Model Space

Overview

Provides the information concerning a space within a building model.
A space is defined as representing an area or volume bounded actually or theoretically. In IFC, spaces are further defined as areas or volumes that provide for certain functions within a building. However, a space may equally be defined as providing for functions outside a building.
The information presented in this functional part is sufficient for the concept of modelling spaces within the exchange of a basic building model. This information includes:

Specification of space (room) name
This should be the unique name (or space number) for the space (equivalent to the space number identifier from a plan). Note that international standards exist for room naming and it is recommended that these be used if possible
Specification of space (room) description
This can be used for any further qualifying information about a space
Specification of an extended (long) name for the space (room).
This can be used to capture the full name of the space. It is often used in addition to the name.
For instance, if a number is assigned to the room, then the descriptive name is exchanged as a Long Name
Specification of the space type
This usually identifies the functional category of the space (e.g. bedroom, kitchen, office etc.)
Dimensional information about the space
This may be given to enable the creation of a shape representation if the space shape cannot otherwise be found from the building elements (wall, roof etc.) bounding it. This would be particularly the case during early stages of design where the space needs to be established but the building itself is not broken down into parts. Overall space shape for external spaces should also be provided for communication with geographic information systems. The form of shape representation used for a shape may differ at various stages of a building project and these are specifically identified within exchange requirements. Particular forms of shape representation may include
- 2D footprint representation with additional height information given as a quantity
- 3D body representation using swept solids
- 3D body representation using clipping of solids
Specification of whether the space is a complex of several spaces, an elemental (single) space or a part of a space.
- Where the space is a 'complex', identification of the elemental spaces that are nested into the complex.
- Where the space is a 'part', identification of the space into which the part is nested
- It should be noted that the 'part' breakdown of a space may give rise to overlapping shapes. Therefore, the overall shape of a space should not be derived by adding together the shapes of parts.
The level of flooring of the space relative to the reference elevation of the building
This should be used where the ground surface is sloping or if there are several levels within the space.
Identification of whether the space is internal or external
Mandatory common properties of a space required to identify:
- Reference to the type of space from a defined list of types for the project.
- Occupancy type from classifications given in the relevant local code and number of occupants anticipated. Occupancies may be given according to the form of activity of the occupant within the space.
- Indication of accessibility to a space for the public and disabled persons.

Results

Model of space occurrence(s) including shape representation and other basic information

Description	Entity/Pset/Functional Part	MAN	REC	OPT
Specify principal space attributes For the present, a space is directly specified as an occurrence within IFC. It does not have a defining type entity.
Set the global unique identifier	IfcSpace.GlobalId::IfcGloballyUniqueId
Apply the owner history	IfcSpace.OwnerHistory::fp_apply_owner_history
Specify the name of the space Although identified as an optional attribute within IFC, it is strongly recommended that the name of a space should be asserted. It is recommended that international or local standards for space naming are applied.	IfcSpace.Name::IfcLabel
Specify a description for the space The description of a space should be asserted if further information is required or if the naming provisions for the space provided by the schema are not sufficient for local naming purposes.	IfcSpace.Description::IfcText
Specify an extended name for the space Although identified as an optional attribute within IFC, it is strongly recommended that the long name of a space should be asserted. It is recommended that international or local standards for space naming are applied. Additionally, it is probable that classified lists of long names for spaces will exist for local usage (e.g. for local building codes) and it is strongly recommended that these are applied.	IfcSpace.LongName::IfcLabel
Specify the type (functional category) of the space Although IFC does not specify the 'type' of a space through a type definition entity as is the case with most other element subtypes, it does enable the type to be specified through the ObjectType attribute. It is strongly recommended that this attribute is asserted so that 'type' common data specified in property sets can be appropriately defined.	IfcSpace.ObjectType::IfcLabel
Set the flooring level within the space Use the average value for the flooring elevation where the floor is sloped or at multiple levels.	IfcSpace.ElevationWithFlooring::IfcLengthMeasure
Identify whether the space is internal or external This value must be asserted to identify the location of the space.	IfcSpace.InteriorOrExteriorSpace ? IfcInternalOrExternalEnum
For spaces that are to have one or more defined shape representations. Note that the provision of a (or several) shape representation for a space is not always necessary. This is particularly the case at early design stage where it is likely that space requirements are known but that no technical solution has been established. If a space is to have a shape representation, then the following must be asserted;
Establish the placement of the origin point of each space representation	IfcSpace.ObjectPlacement::fp_place_object
Define each shape representation of the space to be used	IfcSpce.Representation::fp_represent_product
For spaces that are to participate in a composition Note that spaces may be defined as being parts of other spaces or as a complex that configures several other spaces. Where a space is part of or configures other space(s), then the following must be asserted:
Set the composition type of the space occurrence (complex, element or part)	IfcSpace.CompositionType::IfcElementCompositionEnum
If the composition type of the space is a 'complex', identify the elemental space(s) that form part of the complex	fp_nest[space]
If the composition type of the space is a 'part', identify the elemental space of which it forms a part	fp_nest[space]
Identify elements in the space
Any elements that are to be contained within the space should be identified	fp_contains_in_spatial_structure[ space, Unknown macro: {elements} ]
Set required values in Pset_SpaceCommon
Reference type of space from the list defined for the project	Pset_SpaceCommon.Reference
Occupancy type (usually defined according to national, local or organisation space classification	Pset_SpaceCommon.OccupancyType
Intended maximum number of occupants for the designed usage of the space.	Pset_SpaceCommon.OccupancyNumber
Define the property set for the window occurrence	fp_define_by_properties
Set additional quantities as deemed appropriate	fp_apply_quantity

IFC Entities Required

IfcElement
IfcObject
IfcProduct
IfcRoot
IfcSpace
IfcSpatialStructureElement

IFC Datatypes Required

IfcElementCompositionEnum
IfcGloballyUniqueId
IfcInternalOrExternalEnum
IfcLabel
IfcLengthMeasure
IfcText

IFC Functions Required

-

IFC Property Sets Required

Pset_SpaceCommon

IDM Functional Parts Required

fp_address
fp_aggregates
fp_apply_owner_history
fp_apply_quantity
fp_contains_in_spatial_structure
fp_define_by_properties
fp_place_object
fp_represent_product

EXPRESS Schema

SCHEMA FP_MODEL_SPACE;

  TYPE IfcGloballyUniqueId = STRING (22) FIXED;
  END_TYPE;

  TYPE IfcLabel = STRING;
  END_TYPE;

  TYPE IfcLengthMeasure = REAL;
  END_TYPE;

  TYPE IfcText = STRING;
  END_TYPE;

  TYPE IfcElementCompositionEnum = ENUMERATION OF
    (COMPLEX,
     ELEMENT,
     PARTIAL);
  END_TYPE;

  TYPE IfcInternalOrExternalEnum = ENUMERATION OF
    (INTERNAL,
     EXTERNAL,
     NOTDEFINED);
  END_TYPE;

  ENTITY IfcProduct
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcObject);
      ObjectPlacement : OPTIONAL fp_place_object;
      Representation  : OPTIONAL fp_represent_product;
    WHERE
      WR1 : (EXISTS(Representation) AND EXISTS(ObjectPlacement))
            OR (EXISTS(Representation) AND 
            (NOT('IFC2X2_FINAL.IFCPRODUCTDEFINITIONSHAPE' IN TYPEOF(Representation))))
            OR (NOT(EXISTS(Representation)));
  END_ENTITY;

  ENTITY IfcObject
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcRoot);
      ObjectType : OPTIONAL IfcLabel;
    WHERE
      WR1 : SIZEOF(QUERY(temp <* IsDefinedBy | 'IFC2X2_FINAL.IFCRELDEFINESBYTYPE' IN TYPEOF(temp))) <= 1;
  END_ENTITY;

  ENTITY IfcRoot
    ABSTRACT SUPERTYPE;
      GlobalId     : IfcGloballyUniqueId;
      Name         : OPTIONAL IfcLabel;
      Description  : OPTIONAL IfcText;
      OwnerHistory : fp_apply_owner_history;
    UNIQUE
      UR1 : GlobalId;
  END_ENTITY;

  ENTITY IfcSpatialStructureElement
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcProduct);
      LongName        : OPTIONAL IfcLabel;
      CompositionType : IfcElementCompositionEnum;
    WHERE
      WR41 : (HIINDEX(SELF\IfcObject.Decomposes) = 1) 
             AND
             ('IFC2X2_FINAL.IFCRELAGGREGATES' IN TYPEOF(SELF\IfcObject.Decomposes[1])) 
             AND
             (('IFC2X2_FINAL.IFCPROJECT' IN TYPEOF (SELF\IfcObject.Decomposes[1].RelatingObject)) OR
             ('IFC2X2_FINAL.IFCSPATIALSTRUCTUREELEMENT' IN TYPEOF (SELF\IfcObject.Decomposes[1].RelatingObject))
             );
  END_ENTITY;

  ENTITY IfcSpace
    SUBTYPE OF(IfcSpatialStructureElement);
      InteriorOrExteriorspace : IfcInternalOrExternalEnum;
      ElevationWithFlooring   : OPTIONAL IfcLengthMeasure;
  END_ENTITY;

  ENTITY fp_apply_owner_history;
  END_ENTITY;

  ENTITY fp_aggregates;
  END_ENTITY;

  ENTITY fp_apply_quantity;
  END_ENTITY;

  ENTITY fp_contains_in_spatial_structure;
  END_ENTITY;

  ENTITY fp_define_by_properties;
  END_ENTITY;

  ENTITY fp_place_object;
  END_ENTITY;

  ENTITY fp_represent_product;
  END_ENTITY;

END_SCHEMA;

Examples of Modeling Spaces

Example 1: Modeling a general space

In this example, a bedroom space is considered. The bedroom is defined as being a type of living area whose reference is defined as 'bedroom' within a common space property set and whose occupancy type is set to 'sleeping'. The space name is set to W-001 which is used for local identification and it has a long name of 'master bedroom' which is how it is considered in German naming practice (shown in the included space as 'Elternschlafzimmer'). The space is considered to be a whole room and therefore its composition type is set to being an element. It is an internal space which is located at the same level as the building datum which is referred to as an elevation of 0.0.
Some additional properties are defined for the space including the fact that it is not publicly accessible (whilst this might be obvious for a bedroom, it does need to be identified as a property) but it is handicap accessible meaning that persons normally using a wheelchair would be able to use the space. The space is considered to be naturally ventilated at a rate of 2 air changes per hour. The space is not concealed and it has a net planned area of 58.29 square metres; the gross planned area is not asserted.

#2=IFCOWNERHISTORY(...);

/* defining the space */
#901=IFCSPACE('abcdefghijklmnopqrst901',#2,'W-001',$,'Living Area',#1284,#1300,'Master Bedroom',.ELEMENT.,.INTERNAL.,0.);

/* relating the space and the property set */
#911=IFCRELDEFINESBYPROPERTIES('abcdefghijklmnopqrst911',#2,$,$,(#901),#921);

/* definition of occurrence property set */
#921=IFCPROPERTYSET('abcdefghijklmnopqrst921',#2,'Pset_SpaceCommon',$,(#931,#932,#933,#934,#935,#936,#937,#938,#939,#940,#941));

/* definition of common properties for a space */
/* note that the optional values given in #938 and #940 relate to IFC 2x3 */
/* - a value must be asserted for prior IFC releases - */
#931=IFCPROPERTYSINGLEVALUE('Reference',$,'Bedroom',$);
#932=IFCPROPERTYSINGLEVALUE('OccupancyType',$,'Sleeping',$);
#933=IFCPROPERTYSINGLEVALUE('OccupancyNumber',$,2,$);
#934=IFCPROPERTYSINGLEVALUE('PubliclyAccessible',$,.FALSE.,$);
#935=IFCPROPERTYSINGLEVALUE('HandicapAccessible',$,.TRUE.,$);
#936=IFCPROPERTYSINGLEVALUE('NaturalVentilation',$,.TRUE.,$);
#937=IFCPROPERTYSINGLEVALUE('NaturalVentilationRate',$,2,$);
#938=IFCPROPERTYSINGLEVALUE('MechanicalVentilationRate',$,$,$);
#939=IFCPROPERTYSINGLEVALUE('Concealed',$,.FALSE.,$);
#940=IFCPROPERTYSINGLEVALUE('GrossPlannedArea',$,$,$);
#941=IFCPROPERTYSINGLEVALUE('NetPlannedArea',$,$,$);

/* placement and representation are not elaborated in this example */
#1284=IFCLOCALPLACEMENT( ... );
#1300=IFCPRODUCTREPRESENTATION ( ... );

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