BIN File Format

  • The RealFlow Particle BIN file (.BIN) is a binary file format developed by Next Limit and used for data exchange between RealFlow and other 3D applications.
  • Krakatoa allows the loading of RealFlow 3 and RealFlow 4 Particle BIN files in both Krakatoa Particle Flow Operators and Krakatoa Particle Loader objects.
  • It also supports saving to RealFlow 4 Particle BIN files which are compatible with RealFlow 5, RealFlow 2012 and higher.

Format Variations

  • It is important to be aware that RealFlow supports two different file formats with the BIN extension - a Particle BIN file and a Geometry BIN file.
    • Krakatoa supports only the Particle variation of the BIN file format.
  • The BIN file format has gone through many revisions. The flavor which Krakatoa writes is revision 9 from RealFlow 4.
  • This format is also used by RealFlow 5, 2012 and higher.

Format Specification

  • The BIN file format specifications are provided by Next Limit in PDF format as part of the RealFlow application (included in the evaluation version).
  • Please download the evaluation version of RealFlow or purchase the full product if you need the specs.

Special Considerations

  • The BIN file can contain a Density channel which has a completely different meaning in the context of RealFlow and in some cases can default to 0.0.
  • As result, such a file will fail to appear in the Krakatoa rendering because all particles will be seen as completely transparent.
  • Adding a Magma modifier and setting the Density channel to 1.0 is the workaround in this case.
  • In the RealFlow application, file names are expected to have EXACTLY 5 trailing digits (no more, no less).
    • Anything else will fail to load in RealFlow or its associated I/O plug-ins for 3D application, but will load in Krakatoa without problems.
    • Krakatoa provides an optional GUI-level check to ensure BIN files are saved with five trailing digits.
  • When older versions of RealFlow saved particle files, they appended the digits immediately after the emitter name.
    • This could produce files like Circle0100014.bin, which Krakatoa would interpret as at frame 100014 rather than at frame 14.
    • One possible precaution measure to avoid this was adding an underscore after the emitter’s name in RealFlow, for example Circle01_ would output Circle01_00014.bin and would cause no problems in Krakatoa.
    • This problem has been addressed in newer versions of RealFlow.
  • If the BIN files have already been saved without a trailing underscore, you can load the BIN sequence in a Krakatoa PRT Loader and use the Offset field to shift the animation by as many frames as needed.
    • In the above example, entering 100000 in the Offset field will play frame 100000 on frame 0, causing the file Circle0100014.bin to be loaded correctly on frame 14.
    • Then you could resave the particles to a new PRT or BIN sequence using Krakatoa with correct names with underscore at the end, or just use the original sequence with the Offset as is.

Coordinate System And Scene Scane Conversion

  • RealFlow uses a left-handed Y-up coordinate system, while Krakatoa MX expects right-haded Z-up, and Krakatoa MY uses Maya’s right-handed Y-up coordinate system.
    • The Krakatoa PRT Loader assumes that a BIN file always contains RealFlow data in left-handed Y-up coordinates, and will perform automatic coordinate system conversion to the host 3D application’s coordinate system.
  • While the default system unit scale of RealFlow is Meters, the units can be customized freely, and the BIN file contains Metadata describing this scale.
    • The Krakatoa PRT Loader in Krakatoa 2.4.1 and higher will perform automatic unit re-scaling of relevant channels like Position and Velocity.

RPC Files

  • Krakatoa 2.3.1 and higher also supports the loading of RealFlow .RPC files.
  • They can be used as an alternative path for bringing particle simulation data from RealFlow into Krakatoa.
  • However, Krakatoa does not implement the saving of .RPC files, so the .BIN file format remains the least common denominator for bi-directional data exchange between RealFlow and Krakatoa.

BIN Files And RealFlow

  • Recent versions of RealFlow support data export to the Krakatoa PRT file format.
    • However, some of the channel mapping is implemented using different naming conventions (for example the “ID” channel is named “Id”), which can lead to problems when loading the data.
    • Also, the first versions of RealFlow to support the PRT file format impemented the v1.0 specification, and thus lacked coordinate system and system units scale Metadata records.
  • For these reasons, using the BIN file format with its automatic coordinate system and units conversion into the latest versions of Krakatoa to exchange data between RealFlow and Krakatoa is encouraged.