How it works
Crafted a shaft or cogwheel in a mechanical crafter — you got EXP. Hit 150 EXP — you got a point. Spent a point to unlock an item — now it can be crafted anywhere: crafting table, press, mixer, saw, crushing wheels. Until you unlock it, machines simply won't run the recipe; items are returned, nothing is destroyed
The tree is a solar system. The main Create branch is the sun in the center, planets orbiting it are separate branches: fluids, logistics, contraptions. Click a planet and the camera flies along with it on its orbit. GUI - Button "I"
Configuration
Which items go where and what they cost is all JSON (data/createtree/createtree/skill_tree.json). Overridable with a datapack, /reload picks it up. Items fall into three categories: light (1 point), medium (2), complex (3). Cost and EXP reward can be set per item