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8.12.3.33 IfcSurfaceStyleShading

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8.12.3.33.1 Semantic definition

The IfcSurfaceStyleShading allows for colour information and transparency used for shading and simple rendering. The surface colour is used for colouring or simple shading of the assigned surfaces and the transparency for identifying translucency, where 0.0 is completely opaque, and 1.0 is completely transparent.

New entity in IFC2x.

8.12.3.33.2 Entity inheritance

8.12.3.33.3 Attributes

# Attribute Type Description
IfcSurfaceStyleShading (2)
1 SurfaceColour IfcColourRgb

The colour used to render the surface. The surface colour for visualisation is defined by specifying the intensity of red, green and blue.

2 Transparency OPTIONAL IfcNormalisedRatioMeasure

The transparency field specifies how "clear" an object is, with 1.0 being completely transparent, and 0.0 completely opaque. If not given, the value 0.0 (opaque) is assumed.

The definition of 1 being transparent and 0 being opaque is the opposite of the definition in alpha channels, where 0.0 is completely transparent and 1.0 is completely opaque. This definition is due to upward compatibility to previous versions of this standard in different to the definition in IfcIndexedColourMap.
Table 8.12.3.33.A

8.12.3.33.4 Formal representation

ENTITY IfcSurfaceStyleShading
 SUPERTYPE OF (ONEOF
	(IfcSurfaceStyleRendering))
 SUBTYPE OF (IfcPresentationItem);
	SurfaceColour : IfcColourRgb;
	Transparency : OPTIONAL IfcNormalisedRatioMeasure;
END_ENTITY;

8.12.3.33.5 References

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8.12.3.33.6 Changelog

8.12.3.33.6.1 IFC4

  • attribute, Transparency