Defined in File Ifc4.h
IfcMaterialLayerWithOffsets: public Ifc4::IfcMaterialLayer¶
It defines the assignment of two offset values for a material layer in its intended use within a material layer set. Offsets are applied to the edges of layered elements (that is, in directions perpendicular to the layer set direction). Offsets shall not be used in layer set direction, that is, for modelling gaps (or overlaps) between layers; gaps shall be modeled as layers with appropriate material assignment for the void.
EXAMPLE At the top of a standard wall, with shape representation SweptSolid, offset of a given layer can be specified in the direction of the extrusion (positive Z axis), applied at the start or end (extruded from bottom to top), and with a positive (extending above extrusion) or negative (ending below extrusion).
Take a standard wall with the outer material layer for the external isolation extending above extrusion by 100mm, but starting at the same base height. In this case the following values are set:
OffsetDirection = .AXIS3. OffsetValues = 0.0 OffsetValues = 100.0 (default unit assumed to be mm)
HISTORY New Entity in IFC2x4.
The OffestDirection shall not be identical to the LayerSetDirection of the corresponding IfcMaterialLayerSetUsage The attribute ReferenceExtent shall be asserted at the corresponding IfcMaterialLayerSetUsage
Attribute use definition The OffsetValues and OffsetDirection correspond to the definitions ReferenceExtent and LayerSetDirection at the IfcMaterialLayerSetUsage. Figure 289 shows an example of applying the OffsetValues to the material layers of a standard wall.
Figure 289 — Material layer with offsets
Orientation of the offset; shall be perpendicular to the parent layer set direction.
The numerical value of layer offset, in the direction of the axis assigned by the attribute OffsetDirection. The OffsetValues identifies the offset from the lower position along the axis direction (normally the start of the standard extrusion), the OffsetValues identifies the offset from the upper position along the axis direction (normally the end of the standard extrusion),.
IfcMaterialLayerWithOffsets(::Ifc4::IfcMaterial *v1_Material, double v2_LayerThickness, boost::optional<bool> v3_IsVentilated, boost::optional<std::string> v4_Name, boost::optional<std::string> v5_Description, boost::optional<std::string> v6_Category, boost::optional<int> v7_Priority, ::Ifc4::IfcLayerSetDirectionEnum::Value v8_OffsetDirection, std::vector<double> v9_OffsetValues)¶