The 3d helmet edit menu can be used to create or modify 3d helmet custom items. These are like regular custom helmets, but they can show a custom 3d model when worn. This is unfortunately the only armor piece that can have such a custom model (without Optifine). If you just started creating a new one, it should look like this:

3d helmets don't have any properties regular armor pieces don't have, so you can find information about all these properties in the armor edit menu. But, there are a couple of differences:

• 3d helmets must have a custom model (otherwise they don't really make sense). An example model will be shown at the bottom of this page.
• 3d helmets never have a leather color (because that would be useless since you can define the entire model anyway).
• The internal item type must be a hoe rather than a helmet. This is because of the resourcepack rules of minecraft: all items can show a custom model when being worn in the helmet slot, except helmets. (I didn't write this rule, but we will have to deal with it.) The plug-in will ensure that the 3d helmets can still be equipped like regular helmets, so you shouldn't notice anything about this in-game.

As promised, below is an example of a custom model:

{ "parent": "block/orientable", "textures": { "top": "blocks/furnace_top", "front": "customitems/NAME_OF_ONE_OF_YOUR_TEXTURES", "side": "blocks/furnace_side" } }

Make sure you replace the NAME_OF_ONE_OF_YOUR_TEXTURES with the name of one of your textures (doesn't have to be 'the texture' of the helmet you're editing.) This is a silly example model that will make the helmet a furnace, but with a different front texture.

This model is obviously not great, but a nice example. You should use a custom elements section in the model to create a nicer model.