4.8.2.4 Axis Geometry

Elements following a path provide an 'Axis' representation indicating a line segment or any arbitrary open bounded curve. Examples of such elements include walls, beams, columns, pipes, ducts, and cables. For elements that have a material profile set association indicating cross-section, a 'Body' representation may be generated based on the axis curve and material profiles. Curve styles may indicate particular colors, line thicknesses, and dash patterns for 2D rendering.

The representation identifier of the axis representation is:

EXAMPLE  A two-dimensional bounded curve is used as the wall axis in standard walls, a three-dimensional bounded curve is used as the reference axis in standard columns.

Figure 72 illustrates an instance diagram.

Axis GeometryIfcElementIfcProductDefinitionShapeIfcShapeRepresentationIfcGeometricRepresentationContextIfcLabelIfcLabel

Figure 72 — Axis Geometry

mvdXML Specification
<?xml version="1.0"?>
<ConceptTemplate xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" uuid="3bf716df-3990-4bfc-8045-9e4011c9b622" name="Axis Geometry" status="sample" applicableSchema="IFC4" applicableEntity="IfcElement">
  <Rules>
    <AttributeRule AttributeName="Representation">
      <EntityRules>
        <EntityRule EntityName="IfcProductDefinitionShape">
          <AttributeRules>
            <AttributeRule AttributeName="Representations">
              <EntityRules>
                <EntityRule EntityName="IfcShapeRepresentation">
                  <AttributeRules>
                    <AttributeRule AttributeName="ContextOfItems">
                      <EntityRules>
                        <EntityRule EntityName="IfcGeometricRepresentationContext" />
                      </EntityRules>
                    </AttributeRule>
                    <AttributeRule RuleID="Identifier" AttributeName="RepresentationIdentifier">
                      <EntityRules>
                        <EntityRule EntityName="IfcLabel">
                          <Constraints>
                            <Constraint Expression="Identifier[Value] = 'Axis'" />
                          </Constraints>
                        </EntityRule>
                      </EntityRules>
                    </AttributeRule>
                    <AttributeRule RuleID="Type" AttributeName="RepresentationType">
                      <EntityRules>
                        <EntityRule EntityName="IfcLabel" />
                      </EntityRules>
                    </AttributeRule>
                    <AttributeRule RuleID="Items" AttributeName="Items" />
                  </AttributeRules>
                </EntityRule>
              </EntityRules>
            </AttributeRule>
            <AttributeRule AttributeName="Name" />
            <AttributeRule AttributeName="Description" />
          </AttributeRules>
        </EntityRule>
      </EntityRules>
    </AttributeRule>
  </Rules>
  <SubTemplates>
    <ConceptTemplate uuid="782444e8-d681-475a-9034-a9e7f53c6d65" name="Axis 2D Geometry" status="sample" applicableSchema="IFC4" applicableEntity="IfcElement">
      <Rules>
        <AttributeRule AttributeName="Representation">
          <EntityRules>
            <EntityRule EntityName="IfcProductDefinitionShape">
              <AttributeRules>
                <AttributeRule AttributeName="Representations">
                  <EntityRules>
                    <EntityRule EntityName="IfcShapeRepresentation">
                      <AttributeRules>
                        <AttributeRule AttributeName="ContextOfItems">
                          <EntityRules>
                            <EntityRule EntityName="IfcGeometricRepresentationContext" />
                          </EntityRules>
                        </AttributeRule>
                        <AttributeRule RuleID="Identifier" AttributeName="RepresentationIdentifier">
                          <EntityRules>
                            <EntityRule EntityName="IfcLabel">
                              <Constraints>
                                <Constraint Expression="Identifier[Value] = 'Axis'" />
                              </Constraints>
                            </EntityRule>
                          </EntityRules>
                        </AttributeRule>
                        <AttributeRule RuleID="Type" AttributeName="RepresentationType">
                          <EntityRules>
                            <EntityRule EntityName="IfcLabel">
                              <Constraints>
                                <Constraint Expression="Type[Value] = 'Curve2D'" />
                              </Constraints>
                            </EntityRule>
                          </EntityRules>
                        </AttributeRule>
                        <AttributeRule RuleID="Items" AttributeName="Items">
                          <EntityRules>
                            <EntityRule EntityName="IfcBoundedCurve" />
                          </EntityRules>
                        </AttributeRule>
                      </AttributeRules>
                    </EntityRule>
                  </EntityRules>
                </AttributeRule>
                <AttributeRule AttributeName="Name" />
                <AttributeRule AttributeName="Description" />
              </AttributeRules>
            </EntityRule>
          </EntityRules>
        </AttributeRule>
      </Rules>
    </ConceptTemplate>
    <ConceptTemplate uuid="b894d8cb-fb41-45ec-ba18-72cac6baff34" name="Axis 3D Geometry" status="sample" applicableSchema="IFC4" applicableEntity="IfcElement">
      <Rules>
        <AttributeRule AttributeName="Representation">
          <EntityRules>
            <EntityRule EntityName="IfcProductDefinitionShape">
              <AttributeRules>
                <AttributeRule AttributeName="Representations">
                  <EntityRules>
                    <EntityRule EntityName="IfcShapeRepresentation">
                      <AttributeRules>
                        <AttributeRule AttributeName="ContextOfItems">
                          <EntityRules>
                            <EntityRule EntityName="IfcGeometricRepresentationContext" />
                          </EntityRules>
                        </AttributeRule>
                        <AttributeRule RuleID="Identifier" AttributeName="RepresentationIdentifier">
                          <EntityRules>
                            <EntityRule EntityName="IfcLabel">
                              <Constraints>
                                <Constraint Expression="Identifier[Value] = 'Axis'" />
                              </Constraints>
                            </EntityRule>
                          </EntityRules>
                        </AttributeRule>
                        <AttributeRule RuleID="Type" AttributeName="RepresentationType">
                          <EntityRules>
                            <EntityRule EntityName="IfcLabel">
                              <Constraints>
                                <Constraint Expression="Type[Value] = 'Curve3D'" />
                              </Constraints>
                            </EntityRule>
                          </EntityRules>
                        </AttributeRule>
                        <AttributeRule RuleID="Items" AttributeName="Items">
                          <EntityRules>
                            <EntityRule EntityName="IfcBoundedCurve" />
                          </EntityRules>
                        </AttributeRule>
                      </AttributeRules>
                    </EntityRule>
                  </EntityRules>
                </AttributeRule>
                <AttributeRule AttributeName="Name" />
                <AttributeRule AttributeName="Description" />
              </AttributeRules>
            </EntityRule>
          </EntityRules>
        </AttributeRule>
      </Rules>
    </ConceptTemplate>
  </SubTemplates>
</ConceptTemplate>

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