IfcSphere

Semantic definitions at the entity

Entity definition

The IfcSphere is a Construction Solid Geometry (CSG) 3D primitive. It is a solid where all points at the surface have the same distance from the center point. The inherited Position attribute defines the IfcAxisPlacement3D and provides:

SELF\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive.
SELF\IfcCsgPrimitive3D.Position.Location: The center of the sphere.
SELF\IfcCsgPrimitive3D.Position.Position[3]: The z axis points at its positve direction towards the north pole, and by its negative directions towards the south pole.

	EXAMPLE Figure 352 illustrates geometric parameters of the sphere. The sphere is positioned within its own placement coordiante system relative to the object coordinate system. The origin is the center of the sphere.
Figure 352 — Sphere geometry

NOTE Definition according to ISO/CD 10303-42:1992
A sphere is a CSG primitive with a spherical shape defined by a centre and a radius.

NOTE Entity adapted from sphere defined in ISO 10303-42.

HISTORY New entity in IFC2x3.

Texture Use Definition

Textures are aligned facing upright with origin at the back (+Y direction) revolving counter-clockwise. Textures are stretched or repeated to the extent of the circumference at the equator according to RepeatS and RepeatT.

Figure 353 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.

Side	Normal	Origin X	Origin Y	Origin Z	S Axis	T Axis
Side	+Y	0	+Radius	0	(-X, then curving counter-clockwise)	(+Z, then curving towards top)

Figure 353 — Sphere textures

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
2	Radius	IfcPositiveLengthMeasure		The radius of the sphere.	X

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @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
	StyledByItem	IfcStyledItem @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
1	Position	IfcAxis2Placement3D		The placement coordinate system to which the parameters of each individual CSG primitive apply.	X
	Dim :=3	IfcDimensionCount		The space dimensionality of this geometric representation item, it is always 3.	X
IfcSphere
2	Radius	IfcPositiveLengthMeasure		The radius of the sphere.	X

Formal representations

XML Specification

 <xs:element name="IfcSphere" type="ifc:IfcSphere" substitutionGroup="ifc:IfcCsgPrimitive3D" nillable="true"/>

 <xs:complexType name="IfcSphere">

  <xs:complexContent>

   <xs:extension base="ifc:IfcCsgPrimitive3D">

    <xs:attribute name="Radius" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcSphere

 SUBTYPE OF (IfcCsgPrimitive3D);

  Radius : IfcPositiveLengthMeasure;

END_ENTITY;

 EXPRESS-G diagram

	Kugel
	Sphere
	Sphère