Omni Dev - The In-Game Developer Toolkit

Omni Dev ist a utility mod designed by developers, for developers.
Whether you are making a massiv mod, a coustom map, or just want to test vanilla mechanics.
All generated .nbt an .json files are automatically exported to your saves/YOUR_WORLD/generated/omnidev/ folder.

The Workflow
With Omni Dev, creating a fully functional dungeon is as easy as:

Build your structure and place your chests.
Generate custom loot using the in-game GUI (/dev_lootgen)
Assign the saved loot table to a chest just by looking at it (/dev_setloot)
Select your building using the Omni Dev Wand.
Save it! You now have a completet .nbt structure with fully working, randomzed loot tables inside.

Commands

Structure Tools:

/dev_wand - Gives you the selection stick to mark Position 1 and Position 2.
/dev_pos1 & /dev_pos2 - Manualy set your selection boundaries.
/dev_save [name] - Saves your selceted area as an .nbt structure file.
/dev_spawn [structure_id] - Spawns any structure in the game at your location (supports Vanilla and all Modded structures).
/dev_clear - undoes/deletes the last structure you spawnt with /dev_spawn.

Loot Table Tools:

/dev_lootgen [name] - Opens a GUI Visually drag and drop items into the interface to generate a fully working .json loot table, completely without writing code.
/dev_setloot [loot_table_name] - Look at any container (chest, barrel,dispenser) to permanently inject an existing loot table into it before saving your structure.

Loot Simulation:

/simulate_loot [loot_table] [runs] [enchantment_level] [player_kill] Instantly test drop rates an percentages by simulating thousands of chest openings or mob kills dircetly in you chat! The enchantment_level perfectly mimics Fortune or Looting.

Examples

/simulate_loot minecraft:entities/sheep/pink 1000 3 true (Simulates 1000 pink sheep kills with Looting 3 by a player)
/simulate_loot minecraft:chests/desert_pyramid 1000 (Simulates opening 1000 desert pyramid chests)
/simulate_loot minecraft:blocks/diamond_ore 1000 3 false (Simulates mining 1000 diamond ores with Fortune 3)