Q100372: How to rename input and output ports with Python for clearer connections

Bradley Webster

Updated : November 07, 2023 16:03

Created : January 31, 2018 05:33

SUMMARY

When setting up nodes with multiple inputs (such as Merge, Switch or Global State Variables nodes), it can be quite tedious to manually rename each connection port to clarify the connection purpose. To automate the process, you can create a custom Shelf Item or SuperTool with Python that handles the renaming. This article explains how this can be achieved.

MORE INFORMATION

An example script that loops through each selected node’s input ports and renames them to a specific value, is included and explained below.

This can be tested within Katana using, for example, a Merge or VariableSwitch node.

EXAMPLE SCRIPT

# Grab all currently selected nodes
selectedNodes = NodegraphAPI.GetAllSelectedNodes()

# Loop through each selected node
for node in selectedNodes:
    # Get all the import ports within the node
    inputPorts = node.getInputPorts()
    # Loop through each port within the node
    for inputs in inputPorts:
        index = inputs.getIndex()
        name = node.getInputPortByIndex(index).getName()
        # Name each port 'Shot' plus their indexed location
        node.renameInputPort(name,('Shot'+repr(index+1)))

USING THE SCRIPT

Within Katana, the script can be tested by simply creating a Merge or VariableSwitch node and adding multiple input ports to it (click on the large arrow on the node to add an input port):

Pasting/executing the above script into the Python tab while the node is selected should rename the default input ports to something like: 

You can also test the above script as a custom Shelf Item by downloading the attached 'renameInputPorts.py' file and placing it in the user's home area '.katana/Shelves/' directory, under a Shelf folder name.

For example:

Windows: C:\Users\username\.katana\Shelves\RenameShelf\renameInputPorts.py
Linux: /home/username/.katana/Shelves/RenameShelf/renameInputPorts.py


This setup is the basis for a custom Shelf or SuperTool. From here, you could additionally add a popup widget that will allow you to rename each port or you can include the code as part of the SuperTool node itself.

For more information on setting up connections, creating Shelf Items and SuperTools, please check the Katana User Guide and Katana Developer Guide using the links below:

Python connecting nodes: Katana Developer Guide - Working with Nodes - Connecting Nodes
Shelf scripts: Katana User Guide - Scripting and Programming in Katana - Shelf Item Scripts
SuperTools: Katana User Guide - Groups, Macros, and Super Tools - SuperTools

SCRIPT EXPLANATION

selectedNodes = NodegraphAPI.GetAllSelectedNodes()

Using the NodegraphAPI you first find the target nodes to apply the script logic to. This can be done in two ways: either by specifying the nodes by their name or by querying for currently selected nodes. The above line finds and stores the list of currently selected node objects as "selectedNodes." 

for node in selectedNodes:
    inputPorts = node.getInputPorts()

Once you have the list of node objects, you can iterate through each via a for loop and call the getInputPorts() function which obtains all the input ports of the nodes.

for inputs in inputPorts:         
    index = inputs.getIndex()

Now that you have the ports of each node, you can set it to loop through the individual ports either by their name or via their indexed location. The above line finds their index location using the getIndex() function. 

name = node.getInputPortByIndex(index).getName()
node.renameInputPort(name,('Shot'+repr(index+1))) 

The above lines retrieve the current name of the node port and rename it to Shot followed by the index of that port. The final name looks like Shot1, Shot2, Shot3 depending on how many ports a node has. 

ATTACHMENTS