Houdini to Fusion camera animation exporter script [U]

Send a camera (or other animated object) from Houdini to Fusion. This is a work in progress, but it works, so I figured it’s worth making available in case anyone’s desperate. If nothing else it’s useful example code for anyone trying to export data from Houdini.

To use:

  • In Houdini, right click on a Shelf (mebbe make a new shelf if you want to keep things neat) and choose Add Tool…
  • Paste the code linked below into the Script Tab of the dialog that pops up. Make sure “Python” is selected at the bottom of the dialog, and click Accept.

Tip: if you’ve added a new shelf to house this tool, don’t forget to save your desktop so it’ll show up automatically in future. If you forget, you can always find your new shelf listed among the others on the right-click-add shelf menu)

  • Now you can select any OBJ-level node – a camera perhaps – and click your new button. You’ll know it’s working if nothing at all seems to happen.
  • Switch over to Fusion, click somewhere in the Flow panel, and hit Ctrl/Cmd-V to paste… ta-da – you now have a new Camera_3D node, all keyframed up with position and rotation. If it wasn’t a camera you chose in Houdini, the new Fusion node will instead be a Custom Tool with 6 Number parameters for the position and rotation, which you can then hook up to any other parameters you need in Fusion.

Nothing to stop you pasting into a text editor first if you want to see what’s going to be created.

Caveats:

  • the only animation that’ll be carried over is rotation and translation—it’s up to you to set up the rest of the camera parameters correctly (field of view etc). Rotation order should carry across automatically, at least for camera objects.
  • No Euler wind-up or discontinuity filtering is implemented (yet)

To do:

  • Euler wind-up (ie dealing with rotations greater than 360° without wrapping) (Updated!)
  • Euler discontinuity filtering (so you may get jumps in rotation when the camera swings through an axis – the gimbal lock thing)(Updated!)
  • Focus distance animation, aperture and field-of-view settings will be carried across once I get my head round the way Fusion measures them
  • A bit of error checking would be nice
  • Pruning redundant keyframes (ie where the value doesn’t change between 3 or more consecutive frames)(Updated!)

Link: https://gist.github.com/howiemnet/9ab71 … dfdbdf4385

Comments / corrections / suggestions welcome as usual

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