M
Hi @pyxelrigger thanks for reaching us, the main issue is to properly update you need to send the message MSG_DESCRIPTION_COMMAND and this is what the UI, it set the parameter then call this message.
But adding this call in the execute method of the python tag is not enough.
This message is processed by the constraint tag and add an Undo, and as said multiple time, this is not possible to add an undo in a threaded environment(see Python Tags - Shouldn't really they can change the scene? so this fail.
So the workaround is to not call the message during the scene execution of the scene but when the value is set in the user Data, so you react to a GUI interaction (main thread) so you are free to do what you want.
import c4d
#Welcome to the world of Python
def message(msgId, msgData):
# React to the change within the UI, since it came from the UI, this is executed in the Main Thread, so you can add Undo or Add Event
if msgId == c4d.MSG_DESCRIPTION_POSTSETPARAMETER:
# Check if its an User Data ID
if msgData['descid'].IsPartOf(c4d.DESCID_DYNAMICSUB):
# Checks if its the User Data ID 1 that changed
if msgData['descid'][-1].id == 1:
constraintTag = op.GetObject().GetTag(1019364)
# This will update the stuff and create an Undo
constraintTag.Message(c4d.MSG_DESCRIPTION_COMMAND, {"id": c4d.ID_CA_CONSTRAINT_TAG_PARENT_LOCALTRANFORM_UPDATEBUTTON})
c4d.EventAdd()
return True
def main():
option = op[c4d.ID_USERDATA,1]
constraintTag = op.GetObject().GetTag(1019364)
# Defines the new value (We could do it as well in the message method, but just to show you that Execute is called before)
constraintTag[c4d.ID_CA_CONSTRAINT_TAG_PARENT_LOCALTRANFORM_UPDATEBUTTON] = option + 1
test_scene.c4d
Cheers,
Maxime.
