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IfcPropertyTableValue

Definition from IAI: A property with a range value (IfcPropertyTableValue) defines a property object which has two lists of (numeric or descriptive) values assigned, the values specifying a table with two columns. The defining values provide the first column and establish the scope for the defined values (the second column). Interpolations are out of scope of the IfcPropertyTableValue. An optional Expression attribute may give the equation used for deriving the range value, which is for information purposes only.

The IfcPropertyTableValue defines a defining/defined property value combination for which the property name, the table with defining and defined values with measure type (and optional the units for defining and defined values)are given.

The units are handled by the DefiningUnit and DefinedUnit attributes:

The IfcPropertyTableValue allows for the specification of a table of defining/defined value pairs of the property description.

Examples of a property with range value are:

Name DefiningValues DefiningValue Type
(through IfcValue)		 DefinedValues DefinedValue Type
(through IfcValue)		 DefingUnit DefinedUnit
SoundTransmissionLoss 100 IfcFrequencyMeasure 20 IfcNumericMeasure - dB
  200 IfcFrequencyMeasure 42 IfcNumericMeasure    
  400 IfcFrequencyMeasure 46 IfcNumericMeasure    
  800 IfcFrequencyMeasure 56 IfcNumericMeasure    
  1600 IfcFrequencyMeasure 60 IfcNumericMeasure    
  3200 IfcFrequencyMeasure 65 IfcNumericMeasure    

HISTORY: New entity in IFC Release 2x.

ISSUES: See issue log for changes made in IFC Release 2x.

Informal propositions:

  1. The List of DerivedValues and the List of DerivingValues are corresponding lists.

EXPRESS specification:

ENTITY IfcPropertyTableValue
SUBTYPE OF ( IfcSimpleProperty);
DefiningValues  :  LIST [1:?] OF UNIQUE IfcValue;
DefinedValues  :  LIST [1:?] OF IfcValue;
Expression  :  OPTIONAL IfcText;
DefiningUnit  :  OPTIONAL IfcUnit;
DefinedUnit  :  OPTIONAL IfcUnit;
WHERE
WR1  :  SIZEOF(DefiningValues) = SIZEOF(DefinedValues);
WR2  :  SIZEOF(QUERY(temp <* SELF.DefiningValues | TYPEOF(temp) <> TYPEOF(SELF.DefiningValues[1])))=0;
WR3  :  SIZEOF(QUERY(temp <* SELF.DefinedValues | TYPEOF(temp) <> TYPEOF(SELF.DefinedValues[1])))=0;
END_ENTITY;

Attribute definitions:

DefiningValues  :  List of defining values, which determine the defined values.
DefinedValues  :  Defined values which are applicable for the scope as defined by the defining values.
Expression  :  Expression for the derivation of defined values from the defining values, the expression is given for information only, i.e. no automatic processing can be expected from the expression.
DefiningUnit  :  Unit for the defining values, if not given, the default value for the measure type (given by the TYPE of the defining values) is used as defined by the global unit assignment at IfcProject.
DefinedUnit  :  Unit for the defined values, if not given, the default value for the measure type (given by the TYPE of the defined values) is used as defined by the global unit assignment at IfcProject.

Formal Propositions:

WR1  :  The number of members in the list of defining values shall be the same as the number of members in the list of defined values.
WR2  :  All values within the list of defining values shall have the same measure type.
WR3  :  All values within the list of defined values shall have the same measure type.

References (1):

Name Type Referred through Express-G
IfcSimpleProperty Entity
Subtype
Diagram 1

Inheritance graph

ENTITY IfcPropertyTableValue;
ENTITY IfcProperty;
Name  :  IfcIdentifier;
Description  :  OPTIONAL IfcText;
INVERSE
PartOfComplex  :  SET [0:1] OF IfcComplexProperty FOR HasProperties;
ENTITY IfcSimpleProperty;
ENTITY IfcPropertyTableValue;
DefiningValues  :  LIST [1:?] OF UNIQUE IfcValue;
DefinedValues  :  LIST [1:?] OF IfcValue;
Expression  :  OPTIONAL IfcText;
DefiningUnit  :  OPTIONAL IfcUnit;
DefinedUnit  :  OPTIONAL IfcUnit;
END_ENTITY;