[Oleksandr Kramer]

Hey,

Thanks for the detailed feature suggestion!
I really appreciate you taking the time to code a proof-of-concept – that shows genuine interest in improving the workflow.

Great news: this functionality already exists in Project Manager and has been available for over 10 years! 😊

You can assign materials to specific Material IDs using several methods:

Method 1: Direct viewport drag-and-drop Simply drag a material from PM directly onto an object in the viewport. PM will automatically detect and assign it to the appropriate slot. This works with regular objects and proxies (VRay/Corona).

Method 2: Face selection assignment Select the faces that need the material, then assign directly from PM – either by dragging or using the Assign button. Here’s a video demonstration:

https://www.youtube.com/watch?v=qQPckkcQvOw

Method 3: Multi-material slot replacement You can drag a material directly onto a specific slot in a Multi/Sub-Object material within the Material Editor to replace just that sub-material.

All these methods support both standard geometry and proxy objects, so you should be able to achieve exactly the workflow you described without needing a custom tool.

Give it a try and let me know if you encounter any issues or if there’s something specific that doesn’t work as expected!

Cheers