Feature Request & Inquiry: Python Access to Named Selection Sets

[SttevanCJoga]

Python Access to Named Selection Sets

Summary

In 3ds Max, Named Selection Sets allow users to group objects or sub-objects for quick recall and organization. While these sets are accessible via the UI, current Python is limited.
Specifically:

• It is not possible to create a new selection set index via Python.
• There is no exposed API to store custom properties or metadata within a selection set for later retrieval.

Requested Features

1. Create Selection Set via Python
   Ability to define a new selection set index and populate it with a list of nodes or sub-objects.

2. Attach Custom Properties to Selection Sets
   Support for storing metadata (e.g. tags, user-defined attributes, timestamps) directly on the selection set object.

3. Query and Modify Selection Sets Programmatically
   Full read/write access to selection set contents and properties via Python.

Reference

For more details on Named Selection Sets, see the 3ds Max 2025 Help Documentation.

[wallworm]

Thanks for the suggestion. For the first request, this feature is already available. Here is a snippet to create named selection sets in Python:

from pymxs import runtime as rt
rt.NamedSelectionSetManager.AddNewNamedSelSet (rt.Selection, "My Set")

This will create a Named Selection Set from the currently selected nodes in the scene.

To query the selection set you can use:

rt.SelectionSets[1].name
rt.SelectionSets[1].count
rt.SelectionSets[1][0]

I did not figure out modifying the selection set yet.

Custom Properties do not seem possible as you noted.

Great ideas. We will look into helping you out.

[SttevanCJoga]

Thanks for the quick reply!

I managed to update the selection set using ReplaceNamedSelSetByName, although I'm not entirely sure if that's considered best practice in this context.

Here's a quick summary of the approach I used:

# Create a new selection set
pymxs.runtime.NamedSelectionSetManager.AddNewNamedSelSet([list_nodes], "Name")

# Update the list of nodes in an existing selection set
pymxs.runtime.NamedSelectionSetManager.ReplaceNamedSelSetByName([updated_list_nodes], "Name")

# Remove a selection set
pymxs.runtime.NamedSelectionSetManager.RemoveNamedSelSetByName("Name")

It would be great if we could also store metadata (e.g., custom attributes) directly within the selection set. That would make it much easier to track context or usage across different workflows.