I finished a Python program that (re)creates a lif file from a folder structure. So basically you can first use LIFExtractor.py (by JrMasterModelBuilder) to extract db.lif, then add mods and new bricks and afterwards repack the modified db folder with this tool (LIFCreator.py). It is tested on macOS 10.14.6 and Windows 10. It worked with LDD 4.3.11, bluerender 0.6 (that is the new added bricks where loaded and rendered) and of course I also tested it with JrMasterModelBuilders LIFExtractor.py (packing with this tool, unpacking with JrMasterModelBuilders LIFExtractor and vice versa). Still I don't guarantee any functionality and suggest you to keep backups (especially of the original db.lif). WARNING: You accept full responsibility of using it yourself ! https://github.com/sttng/LIF-Creator How to: ./LIFCreator.py /Users/your_user_name/Library/Application\ Support/LEGO\ Company/LEGO\ Digital\ Designer/db On Windows type the following into the command-line LIFCreator.exe "C:\Users\<YOUR USER>\AppData\Roaming\LEGO Company\LEGO Digital Designer\db" Below a bluerender test (the leaves are a new custom part):