . . 4
3.5 Otherdefinitions . . . . 4
3.6 Abbreviations. . . . 4
4 EXPRESSshortlisting . . . . 5
4.1 Fundamental concepts and assumptions . . . 6
4.2 aic manifold subsurface schema entity definition:
manifold subsurface shaperepresentation . . . 8
4.3 aic manifold subsurface schema function definition:
advanced faceproperties . . . . 12
Annex A (normative) Short names of entities. . . 13
AnnexB(normative) Informationobjectregistration . . . 14
B.1 Documentidentification . . . . 14
B.2 Schemaidentification. . . . 14
AnnexC(informative) Computer-interpretablelistings . . . 15
AnnexD(informative) EXPRESS-Gdiagrams . . . 16
AnnexE(informative) AICusageexample . . . 26
Bibliography . . . . . 32
Index . . . . . 33
Figures
Figure D.1 aic manifoldsubsurfaceEXPRESS-Gdiagrampage1of9 . . 17
Figure D.2 aic manifoldsubsurfaceEXPRESS-Gdiagrampage2of9 . . 18
Figure D.3 aic manifoldsubsurfaceEXPRESS-Gdiagrampage3of9 . . 19
Figure D.4 aic manifoldsubsurfaceEXPRESS-Gdiagrampage4of9 . . 20
Figure D.5 aic manifoldsubsurfaceEXPRESS-Gdiagrampage5of9 . . 21
Figure D.6 aic manifoldsubsurfaceEXPRESS-Gdiagrampage6of9 . . 22
Figure D.7 aic manifoldsubsurfaceEXPRESS-Gdiagrampage7of9 . . 23
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ISO 10303-521:2003(E)
Figure D.8 aic manifoldsubsurfaceEXPRESS-Gdiagrampage8of9 . . 24
Figure D.9 aic manifoldsubsurfaceEXPRESS-Gdiagrampage9of9 . . 25
Figure E.1 Manifold subsurface shape representation - faces and subfaces . . 31
Tables
Table A.1 Short names of entities . . . . . . 13
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ISO 10303-521:2003(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical com-
mittee has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates
closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical stan-
dardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Stan-
dards adopted by the technical committees are circulated to the member bodies for voting. Publication
as an International Standard requires approval by at least 75% of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 10303-521 was prepared by Technical Committee ISO/TC 184/SC 4. Industrial automation systems
and integration, Subcommittee SC 4, Industrial data.
This International Standard is organised as a series of parts, each published separately. The structure of
this International Standard is decribed in ISO 10303-1.
Each part of this International Standard is a member of one of the following series: decription meth-
ods, implementation methods, conformance testing methodology and framework, integrated generic
resources, integrated application resources, application protocols, abstract test suites, application inter-
preted constructs, and application modules. This part is a member of the application interpreted construct
series.
A complete list of parts of ISO 10303 is available from Internet:

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ISO 10303-521:2003(E)
Introduction
ISO 10303 is an International Standard for the computer-interpretable representation and exchange of
product data. The objective is to provide a neutral mechanism capable of describing products throughout
their life cycle. This mechanism is suitable not only for neutral file exchange, but also as a basis for
implementing and sharing product databases and as a basis for archiving.
This part of ISO 10303 is a member of the application interpreted construct series. An application
interpreted construct (AIC) provides a logical grouping of interpreted constructs that supports a specific
functionality for the usage of product data across multiple application contexts. An interpreted construct
is a common interpretation of the integrated resources that supports shared information requirements
among application protocols.
This document specifies the application interpreted construct for manifold subsurface. This provides the
definition of a shape representation containing open shells, each of which is identified as being part of
another open or closed shell. The shells are defined using faces with explicit topology and fully defined
geometry. The faces of the shells defined in this AIC either use the advanced face definition from ISO
10303-511, or have similar properties.
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INTERNATIONAL STANDARD ISO 10303-521:2003(E)
Industrial automation systems and integration —
Product data representation and exchange —
Part 521:
Application interpreted construct:
Manifold subsurface
1Scope
This part of ISO 10303 specifies the interpretation of the integrated resources to satisfy the requirement
for the definition of a shape representation containing open shells defined as connected face sub sets.
The domain of each connected face sub set is part of the domain of another open, or closed shell. Within
the connected face sub set individual faces or edges may be identified as being subfaces, or subedges.
The following are within the scope of this part of ISO 10303:
— 3D geometry;
— advanced faces;
— connected face sub sets;
— mappings and geometric transformations;
— open shells;
— relationships between domains of topological objects;
— subedges;
— subfaces;
— unbounded geometry with associated topological boundaries;
— use of topology to bound geometric entities.
The following are outside the scope of this part of ISO 10303:
— 2D geometry other than for the definition of a pcurve in the parameter space of a surface;
— boundary representation solid models;
— bounded curves other than polylines and B-spline curves;
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ISO 10303-521:2003(E)
— bounded surfaces other than B-spline surfaces;
— non-manifold geometry;
— offset curves and surfaces;
— unbounded geometry without topological boundaries.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/IEC 8824-1: 1998, Information technology- Abstract syntax notation one (ASN.1) Part 1: Speci-

fication of basic notation
ISO 10303-1: 1994, Industrial automation systems and integration - Product data representation and
exchange- Part 1: Overview and fundamental principles
ISO 10303-11: 1994, Industrial automation systems and integration - Product data representation and
exchange- Part 11: Description methods: The EXPRESS language reference manual
ISO 10303-41: 2000, Industrial automation systems and integration - Product data representation and
exchange- Part 41: Integrated generic resource: Fundamentals of product description and support
ISO 10303-42: 2000, Industrial automation systems and integration - Product data representation and
exchange- Part 42: Integrated generic resource: Geometric and topological representation
ISO 10303-43: 2000, Industrial automation systems and integration - Product data representation and
exchange- Part 43: Integrated generic resource: Representation structures
ISO 10303-202: 1995, Industrial automation systems and integration - Product data representation and
exchange- Part 202: Application protocol: Associative draughting
ISO 10303-511: 2001, Industrial automation systems and integration - Product data representation and
exchange- Part 511: Application interpreted construct: Topologically bounded surface
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ISO 10303-521:2003(E)
3 Terms, definitions and abbreviations
3.1 Terms defined in ISO 10303-1
For the purposes of this part of ISO 10303, the following terms defined in ISO 10303-1 apply.
— application;
— application context;
— application protocol;
— implementation method;
— integrated resource;
— interpretation;
— product data.
3.2 Terms defined in ISO 10303-42
For the purposes of this part of ISO 10303, the following terms defined in ISO 10303-42 apply.
— arcwise connected;
— axi-symmetric;
— boundary;
— bounds;
— coordinate space;
— curve;
— domain;
— extent;
— open curve;
— orientable;
— surface;
— topological sense.
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ISO 10303-521:2003(E)
3.3 Terms defined in ISO 10303-202
For the purposes of this part of ISO 10303, the following term defined in ISO 10303-202 applies.
— application interpreted construct.
3.4 Terms defined in ISO 10303-511
For the purposes of this part of ISO 10303, the following term defined in ISO 10303-511 applies.
— advanced face.
3.5 Other definitions
3.5.1
Connected face subset
set of arcwise connected faces whose domain is a portion of the domain of an existing connected face set
NOTE 1 In this part of ISO 10303 a connected face subset is also required to be of type open shell.
3.5.2
manifold subsurface shape representation
shape representation containing connected face sub sets in the form of open shells
NOTE 1 Each open shell has a domain that is part of the domain of another connected face set. The faces of the
connected face sub set may be defined as subfaces.
3.5.3
subedge
edge whose domain is a connected portion of the domain of another edge
3.5.4
subface
face whose domain is a connected portion of the domain of another face
NOTE 1 In this part of ISO 10303 a subface has a domain which is part of the domain of an advanced face.
3.6 Abbreviations
For the purposes of this part of ISO 10303, the following abbreviations apply.
AIC Application Interpreted Construct
AP Application Protocol
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ISO 10303-521:2003(E)
4 EXPRESS short listing
This clause specifies the EXPRESS schema that uses elements from the integrated resources and con-
tains the types, entity specializations, and functions that are specific to this part of ISO 10303.
NOTE 1 There may be subtypes and items of select lists that appear in the integrated resources that are not
imported into the AIC. Constructs are eliminated from the subtype tree or select list through the use of the implicit
interface rules of ISO 10303-11. References to eliminated constructs are outside the scope of the AIC. In some
cases, all items of the select list are eliminated. Because AICs are intended to be implemented in the context of an
application protocol, the items of the select list will be defined by the scope of the application protocol.
This application interpreted construct provides a consistent set of geometric and topological entities for
the definition of manifold subsurface shape representation. Faces may be advanced faces or subfaces
referencing an advanced face. Edges are required to be subedges, or, to have their geometry defined by
curves. The highest level entity in this AIC is manifold subsurface shape representation which is a
specialised type of shape representation (see ISO 10303-41). The rules on this entity ensure that the
topology and geometry are fully defined.
NOTE 2 This AIC uses all the entities and types from the topologicallybounded surface AIC (aic topologically -
bounded surface). ISO 10303-511 should be referred to in order to obtain the complete data set.
EXPRESS specification:
*)
SCHEMA aic_manifold_subsurface;
USE FROM aic_topologically_bounded_surface; -- ISO 10303-511
USE FROM geometry_schema -- ISO 10303-42
(cartesian_transformation_operator_3d);
USE FROM topology_schema -- ISO 10303-42
(closed_shell,
connected_face_set,
connected_face_sub_set,
face,
open_shell,
subedge,
subface);
USE FROM representation_schema(mapped_item); -- ISO 10303-43
USE FROM product_property_representation_schema -- ISO 10303-41
(shape_representation);
(*
NOTE 3 The schemas referenced above can be found in the following parts of ISO 10303:
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ISO 10303-521:2003(E)
geometry schema ISO 10303-42: 2000
topology schema ISO 10303-42: 2000
representation schema ISO 10303-43
product property representation schema ISO 10303-41
aic topologically bounded surface ISO 10303-511
4.1 Fundamental concepts and assumptions
1)
The following entities are intended to be independently instantiated in the application protocol schemas
that use this AIC:
— advanced face [511];
— axis2 placement 2d [511];
— axis2 placement 3d [511];
— brep with voids;
— bezier curve [511];
— bezier surface [511];
— b spline curve with knots [511];
— b spline surface with knots [511];
— cartesian point [511];
— cartesian transformation operator 3d;
— circle [511];
— closed shell;
— conical surface [511];
— definitional representation [511];
— degenerate toroidal surface [511];
— connected face sub set;
— cylindrical surface [511];
1)
The entities marked [511] are defined in the aic topologically bounded surface
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ISO 10303-521:2003(E)
— direction [511];
— edge curve [511];
— edge loop [511];
— ellipse [511];
— face bound [511];
— face outer bound [511];
— geometric representation context [511];
— hyperbola [511];
— line [511];
— manifold subsurface shape representation;
— mapped item;
— open shell;
— parabola [511];
— parametric representation context [511];
— pcurve [511];
— plane [511];
— polyline [511];
— quasi uniform curve [511];
— quasi uniform surface [511];
— rational b spline curve [511];
— rational b spline surface [511];
— representation map;
— spherical surface [511];
— subedge;
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ISO 10303-521:2003(E)
— subface;
— surface of linear extrusion [511];
— surface of revolution [511];
— toroidal surface [511];
— uniform curve [511];
— uniform surface [511];
— vector [511];
— vertex loop [511];
— vertex point [511].
An application protocol that uses this AIC shall ensure that the shape representation entity is instanti-
ated as a manifold subsurface shape representation.
4.2 aic manifold subsurface schema entity definition:
manifold subsurface shape representation
The manifold subsurface shape representation is a type of shape representation in which the shape
of a product is represented by specialisations of connected face sub set entities.
Each connected face sub set isrequiredtobealsooftype open shell.
The facesof the connected face sub sets are required to be of type advanced face, or, to be of type
subface.
EXPRESS specification:
*)
ENTITY manifold_subsurface_shape_representation
SUBTYPE OF (shape_representation);
WHERE
WR1: SIZEOF (QUERY (it <* SELF.items |
NOT (SIZEOF ([’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’,
’AIC_MANIFOLD_SUBSURFACE.MAPPED_ITEM’,
’AIC_MANIFOLD_SUBSURFACE.AXIS2_PLACEMENT_3D’] *
TYPEOF(it)) = 1))) = 0;
WR2: SIZEOF (QUERY (it <* SELF.items |
SIZEOF([’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’,
’AIC_MANIFOLD_SUBSURFACE.MAPPED_ITEM’] * TYPEOF(it)) =1 )) > 0;
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ISO 10303-521:2003(E)
WR3: SIZEOF (QUERY (mi <* QUERY (it <* items |
’AIC_MANIFOLD_SUBSURFACE.MAPPED_ITEM’ IN TYPEOF(it)) |
NOT (’AIC_MANIFOLD_SUBSURFACE.MANIFOLD_SUBSURFACE_SHAPE_REPRESENTATION’ IN
TYPEOF(mi\mapped_item.mapping_source.
mapped_representation)))) = 0;
WR4: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’ IN TYPEOF(it)) |
NOT(’AIC_MANIFOLD_SUBSURFACE.OPEN_SHELL’ IN TYPEOF(cfss)))) = 0;
WR5: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’ IN TYPEOF(it)) |
NOT( ((’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’ IN
TYPEOF(cfss.parent_face_set)) AND
(SIZEOF (QUERY (fac <* cfss.parent_face_set.cfs_faces | NOT
advanced_face_properties(fac))) = 0)) OR
(SIZEOF (QUERY (fac <* cfss.parent_face_set.cfs_faces | NOT
(’AIC_MANIFOLD_SUBSURFACE.ADVANCED_FACE’ IN TYPEOF(fac)))) = 0)
)))=0;
WR6: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’ IN TYPEOF(it)) |
( SIZEOF (QUERY (fac <* cfss\connected_face_set.cfs_faces | NOT
advanced_face_properties(fac))) = 0))) = 0;
WR7: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’ IN TYPEOF(it)) |
NOT (SIZEOF (QUERY(fcs <* cfss\connected_face_set.cfs_faces |
(’AIC_MANIFOLD_SUBSURFACE.SUBFACE’ IN TYPEOF(fcs)) AND
NOT (SIZEOF(QUERY (elp_fbnds <* QUERY (bnds <* fcs.bounds |
’AIC_MANIFOLD_SUBSURFACE.EDGE_LOOP’ IN TYPEOF(bnds.bound)) |
NOT (SIZEOF (QUERY (oe <* elp_fbnds.bound\path.edge_list |
NOT((’AIC_MANIFOLD_SUBSURFACE.EDGE_CURVE’ IN
TYPEOF(oe.edge_element)) OR
(’AIC_MANIFOLD_SUBSURFACE.SUBEDGE’ IN
TYPEOF(oe.edge_element)) ))) = 0
)))=0
)))=0
))) = 0;
WR8: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUBSET’ IN TYPEOF(it)) |
NOT (SIZEOF (QUERY(fcs <* cfss\connected_face_set.cfs_faces |
(’AIC_MANIFOLD_SUBSURFACE.SUBFACE’ IN TYPEOF(fcs)) AND
NOT (SIZEOF(QUERY (elp_fbnds <* QUERY (bnds <* fcs.bounds |
’AIC_MANIFOLD_SUBSURFACE.EDGE_LOOP’ IN TYPEOF(bnds.bound)) |
NOT (SIZEOF (QUERY (oe <* elp_fbnds.bound\path.edge_list |
NOT((’AIC_MANIFOLD_SUBSURFACE.VERTEX_POINT’ IN TYPEOF(oe.edge_start))
AND (’AIC_MANIFOLD_SUBSURFACE.VERTEX_POINT’ IN
TYPEOF(oe.edge_end))
))) = 0
))) = 0
))) = 0
)))=0;
WR9: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’ IN TYPEOF(it)) |
NOT (SIZEOF (QUERY(fcs <* cfss\connected_face_set.cfs_faces |
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ISO 10303-521:2003(E)
( ’AIC_MANIFOLD_SUBSURFACE.SUBFACE’ IN TYPEOF(fcs)) AND
( NOT (SIZEOF(QUERY (bnds <* fcs.bounds |
NOT (SIZEOF ([’AIC_MANIFOLD_SUBSURFACE.EDGE_LOOP’,
’AIC_MANIFOLD_SUBSURFACE.VERTEX_LOOP’] *
TYPEOF(bnds.bound)) = 1 )
))=0)
)))=0
))) = 0;
WR10: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUB_SET’ IN TYPEOF(it)) |
NOT (SIZEOF (QUERY(fcs <* cfss\connected_face_set.cfs_faces |
( ’AIC_MANIFOLD_SUBSURFACE.SUBFACE’ IN TYPEOF(fcs)) AND
( NOT (SIZEOF(QUERY (elp_fbnds <* QUERY (bnds <* fcs.bounds |
’AIC_MANIFOLD_SUBSURFACE.EDGE_LOOP’ IN TYPEOF(bnds.bound)) |
NOT (SIZEOF (QUERY (oe <* elp_fbnds.bound\path.edge_list |
NOT (SIZEOF ([’AIC_MANIFOLD_SUBSURFACE.LINE’,
’AIC_MANIFOLD_SUBSURFACE.CONIC’,
’AIC_MANIFOLD_SUBSURFACE.POLYLINE’,
’AIC_MANIFOLD_SUBSURFACE.SURFACE_CURVE’,
’AIC_MANIFOLD_SUBSURFACE.B_SPLINE_CURVE’ ] *
TYPEOF(oe.edge_element\edge_curve.edge_geometry)) = 1 )
)) = 0
))) = 0
)))) = 0
)))=0;
WR11: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUBSET’ IN TYPEOF(it)) |
NOT (SIZEOF (QUERY(fcs <* cfss\connected_face_set.cfs_faces |
( ’AIC_MANIFOLD_SUBSURFACE.SUBFACE’ IN TYPEOF(fcs)) AND
(NOT (SIZEOF(QUERY (elp_fbnds <* QUERY (bnds <* fcs.bounds |
’AIC_MANIFOLD_SUBSURFACE.EDGE_LOOP’ IN TYPEOF(bnds.bound)) |
NOT (SIZEOF (QUERY (oe <* elp_fbnds.bound\path.edge_list |
(’AIC_MANIFOLD_SUBSURFACE.SURFACE_CURVE’ IN
TYPEOF(oe.edge_element\edge_curve.edge_geometry)) AND
(NOT ((SIZEOF (QUERY (sc_ag <*
oe.edge_element\edge_curve.edge_geometry\
surface_curve.associated_geometry |
NOT (’AIC_TOPOLOGICALLY_BOUNDED_SURFACE.PCURVE’ IN
TYPEOF(sc_ag)))) = 0)))
)) = 0
))) = 0
)))) = 0
)))=0;
WR12: SIZEOF (QUERY (cfss <* QUERY (it <* SELF.items |
’AIC_MANIFOLD_SUBSURFACE.CONNECTED_FACE_SUBSET’ IN TYPEOF(it)) |
NOT (SIZEOF (QUERY(fcs <* cfss\connected_face_set.cfs_faces |
( ’AIC_MANIFOLD_SUBSURFACE.SUBFACE’ IN TYPEOF(fcs)) AND
(NOT (SIZEOF(QUERY (elp_fbnds <* QUERY (bnds <* fcs.bounds |
’AIC_MANIFOLD_SUBSURFACE.EDGE_LOOP’ IN TYPEOF(bnds.bound)) |
NOT (SIZEOF (QUERY (oe <* elp_fbnds.bound\path.edge_list |
(’AIC_MANIFOLD_SUBSURFACE.POLYLINE’ IN
TYPEOF(oe.edge_element\edge_curve.edge_geometry)) AND
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ISO 10303-521:2003(E)
(NOT (SIZEOF (oe\oriented_edge.edge_element\
edge_curve.edge_geometry\polyline.points) >= 3))
)) = 0
))) = 0
)))) = 0
)))=0;
END_ENTITY;
(*
Formal propositions:
WR1: The items in a manifold subsurface shape representation shall be connected face sub sets,
mapped items, or axis2 placement 3ds.
WR2: At least one of the items shall be either a connected face sub set or a mapped item.
WR3: For any mapped item,the mapped representation of its mapping source shall be a manifold -
subsurface shape representation.
WR4: Any instance of connected face sub set in the items set shall be of type connected face sub set
AND open shell.
WR5: For any instance of connected face sub set the facesof the parent face set shall be of type
advanced face or the parent face set shall be an instance of connected face sub set whose faces are
related to advanced faces.
NOTE 1 The parent face set may be one of the subtypes, open shell,or closed shell of connected face set.
WR6: For any instance of connected face subset each face of the cfs faces attribute shall be of type
advanced face or of type subface and, directly or indirectly, reference an advanced face.
NOTE 2 This property is verified by the advanced face properties function.
WR7: For any instance of subface in the cfs faces of a connected face sub set instance the bounding
edges shall be of type subedge or of type edge curve.
WR8: For any instance of subface in the cfs faces of a connected face sub set instance all vertices
used in the face definition shall be of type vertex point.
WR9: The bounds of any subface in the cfs faces of a connected face sub set instance shall be of type
edge loop, or, of type vertex loop.
WR10: The types of curve used to define the geometry of an edge curve used in the definition of a
subface shall be restricted to lines, conics, polylines, surface curvesorb spline curves.
WR11: If a surface curve is used as part of a face bound of a subface the associated geometry at-
tribute shall reference a pcurve.
WR12: If a polyline is used as part of a face bound of a subface it shall contain at least 3 points.
NOTE 3 Rules WR8 to WR13 ensure that the definition of the bounds of a subface are consistent with those of
an advanced face.
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ISO 10303-521:2003(E)
4.3 aic manifold subsurface schema function definition:
advanced face properties
The advanced face properties function checks the properties of a face to determine if it is of type
advanced face, or, if it is a subface directly, or indirectly, referencing an advanced face as parent face.
This check is carried out recursively and a TRUE result is returned if the face either is an advanced face,
or, via the parent face attribute of a subface references an advanced face. In all other cases a FALSE
result is returned.
EXPRESS specification:
*)
FUNCTION advanced_face_properties (testface : face) : BOOLEAN;
(* return TRUE if testface is of type advanced_face *)
IF ’AIC_MANIFOLD_SUBSURFACE.ADVANCED_FACE’ IN TYPEOF(testface) THEN
RETURN (TRUE);
END_IF;
(* if testface is a subface recursively test the parent_face,
return FALSE for all other types of face *)
IF (’AIC_MANIFOLD_SUBSURFACE.SUBFACE’ IN TYPEOF(testface)) THEN
RETURN(advanced_face_properties(testface.parent_face));
ELSE RETURN (FALSE);
END_IF;
END_FUNCTION;
(*
Argument definitions:
testface: (input) The face which is to be tested for advanced face properties.
result: (output) A BOOLEAN variable which is TRUE if testface is of type advanced face.orisof
type subface and references an advanced face.
EXPRESS specification:
*)
END_SCHEMA; -- end AIC_MANIFOLD_SUBSURFACE SCHEMA
(*
12c ISO 2003 — All rights reserved

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ISO 10303-521:2003(E)
Annex A
(normative)
Short names of entities
Table A.1 provides the short names of entities specified in the EXPRESS listing of this part of ISO 10303.
Requirements on the use of the short names are found in the implementation methods included in
ISO 10303.
Table A.1 – Short names of entities
Entity name Short name
MANIFOLD SUBSURFACE SHAPE REPRESENTATION MSSO
c ISO 2003— All rights reserved 13

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ISO 10303-521:2003(E)
Annex B
(normative)
Information object registration
B.1 Document identification
To provide for unambiguous identification of an information object in an open system, the object identi-
fier
f iso standard 10303 part(521) version(1) g
is assigned to this part of ISO 10303. The meaning of this value is defined in ISO/IEC 8824-1, and is
described in ISO 10303-1.
B.2 Schema identification
To provide for unambiguous identification of the aic manifold subsurface in an open information system,
the object identifier
f iso standard 10303 part(521) version(1) schema(1) aic-manifold-subsurface(1) g
is assigned to the aic manifold subsurface schema (see 4). The meaning of this value is defined in
ISO/IEC 8824-1, and is described in ISO 10303-1.
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ISO 10303-521:2003(E)
Annex C
(informative)
Computer-interpretable listings
This annex provides a listing of the EXPRESS entity names and corresponding short names as speci-
fied in this Part of ISO 10303 without comments or other explanatory text. This annex is available in
computer-interpretable form and can be found at the following URLs:
Short names:
EXPRESS:
If there is difficulty accessing these sites contact ISO Central Secretariat or contact the ISO TC 184/SC4
Secretariat directly at: [e-mail].
NOTE – The information provided in computer-interpretable form at the above URLs is informative. The infor-
mation that is contained in the body of this part of ISO 10303 is normative.
c ISO 2003— All rights reserved 15

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