A pack for adding and posing player models in Minecraft Java Edition.

In the save folder of whichever world you want to use this pack in, paste player_models_dp into the world's datapacks folder. You will also need to paste player_models_rp into your resourcepacks folder and enable the resource pack. When you have joined your world, run /tag @s add player_models. This command will put items in your hotbar which will act as the interface for the data pack. The "Exit" item that will appear in your ninth hotbar slot can be used to free your hotbar, and you can run /tag @s add player_models again at any time to re-enter the interface.

The pack lets you spawn in new player models, change which skin they wear, and pose the player models to your liking. Clicking the "Position [+]" item from the home menu of your hotbar interface lets you move a player model in either 2 block, 1/2 block, or 1/16 block increments in any direction. Additionally, clicking the "Rotation [+]" item lets you rotate the whole player model around its vertical axis. The "Pose [+]" item opens a menu in which you can choose to rotate any of the player model's bones—its head, its body, its arms, or its legs. These bones can each be rotated on all three axes in increments of 90 degrees, 15 degrees, or 2.5 degrees.

This section might be difficult to understand... sorry in advance. In order to upload your own skin that can be flipped to via the "Previous Skin" and "Next Skin" items, you need to directly edit the resource pack, player_models_rp. I recommend using a text editor like VSCode that supports JSON syntax highlighting because it will make your life easier.

First, download the image file of whichever skin you want to upload to the pack. You can do this easily for any player by searching their name on NameMC, clicking on their skin under the "Skins" section of their profile, and then clicking the "Download" button. I recommend renaming the skin file to the IGN of whoever the skin belongs to. Let's say that the skin file is now called ign.png. Now, open the resouce pack's folder player_models_rp. Navigate to assets/player_models/textures/skins and drop your skin file into that folder.

Next, you need to create the model files for a player with your skin applied to it. In assets/player_models/models/players, you'll see two folders called steve_skin and alex_skin. If your skin uses the Steve player model, make a copy of the steve_skin folder and rename that folder to your IGN. If your skin uses the Alex model, then copy the alex_skin folder and rename it to your IGN. Make sure that the new folder is still in assets/player_models/models/players, and I'll say that the new folder is called ign. Now, inside ign, there will be 6 files: body.json, head.json, left_arm.json, left_leg.json, right_arm.json, and right_leg.json. Open each of these files, and change the text player_models:skins/steve_skin or player_models:skins/alex_skin to player_models:skins/ign (whatever you renamed skin file to be). Note: if you're using VSCode, you can right-click on the ign folder, select "Find in folder..." from the dropdown menu, and replace steve_skin or alex_skin (whichever is applicable) with ign. Ctrl+Alt+Enter is the hotkey for "replace all".

Lastly, you need to link the models that you just made to the "custom model data" of a melon slice. In assets/minecraft/models/item, there is a file called melon_slice.json. Open that file, and you'll see three chunks of six lines of code. Copy one of those chunks, and paste it below the last chunk in the file. Then, for each line in the chunk, replace the player name of the skin you copied with ign (whatever you named your folder in assets/player_models/models/players). For example, player_models:players/steve_skin/head would become player_models:players/ign/head. Finally, you need to change the "custom_model_data" values in the new chunk so that the numbers continue to increase by 1 for each line. Your file should now look like:

{
  "parent": "minecraft:item/generated",
  "textures": {
    "layer0": "minecraft:item/melon_slice"
  },
  "overrides": [
    { "predicate": {"custom_model_data": 1}, "model": "player_models:players/steve_skin/head" },
    { "predicate": {"custom_model_data": 2}, "model": "player_models:players/steve_skin/body" },
    { "predicate": {"custom_model_data": 3}, "model": "player_models:players/steve_skin/right_arm" },
    { "predicate": {"custom_model_data": 4}, "model": "player_models:players/steve_skin/left_arm" },
    { "predicate": {"custom_model_data": 5}, "model": "player_models:players/steve_skin/right_leg" },
    { "predicate": {"custom_model_data": 6}, "model": "player_models:players/steve_skin/left_leg" },

    { "predicate": {"custom_model_data": 7}, "model": "player_models:players/alex_skin/head" },
    { "predicate": {"custom_model_data": 8}, "model": "player_models:players/alex_skin/body" },
    { "predicate": {"custom_model_data": 9}, "model": "player_models:players/alex_skin/right_arm" },
    { "predicate": {"custom_model_data": 10}, "model": "player_models:players/alex_skin/left_arm" },
    { "predicate": {"custom_model_data": 11}, "model": "player_models:players/alex_skin/right_leg" },
    { "predicate": {"custom_model_data": 12}, "model": "player_models:players/alex_skin/left_leg" },

    { "predicate": {"custom_model_data": 13}, "model": "player_models:players/melonbp/head" },
    { "predicate": {"custom_model_data": 14}, "model": "player_models:players/melonbp/body" },
    { "predicate": {"custom_model_data": 15}, "model": "player_models:players/melonbp/right_arm" },
    { "predicate": {"custom_model_data": 16}, "model": "player_models:players/melonbp/left_arm" },
    { "predicate": {"custom_model_data": 17}, "model": "player_models:players/melonbp/right_leg" },
    { "predicate": {"custom_model_data": 18}, "model": "player_models:players/melonbp/left_leg" }
    
    { "predicate": {"custom_model_data": 19}, "model": "player_models:players/ign/head" },
    { "predicate": {"custom_model_data": 20}, "model": "player_models:players/ign/body" },
    { "predicate": {"custom_model_data": 21}, "model": "player_models:players/ign/right_arm" },
    { "predicate": {"custom_model_data": 22}, "model": "player_models:players/ign/left_arm" },
    { "predicate": {"custom_model_data": 23}, "model": "player_models:players/ign/right_leg" },
    { "predicate": {"custom_model_data": 24}, "model": "player_models:players/ign/left_leg" }
  ]
}

Hopefully, your skin is now a player model in the resource pack. I added my own skin in the resource pack in case you want to reference it as a worked example. If your skin renders in-game as missing textures, double check that you haven't misspelled your ign anywhere and that your files and folders are in the right place.