how to set a channel reference in a Python script?

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I'm trying to set a channel reference by entering a string in a set operation:

transformnode = hou.node('obj/track').createNode('xform', “transform” + str(minmaxspeedindexpoint))
transformnode.parm('px').set('ch(“../font' + str(x) + ‘/tx”)’)

but it's complaining that I can't set a numerical value to a non-numerical value.
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Moin,

what's “x”? If it is undefined, it's definitely a non-numerical value (note that you are escaping from your quote in the parm().set() sequence, probably intentionally so).

One way to debug something like this is to set variables you use manually in a python shell (Houdini offers that conveniently) and step by step recreating the expression until you get the error. Then the last step/change you made is the culprit.


Marc
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Out of here. Being called a dick after having supported Houdini users for years is over my paygrade.
I will work for money, but NOT for "you have to provide people with free products" Indie-artists.
Good bye.
https://www.marc-albrecht.de [www.marc-albrecht.de]
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you nees to use .setExpression() instead of .set()
transformnode = hou.node('obj/track').createNode('xform', "transform" + str(minmaxspeedindexpoint))
transformnode.parm('px').setExpression('ch("../font' + str(x) + '/tx")')
you can also use string formatting to build your strings
transformnode = hou.node('obj/track').createNode('xform', "transform{}".format(minmaxspeedindexpoint))
transformnode.parm('px').setExpression('ch("../font{}/tx")'.format(x))
or the old string formatting, not sure whether that's being phased out or not, but for now may be shorter sometimes
transformnode = hou.node('obj/track').createNode('xform', "transform%d" % minmaxspeedindexpoint)
transformnode.parm('px').setExpression('ch("../font%d/tx")' % x)
Edited by tamte - April 4, 2020 18:58:56
Tomas Slancik
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Method Studios, NY
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thanks. setExpression works.
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