IfcBlock

Natural language names
Quader
Block
Parallélépipède
Semantic definitions at the entity
Entity definition

The IfcBlock is a Construction Solid Geometry (CSG) 3D primitive. It is defined by a position and a positve distance along the three orthogonal axes. The inherited Position attribute has the IfcAxisPlacement3D type and provides:

The XLength, YLength, and ZLength attributes define the size of the IfcBlock along the three axes.

block

Figure 328 illustrates geometric parameters of a block where the block positioned within its own placement coordinate system. The values for XLength, YLength, and ZLength are applied to the positive direction of the X, Y, and Z axis.

Figure 328 — Block geometry

 
NOTE  Definition according to ISO/CD 10303-42:1992
A block is a solid rectangular parallelepiped, defined with a location and placement coordinate system. The block is specified by the positive lengths x, y, and z along the axes of the placement coordinate system, and has one vertex at the origin of the placement coordinate system.
NOTE  Entity adapted from block defined in ISO 10303-42.
HISTORY  New entity in IFC2x3.

Texture definition

On each side face, textures are aligned facing upright. On the top and bottom faces, textures are aligned facing front-to-back. Textures are stretched or repeated to the extent of each face according to RepeatS and RepeatT.

Figure 329 illustrates default texture mapping with a clamped texture (RepeatS=False and RepeatT=False). The image on the left shows the texture where the S axis points to the right and the T axis points up. The image on the right shows the texture applied to the geometry where the X axis points back to the right, the Y axis points back to the left, and the Z axis points up.

 

texture
Side Normal Origin X Origin Y Origin Z S Axis T Axis
Left -X 0 +YLength 0 -Y +Z
Right +X +XLength 0 0 +Y +Z
Front -Y 0 0 0 +X +Z
Back +Y +XLength +YLength 0 -X +Z
Bottom -Z 0 +YLength 0 +X -Y
Top +Z 0 0 +ZLength +X +Y

Figure 329 — Block textures

Attribute definitions
#AttributeTypeCardinalityDescription G
2XLengthIfcPositiveLengthMeasure The size of the block along the placement X axis. It is provided by the inherited axis placement through SELF\IfcCsgPrimitive3D.Position.P[1].X
3YLengthIfcPositiveLengthMeasure The size of the block along the placement Y axis. It is provided by the inherited axis placement through SELF\IfcCsgPrimitive3D.Position.P[2].X
4ZLengthIfcPositiveLengthMeasure The size of the block along the placement Z axis. It is provided by the inherited axis placement through SELF\IfcCsgPrimitive3D.Position.P[3].X
Inherited definitions from supertypes
Entity inheritance IfcCsgPrimitive3D IfcGeometricRepresentationItem IfcRepresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRepresentationItem
LayerAssignmentIfcPresentationLayerAssignment
@AssignedItems
S[0:1]Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.
IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.
IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
X
StyledByItemIfcStyledItem
@Item
S[0:1]Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.
IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
X
IfcGeometricRepresentationItem
IfcCsgPrimitive3D
1PositionIfcAxis2Placement3D The placement coordinate system to which the parameters of each individual CSG primitive apply.X
Dim
:=3
IfcDimensionCountThe space dimensionality of this geometric representation item, it is always 3. X
IfcBlock
2XLengthIfcPositiveLengthMeasure The size of the block along the placement X axis. It is provided by the inherited axis placement through SELF\IfcCsgPrimitive3D.Position.P[1].X
3YLengthIfcPositiveLengthMeasure The size of the block along the placement Y axis. It is provided by the inherited axis placement through SELF\IfcCsgPrimitive3D.Position.P[2].X
4ZLengthIfcPositiveLengthMeasure The size of the block along the placement Z axis. It is provided by the inherited axis placement through SELF\IfcCsgPrimitive3D.Position.P[3].X
Examples
Formal representations
XML Specification
 <xs:element name="IfcBlock" type="ifc:IfcBlock" substitutionGroup="ifc:IfcCsgPrimitive3D" nillable="true"/>
 <xs:complexType name="IfcBlock">
  <xs:complexContent>
   <xs:extension base="ifc:IfcCsgPrimitive3D">
    <xs:attribute name="XLength" type="ifc:IfcPositiveLengthMeasure" use="optional"/>
    <xs:attribute name="YLength" type="ifc:IfcPositiveLengthMeasure" use="optional"/>
    <xs:attribute name="ZLength" type="ifc:IfcPositiveLengthMeasure" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcBlock
 SUBTYPE OF (IfcCsgPrimitive3D);
  XLength : IfcPositiveLengthMeasure;
  YLength : IfcPositiveLengthMeasure;
  ZLength : IfcPositiveLengthMeasure;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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