Quick example: on my HDA I have 2 parms called 'extratx' and 'finaltx', with a Python expression running on 'finaltx' that reads the value of 'extratx', performs some additional work, then returns the value:
node = hou.pwd() extratx = node.parm('extratx').eval() return(extratx*3)
When I plug that HDA into an HDA Processor and Generate work items though, I get an error along the lines of
Unable to evaluate expression (
Traceback (most recent call last):
File "<stdin>", line 3, in expression
AttributeError: 'NoneType' object has no attribute 'eval'
It looks like the expression is trying to evaluate 'extratx', which should now be 'hdap_extratx'. I thought these parm references were supposed to be updated on the fly by the HDA Processor, so I must be doing something wrong with my setup.
I'm aware that hython will instantiate a fresh copy of the HDA when it cooks, but if I can't generate the work items I can't get that far with it.
Any thoughts? My issue is very similar to this post:
and related to this one as well:
but I haven't been able to solve my problem from those discussions. Any additional help would be appreciated.