IFC (IFC4X3_ADD1) development IfcTextureMap Semantic definition

An IfcTextureMap provides the mapping of the 2-dimensional texture coordinates to the surface onto which it is mapped. It is used for mapping the texture to surfaces of vertex based geometry models, such as

The IfcTextureMap has a list of TextureVertex, that corresponds to the points of the outer face bound of the vertex based geometry item. The corresponding pair of lists is:

  1. the list of Polygon of the IfcFaceOuterBound of type IfcCartesianPoint, and
  2. the list of Vertices of type IfcTextureVertex.

Each IfcTextureVertex (given as S, T coordinates of the 2-dimension texture coordinate system) corresponds to the geometric coordinates of the IfcCartesianPoint (given as 3-dimension X, Y, and Z coordinates within the object coordinate system of the geometric item).

IfcTextureMap_fig-1.png 35,6 KB
Figure — Texture map

Figure illustrates applying a texture map to a vertex based geometry.

Informal Propositions:

  1. The IfcFace referenced in AppliedTo shall be used by the vertex based geometry, to which this texture map is assigned to by through the IfcStyledItem. Entity inheritance Attributes

# Attribute Type Description
IfcTextureCoordinate (1)
1 Maps LIST [1:?] OF IfcSurfaceTexture

Reference to the one (or many in case of multi textures with identity transformation to geometric surfaces) subtype(s) of IfcSurfaceTexture that are mapped to a geometric surface by the texture coordinate transformation.

Click to show 1 hidden inherited attributes Click to hide 1 inherited attributes
IfcTextureMap (2)
2 Vertices LIST [3:?] OF IfcTextureVertex

List of texture coordinate vertices that are applied to the corresponding points of the polyloop defining a face bound.

3 MappedTo IfcFace

The face that defines the corresponding list of points along the bounding poly loop of the face outer bound.

Table Formal representation

ENTITY IfcTextureMap
 SUBTYPE OF (IfcTextureCoordinate);
	Vertices : LIST [3:?] OF IfcTextureVertex;
	MappedTo : IfcFace;
END_ENTITY; References

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Is this page difficult to understand? Let us know! Changelog IFC4

  • attribute, MappedTo
  • where rule, WR11
  • attribute TextureMaps name, Changed from "TextureMaps" to "Vertices"
  • attribute TextureMaps type, Changed from "set[1:?] of IfcVertexBasedTextureMap" to "list[3:?] of IfcTextureVertex"