IfcBlobTexture

Item	SPF	XML	Change	Description
IFC2x3 to IFC4
IfcBlobTexture
Mode	X	X	MODIFIED	Name changed from TextureType to Mode. Type changed from IfcSurfaceTextureEnum to IfcIdentifier. Instantiation changed to OPTIONAL.
Parameter		X	MODIFIED	Name changed from RasterFormat to Parameter. Instantiation changed to OPTIONAL. Aggregation changed from NONE to LIST.
RasterFormat	X	X	MODIFIED	Name changed from RasterCode to RasterFormat. Type changed from BOOLEAN to IfcIdentifier.
RasterCode			ADDED
IFC4 Addendum 1
IfcBlobTexture
RepeatS			MODIFIED	Type changed from BOOLEAN to IfcBoolean.
RepeatT			MODIFIED	Type changed from BOOLEAN to IfcBoolean.
RasterCode			MODIFIED	Type changed from BINARY to IfcBinary.

Semantic definitions at the entity

Entity definition

An IfcBlobTexture provides a 2-dimensional distribution of the lighting parameters of a surface onto which it is mapped. The texture itself is given as a single binary blob, representing the content of a pixel format file. The file format of the pixel file is given by the RasterFormat attribute and allowable formats are guided by where rule SupportedRasterFormat.

NOTE Toolbox specific implementations of the binary datatype may restrict the maximum length of the binary blob to capture the raster file content.

For interpretation of the texture nodes see IfcImageTexture definition.

HISTORY New entity in IFC2x3.

IFC4 CHANGE Data type of RasterCode has been corrected to BINARY.

Attribute definitions

#	Attribute	Type	Cardinality	Description	C
6	RasterFormat	IfcIdentifier	[1:1]	The format of the RasterCode often using a compression.	X
7	RasterCode	IfcBinary	[1:1]	Blob, given as a single binary, to capture the texture within one popular file (compression) format. The file format is provided by the RasterFormat attribute.	X

Formal Propositions

Rule	Description
SupportedRasterFormat	Currently the formats of bmp, jpg, gif and pgn, shall be supported.
RasterCodeByteStream	The size of the raster code shall be a multiple of 8 bits.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
IfcPresentationItem
IfcSurfaceTexture
1	RepeatS	IfcBoolean	[1:1]	The RepeatS field specifies how the texture wraps in the S direction. If RepeatS is TRUE (the default), the texture map is repeated outside the [0.0, 1.0] texture coordinate range in the S direction so that it fills the shape. If RepeatS is FALSE, the texture coordinates are clamped in the S direction to lie within the [0.0, 1.0] range.	X
2	RepeatT	IfcBoolean	[1:1]	The RepeatT field specifies how the texture wraps in the T direction. If RepeatT is TRUE (the default), the texture map is repeated outside the [0.0, 1.0] texture coordinate range in the T direction so that it fills the shape. If RepeatT is FALSE, the texture coordinates are clamped in the T direction to lie within the [0.0, 1.0] range.	X
3	Mode	IfcIdentifier	[0:1]	The Mode attribute is provided to control the appearance of a multi textures. The mode then controls the type of blending operation. The mode includes a MODULATE for a lit appearance, a REPLACE for a unlit appearance, and variations of the two. NOTE The applicable values for the Mode attribute are determined by view definitions or implementer agreements. It is recommended to use the modes described in ISO/IES 19775-1.2:2008 X3D Architecture and base components Edition 2, Part 1. See 18.4.3 MultiTexture for recommended values.	X
4	TextureTransform	IfcCartesianTransformationOperator2D	[0:1]	The TextureTransform defines a 2D transformation that is applied to the texture coordinates. It affects the way texture coordinates are applied to the surfaces of geometric representation itesm. The 2D transformation supports changes to the size, orientation, and position of textures on shapes. Mirroring is not allowed to be used in the IfcCartesianTransformationOperator	X
5	Parameter	IfcIdentifier	L[1:?]	The Parameter attribute is provided to control the appearance of a multi textures. The applicable parameters depend on the value of the Mode attribute. NOTE The applicable values for the list of Parameter attributes are determined by view definitions or implementer agreements. It is recommended to use the source and the function fields described in ISO/IES 19775-1.2:2008 X3D Architecture and base components Edition 2, Part 1. See 18.4.3 MultiTexture for recommended values. By convention, Parameter[1] shall then hold the source value, Parameter[2] the function value, Parameter[3] the base RGB color for select operations, and Parameter[4] the alpha value for select operations.	X
	IsMappedBy	IfcTextureCoordinate @Maps	S[0:?]	Texture coordinates, either provided by a corresponding list of texture vertices to vertex-based geometric items or by a texture coordinate generator, that applies the surface texture to the surfaces of the geometric items. IFC4 CHANGE New attribute added at the end of the attribute list.	X
	UsedInStyles	IfcSurfaceStyleWithTextures @Textures	S[0:?]		X
IfcBlobTexture
6	RasterFormat	IfcIdentifier	[1:1]	The format of the RasterCode often using a compression.	X
7	RasterCode	IfcBinary	[1:1]	Blob, given as a single binary, to capture the texture within one popular file (compression) format. The file format is provided by the RasterFormat attribute.	X

Formal representations

XSD Specification

 <xs:element name="IfcBlobTexture" type="ifc:IfcBlobTexture" substitutionGroup="ifc:IfcSurfaceTexture" nillable="true"/>

 <xs:complexType name="IfcBlobTexture">

  <xs:complexContent>

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

    <xs:attribute name="RasterFormat" type="ifc:IfcIdentifier" use="optional"/>

    <xs:attribute name="RasterCode" type="xs:hexBinary" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcBlobTexture

 SUBTYPE OF (IfcSurfaceTexture);

  RasterFormat : IfcIdentifier;

  RasterCode : IfcBinary;

 WHERE

  SupportedRasterFormat : SELF.RasterFormat IN ['BMP', 'JPG', 'GIF', 'PNG'];
  RasterCodeByteStream : BLENGTH(RasterCode) MOD 8 = 0;
END_ENTITY;

 EXPRESS-G diagram

	Textur - als Binärformat eingefügt
	Blob Texture
	Blob de texture