IFC (IFC4X3_ADD2) under development IfcDraughtingPreDefinedColour Semantic definition

The draughting pre defined colour is a pre defined colour for the purpose to identify a colour by name. Allowable names are:

  • 'black',
  • 'red',
  • 'green',
  • 'blue',
  • 'yellow',
  • 'magenta',
  • 'cyan',
  • 'white',
  • 'by layer'

The following table states the RGB values associated with the names given by the IfcDraughtingPreDefinedColour.

Colour name Red Green Blue
black 0 0 0
red 1.0 0 0
green 0 1.0 0
blue 0 0 1.0
yellow 1.0 1.0 0
magenta 1.0 0 1.0
cyan 0 1.0 1.0
white 1.0 1.0 1.0

If the colour name is 'by layer', colour values obtained from IfcPresentationLayerWithStyle.

Informal Propositions

  1. The value 'by layer' shall only be inserted, if the geometric representation item using the colour definition has an association to IfcPresentationLayerWithStyle, and if that instance of IfcPresentationLayerWithStyle has a valid colour definition for IfcCurveStyle or IfcSurfaceStyle (depending on what is applicable). Entity inheritance Attributes

# Attribute Type Description
IfcPreDefinedItem (1)
1 Name IfcLabel

The string by which the pre defined item is identified. Allowable values for the string are declared at the level of subtypes.

Table Formal propositions

Name Description

The inherited name for pre defined items shall only have the value of one of the following words.

SELF\IfcPreDefinedItem.Name IN ['black','red','green','blue','yellow',
     'magenta','cyan','white','by layer']
Table Formal representation

ENTITY IfcDraughtingPreDefinedColour
 SUBTYPE OF (IfcPreDefinedColour);
	PreDefinedColourNames : SELF\IfcPreDefinedItem.Name IN ['black','red','green','blue','yellow',
     'magenta','cyan','white','by layer'];
END_ENTITY; References

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Is this page difficult to understand? Let us know! Changelog IFC4

  • where rule, PreDefinedColourNames
  • where rule, WR31