Hi! I'm not a coder but I'm very familiar with the Unreal Engine 4's visual scripting system which I used to create a tool that will help you to convert Rebrickable part lists to LDD user palettes,
This is how it looks right now:
Features:
One-click converting of Rebrickable CSV files to LDD user palettes
Features coming soon:
Converting decorations (prints) correctly
Converting rarely used colors correctly to colors available in LDD
Merging mold variations to bricks available in LDD
Support for old colors
Limitations/Disadvantages:
Since it's running on a video game engine, it's quite heavy in terms of file size (102 MB) and requires a modern PC
All bricks are placed at 0 0 0 so if you try to open the palette file, LDD will remove all but one brick.
Every part of a multi-part brick like power function components will have everything colored in the main color.
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Decide yourself if the relatively large file size is worth the time you may save in comparison to LDD manager's palette process (which is still a great tool!). Right now it only uses Rebrickable IDs for the LDD IDs but that is going to change when I get through each file and check it for mold variations and decorations. The colors IDs have been translated manually which is why I need feedback regarding the colors. Sometimes It wasn't easy to decide which color in LDD is which color on Rebrickable.
Is it worth continuing? Let me know what you think!