minecraft-kajetans-mod/src/main/resources/assets/km/blockstates/cauldron_birch.json

{
    "variants": {
        "normal": { "model": "km:cauldron/birch/cauldron_empty" },
        "level=0": { "model": "km:cauldron/birch/cauldron_empty" },
        "level=1": { "model": "km:cauldron/birch/cauldron_level1" },
        "level=2": { "model": "km:cauldron/birch/cauldron_level2" },
        "level=3": { "model": "km:cauldron/birch/cauldron_level3" }
    }
}