Real Flow/Houdini Extensions

The Real Flow/Houdini Extensions are a set of plugins enabling the user to exchange data between Houdini and Real Flow, thus leveraging the power of fluid dynamics in Real Flow with the flexibility and power of Houdini. Real Flow will export it's simulations as particles, meshes and SD files which contains much of the simulation data in the attributes of the exported data; these attributes are imported and available for use in Houdini. Real Flow will import many object formats, .OBJ, .DXF, etc. but the scene description file, the "SD File", also provides Real Flow with animation data and texture attributes which can be exported from Houdini into Real Flow.

The Real Flow SD File Export SOP
The Real Flow SD File Export SOP (Surface Operator) will export Houdini geometry to Real Flow SD (Scene Description) files including deforming objects.

The Real Flow Geometry Import SOP
The Real Flow geometry import SOP (Surface Operator) will read Real Flow particle, mesh or SD files and import them into Houdini as a collection of points (for the Real Flow particles) or a polygon mesh (for the Real Flow mesh and SD files) with all of the attributes generated in the simulation by Real Flow.

Download the software here!

Source Code Documentation

Look for bug fixes, feature additions, etc. here in the change log.

System Requirements:

The Next Limit (Real Flow) web site is at:
www.nextlimit.com

The Side Effects (Houdini) web site is at:
www.sidefx.com

Notes, tips, caveats and warnings:
Only triangular polygon primitives may be imported into Real Flow, so be very careful to make sure all of the desired geometry to be exported is in fact triangular polygons. There are occasions when by examining various SOP parameters alone, one may believe only triangular polygons have been generated but this may not be the case, it's sometimes necessary to verify by other means (caution: Real Flow will possibly crash if it's not the right format).

To check to see if the geometry you're trying to export to Real Flow is triangular polygon data, you may 1) write the geometry to disk as a Houdini .geo (ASCII) file and then examine the data for correctness (see the Houdini Geometry reference for details), or 2) use the "Echo Data to Console" switch on the Real Flow SD File Export SOP to echo the geometry data to the console for examination.

1) Point count for the geomtery being exported to Real Flow must not change when generating an SD file (Real Flow restriction).
2) The SD file imports into Houdini with texture data as point attributes and CG data as detail attributes.
3) When exporting, be very careful about making sure the geometry is in fact on composed of triangular ploygons. You can double check this by saving the geometry as a .geo file and examining it's contents.
4) Point order & particle ID: a) Real Flow generates it's particle ID's "backwards". b) Houdini's particle systems will keep the particle id consistant during the particles life, but the point number can change.
5) Real Flow mesh texture weights will always add up to 1.
6) When generating SD files, RF will sense when a new file has been written and will sometimes not be able o read the new file correctly, apparently because of cached data. It's best to use the "Replace Geometry" operation after you've regenerated an SD file.


Please keep in mind this should be considered to be beta software; there's no guarantee, warranty, etc., express or implied.

Please send any bug reports, feature requests or suggestions to support (at )digitalcinemaarts.com

Acknowledgments:
Special thanks to Doug Struthers who initiated this project and Victor Gonzalez of Next Limit.

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