Data in a .prc file is stored as a contiguous byte stream with a specified start and end offset relative to the beginning of the file. This data section can be compressed or uncompressed.

Data of various types in an uncompressed section occupy a specified number of bytes.

In the case of a compressed section, data is written in a bit-by-bit way without checking crossing byte boundaries. The last byte of the data section is padded with zero bits if it is necessary, then all the section data is compressed and written to the physical file.

Section data can be directly accessed because the section byte offset relative to the beginning of the file is stored in the .prc file.

Uncompressed and compressed PRC data types implemented in ODA PRC SDK are represented in the following table.

Uncompressed Data Types

PRC Data Type	Description	ODA PRC SDK Class or Data Type
UncompressedUnsignedInteger	Unsigned integer represented with 4 bytes	Can be represented with the OdUInt32 data type
UncompressedBlock	A block of binary data with specified size	Can be represented with an array of OdUInt8 data type
UncompressedFiles	An array of UncompressedBlock	Can be represented with an array of OdUInt8 data type
UncompressedUniqueId	An uncompressed unique identifier	Can be represented with the OdPrcUniqueId class

Compressed Simple Data Types

PRC Data Type	Description	ODA PRC SDK Class or Data Type
Bits(n)	n bits (from left to right) value	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
Boolean	Single bit boolean value	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
Character	Single 8 bits character	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
Integer	Compressed integer value	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
IntegerWithVariableBitNumber	Compressed integer with non-constant bits quantity	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
UnsignedInteger	Compressed unsigned integer	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
UnsignedIntegerWithVariableBitNumber	Compressed unsigned integer with non-constant bits quantity	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
NumberOfBitsThenUnsignedInteger	Number of bits occupied with an unsigned integer value	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
Float	A float value which occupies 4 bytes	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
Double	Compressed double value	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
DoubleWithVariableBitNumber	Compressed double value with non-constant bits quantity	Operations with data type are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler

Compressed Complex Data Types

PRC Data Type	Description	ODA PRC SDK Class or Data Type
CompressedEntityType	Surface or curve type for compressed boundary representation data	Operations with data types are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
CompressedUniqueId	Compressed unique identifier for PRC entities	Input/output operations are implemented in the OdPrcUniqueId class
String	UTF8 string	Operations with data types are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
CharacterArray	Array of characters	Operations with data types are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
ShortArray	Array of short integers	Operations with data types are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
CompressedIntegerArray	Array of integers	Operations with data types are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
CompressedIndiceArray	Array of indices	Operations with data types are implemented in ODA PRC SDK classes inherited from OdPrcCompressedFiler
UserData	User Defined data of various types	Operations with user data are implemented with the OdPrcUserData class. Working with UserDataStream can be implemented with the OdBitBinaryData class from ODA Kernel SDK Working with UserDataSubSection can be implemented with the OdBitBinaryData class from ODA Kernel SDK

Compressed Range Data Types

PRC Data Type	Description	ODA PRC SDK Class or Data Type
Infinite_param	Used for storing the infinitive parameter value	Implemented with kLowerInfinite, kUpperInfinite and kInfinite static members of the OdPrcDomain class
Interval	Interval value	Implemented with the OdPrcInterval class
Parameterization	Parameterization data used to reparameterize a curve	Implemented with the OdPrcParameterization class
OdPrcDomain	Domain for defining a surface.	Implemented with the OdPrcDomain class
UVParameterization	Surface reparameterization towards implicit parameterization	Implemented with the OdPrcUVParameterization class

Compressed Base Geometry Data Types

PRC Data Type	Description	ODA PRC SDK Class or Data Type
Vector2d	Two dimensional vector	Represented with the OdGeVector2d class from ODA Kernel SDK
Vector3d	Three dimensional vector	Represented with the OdGeVector3d class from ODA Kernel SDK
BoundingBox	Bounding box with sides parallel to the XYZ coordinate planes	Represented with the OdPrcBoundingBox class

See also

Supported Functionality and Platforms

PRC Format Concepts