Houdini to AE camera animation clipboard exporter (now with Zoom! Woo!)

Houdini - copy camera animation data to clipboard.py

#  Houdini to After Effects camera animation exporter
#  This version: 7/11/2018, by Howard Matthews - [email protected]
#  Copyright: CC-0 - use and abuse. Please pass on the knowledge.

#  Note: there's no error-checking in this script, but it alters nothing within the Houdini scene, so it'll just
#        fail with an error if you try running it without a camera selected. No harm done.

import hou

theNodes = hou.selectedNodes()

#  1. Put this code on a new button on a shelf in Houdini.
#  2. Select a camera (or camera switcher) and press the button.
#     This script generates keyframe data for Position / Orientation / Zoom and copies it the system clipboard.
#
#  ** IMPORTANT NOTE **
#  In an ideal world, you could run this script, go to AE, create a camera, and hit Ctrl/Cmd-V and the animation data
#  would be pasted straight in. HOWEVER, for some reason, Houdini's Python interpreter and Adobe's clipboard handler
#  don't play nicely together. So there's an important additional step (at least on macOS - haven't tested on other OSs)
#
#  3. Open an empty text document, or a Stickies document - anywhere you can cut and paste text
#  4. Hit Paste [Cmd-V]
#  5. Select all text, and hit Copy [Cmd-A, Cmd-C]
#
#  6. Go to AE, first frame of your sequence, create a camera (if you haven't already), select it and hit Paste [Cmd-V].
#     The camera animation data should now appear correctly in AE.
#
#  7. If your AE camera isn't matching up with what you've rendered in Houdini, check the AE camera is set up the same way:
#     Go to the Camera settings in AE (select the camera, hit Shift-Cmd-Y) and check the resolution and the "film size" parameters.
#     Houdini calls the film size "Aperture", just to be confusing. It's typically 41.4214mm. In AE's camera settings dialog, check
#     that Units is set to millimetres, and Measure Film Size is set to Horizontally, then set the film size to whatever Houdini's
#     Aperture setting is.
#
#  8. Send nudes.

h = theNodes[0]

startFrame = int(hou.playbar.playbackRange()[0])
endFrame = int(hou.playbar.playbackRange()[1])
scale = 100.0

myOutputString = "Adobe After Effects 8.0 Keyframe Data\n\n"
myOutputString = myOutputString + "\tUnits Per Second\t25\n"
myOutputString = myOutputString + "\tSource Width\t1920\n"
myOutputString = myOutputString + "\tSource Height\t1080\n"
myOutputString = myOutputString + "\tSource Pixel Aspect Ratio\t1\n"
myOutputString = myOutputString + "\tComp Pixel Aspect Ratio\t1\n"
   



    # do the orientation:
    
myOutputString = myOutputString + "\nTransform\tOrientation\n"
myOutputString = myOutputString + "\tFrame\tX degrees\t\n"
  
for theFrame in range (startFrame,endFrame+1):
    x = h.worldTransformAtTime(hou.frameToTime(theFrame))
    xform = x.extractRotates('srt','zyx',hou.Vector3())
    myOutputString = myOutputString + "\t"+str(theFrame)+"\t"+str(xform[0])+"\t"+str(-xform[1])+"\t"+str(-xform[2])+"\n"

    
    # do the positions:
    
myOutputString = myOutputString + "\nTransform\tPosition\n"
myOutputString = myOutputString + "\tFrame\tX pixels\tY pixels\tZ pixels\n"
     
for theFrame in range (startFrame,endFrame+1):
    x = h.worldTransformAtTime(hou.frameToTime(theFrame))
    xform = x.extractTranslates('srt')
    myOutputString = myOutputString + "\t"+str(theFrame)+"\t"+str(xform[0]*scale)+"\t"+str(-xform[1]*scale)+"\t"+str(-xform[2]*scale)+"\n"
    
    
    # do the zoom:
    
myOutputString = myOutputString + "\nCamera Options\tZoom\n"
myOutputString = myOutputString + "\tFrame\tpixels\n"
     
for theFrame in range (startFrame,endFrame+1):
    foc = h.parm("focal").evalAsFloatAtFrame(theFrame)
    ape = h.parm("aperture").evalAsFloatAtFrame(theFrame)
    wid = h.parm("resx").evalAsIntAtFrame(theFrame)
    
        # After Effects uses zoom, rather than focal length:
    
    zoom = (foc * wid) / ape
    myOutputString = myOutputString + "\t"+str(theFrame)+"\t"+str(zoom)+"\n"
    
    
    

myOutputString = myOutputString + "\n\nEnd of Keyframe Data\n"


hou.ui.copyTextToClipboard(myOutputString)