How to check if a value of any of the otl's parameters has changed.

[kgoossens]

Hi everyone,

 

I need to be able to change a value inside my otl based on any parameter change of the otl. Is there a method to check that?

 

Cheers,

 

Kim

[MrScienceOfficer]

You can add a callback on the node.

node.addEventCallback(hou.nodeEventType.ParmTupleChanged, call_func)

I think that covers all parms, not just parmTuples but I'm not sure.

[galagast]

Hi, I tested this out. Hopefully the attached HDA example is something close to what you're after.

Changing the parameters of HDA will also affect a node's parameter inside it. I assigned the ParmTupleChanged callback through the onCreated event (and removed the callback through the OnDeleted event).

Although whenever saving the definition, an error pops up.
It seems to error out due to a function eval() call to an undefined variable - which will only be filled after the callback fires. I'm not sure how to bypass that >__<

H16.5.268 Indie - otl_parm_callback.hdalc

On a side note, the example on the docs for the usage of a .ParmTupleChanged (under the addEventCallback) is probably incorrect.. I found this thread which suggested the correct syntax.

[MrScienceOfficer]

Another option would be to mirror your HDAs interface on a python node so when any parameter changes the node will be cooked.

[kgoossens]

Thanks Tom and Jeff for the help!

The addEventCallback was exactly what I was looking for.