An IfcFillAreaStyle provides the style table for presentation information assigned to annotation fill areas or surfaces for hatching and tiling. The IfcFillAreaStyle defines hatches as model hatches, that is, the distance between hatch lines, or the curve patterns of hatch lines are given in model space dimensions (that have to be scaled using the target plot scale). The IfcFillAreaStyle allows for the following combinations of defining the style of hatching and tiling:

• Solid fill for areas and surfaces by only assigning IfcColour to the set of FillStyles. It then provides the background colour for the filled area or surface.

NOTE  Color information of surfaces for rendering is assigned by using IfcSurfaceStyle, not by using IfcFillAreaStyle.

• Vector based hatching for areas and surfaces based on a single row of hatch lines by assigning a single instance of IfcFillAreaStyleHatching to the set of FillStyles.
• If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the hatching.
• Vector based hatching for areas and surfaces based on two (potentially crossing) rows of hatch lines by assigning two instances of IfcFillAreaStyleHatching to the set of FillStyles.
• If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the hatching.

NOTE  Assigning more then two instances of IfcFillAreaStyleHatching to define three or more rows of hatch lines is not encouraged.

• Tiling for areas and surfaces by assigning a single instance of IfcFillAreaStyleTiles to the set of FillStyles.
• If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the tiling.

• Externally defined hatch style by assigning a single instance of IfcExternallyDefinedHatchStyle to the set of FillStyles.
  • If an instance of IfcColour is assigned in addition to the set of FillStyles, it provides the background colour for the hatching.

Measures given to a hatch or tile pattern are given in global drawing length units.

NOTE  Global units are defined at the single IfcProject instance, given by UnitsInContext:IfcUnitAssignment, the same units are used for the geometric representation items and for the style definitions.

The measure values for hatch or tile pattern apply to the model space with a target plot scale provided for the correct appearance in the default plot scale. For different scale and projection dependent fill area styles a different instance of IfcFillAreaStyle needs to be used by IfcPresentationStyleAssignment for different IfcGeometricRepresentationSubContext dependent representations.

NOTE  the target plot scale is given by IfcGeometricRepresentationSubContext.TargetScale.

An IfcFillAreaStyle can be assigned to IfcFillArea via the IfcPresentationStyleAssignment through an intermediate IfcStyledItem or subtype IfcAnnotationFillAreaOccurrence.

NOTE  Definition according to ISO/CD 10303-46:1992
The style for filling visible curve segments, annotation fill areas or surfaces with tiles or hatches.

NOTE  Corresponding ISO 10303 name: fill_area_style. Please refer to ISO/IS 10303-46:1994 for the final definition of the formal standard.

HISTORY  New entity in IFC2x2.

DEPRECATION  The use of IfcFillAreaStyleTiles is deprecated, as its definition might change is future releases.