IfcSurfaceStyleElementSelect

Definition from ISO/CD 10303-46:1992: The surface style element select is a selection of the different surface styles to use in the presentation of the side of a surface.

Definition from IAI: The select type only includes the IfcSurfaceStyleRendering (which is the equivalent to surface_style_rendering) from the select type surface_style_element_select. In addition it has the IfcSurfaceStyleLighting, which holds the exact physically based lighting properties for lighting based calculation algorithms (as the opposite to the rendering based calculation), the IfcSurfaceStyleRefraction (for more advanced refraction indices) and IfcSurfaceStyleWithTextures (to allow for image textures applied to surfaces). In addition an IfcExternallyDefinedSurfaceStyle can be selected that points into an external material library.

> NOTE The IfcSurfaceLightingProperties are needed for exact lighting calculation, because physically based lighting calculation algorithms need exact physically based parameters. The factors in IfcSurfaceStyleRendering lack the physical base, they are intended for rendering calculations, but a lighting calculation based software cannot use these values.

> NOTE: Corresponding STEP type: surface_style_element_select. Please refer to ISO/IS 10303-46:1994, p. 85 for the final definition of the formal standard.

> HISTORY: New Select type in IFC Release 2x2.

EXPRESS specification:

TYPE IfcSurfaceStyleElementSelect = SELECT
( | IfcSurfaceStyleShading, IfcSurfaceStyleLighting, IfcSurfaceStyleWithTextures, IfcExternallyDefinedSurfaceStyle, IfcSurfaceStyleRefraction);
END_TYPE;