This class is used for writing Open Inventor data files. It supports both ASCII (default) and binary formats and provides some convenience functions for opening and closing files. See OIV.Inventor.Helpers.SbFileHelper for more convenience functions. It can write to a buffer in memory as well as to a file. Since Open Inventor 8.1, OIV.Inventor.SoOutput can write compressed data in the lossless Zlib (aka gzip) format. Both ASCII and binary format files may be compressed.

An instance of OIV.Inventor.SoOutput is automatically created by OIV.Inventor.Actions.SoWriteAction and can be queried using the GetOutput() method in that class. This is typically the only instance needed. For example:

SoWriteAction writeAction = new SoWriteAction()  ;
writeAction.GetOutput().OpenFile( "output.iv" );
writeAction.Apply( root );
writeAction.GetOutput().CloseFile();

Note that file properties (binary, compression, header string, etc) should be set before calling OpenFile() or SetFilePointer().

File extensions The recommended file extension for Open Inventor format files, both ASCII and binary is ".iv". Open Inventor will automatically detect if the file is ASCII or binary based on the file header string. Compressed Open Inventor files may be given the extension ".ivz" for convenience, but it is not required. Open Inventor automatically detects compressed files.

File Header Open Inventor writes a human readable file header as the first line of both ASCII and binary format files. Since Open Inventor 8.0, the default file header looks like this: ASCII : "#Inventor V8.0 ascii" Binary: "#Inventor V8.0 binary LE" The two character code at the end of the binary header indicates if the file was written on a little-endian (LE) or big-endian (BE) machine. The version number string may change again in the future if incompatible changes are made to the file format. You can always query the current default headers using static methods GetDefaultASCIIHeader() and GetDefaultBinaryHeader().

All versions of Open Inventor from version 2.1 through version 7.x, wrote the version number string "V2.1" by default and did not append "LE" (or "BE") to the binary header. Open Inventor cannot, in general, load files containing a file header from a newer version. However all versions of Open Inventor can load files written by older versions and can load files containing the V2.1 file header. We recommend always using the default file header because newer versions enable performance enhancing features in the file format. If you need to write a file compatible with older versions, call OIV.Inventor.SoOutput.SetHeaderString(System.String) with "#Inventor V2.1 ascii" or "#Inventor V2.1 binary".

Reference