Arm Rotation

Vanilla Rotations

You can set the arm rotation for an item the player is holding! This is done by "wrapping" your model in an rpt:arm_transform model:

{
    "model": {
        "type": "rpt:arm_transform",
        "transform": "item",
        "model": {
            "type": "model",
            "model": "item/diamond_pickaxe"
        }
    }
}

In the example above, we specified the arm rotation used in the vanilla game when a player holds an item. Below is a list of vanilla rotations:

• empty - player is holding nothing
• item - player is holding an item that doesn't trigger rotations below
• block - player is raising a shield
• bow_and_arrow - player is drawing a bowstring
• throw_trident - player is winding up a trident throw
• crossbow_charge - player is charging a crossbow
• crossbow_hold - player is holding a charged crossbow
• spyglass - player is looking through a spyglass
• toot_horn - player is blowing a goat horn
• brush - player is using a brush
• spear - player is using a spear as a kinetic weapon (For 1.21.1 and higher)

In addition to vanilla rotations, you can define your own or modify some settings of vanilla ones:

Creating a Custom Rotation

{
    "model": {
        "type": "rpt:arm_transform",
        "transform": {
            // rotation along axes
            "x": 0, 
            "y": 0,
            "z": 0,
            "bob": true, // whether to apply "breathing" animation
            "swing": true, // whether to apply arm swinging animation when walking
            "attack": true, // whether to apply attack animation
            "type": "item" // type of animation from vanilla
        },
        "opposite" : { ... }, // Transformations for the opposite arm, if another item with rpt:arm_transform doesn't override it
        "model": { ... }
    }
}

Note

If you specify type in the record above, rotations along the axes will NOT be applied!

In addition to numbers, axes support expressions (see Mathematical Expressions for more details):

{
    "model": {
        "type": "rpt:arm_transform",
        "transform": {
            "x": "sin(time*0.75) * 45 - 90", // Player will swing their arm in front of their face
            "swing": false
        },
        "model": {
            "type": "model",
            "model": "item/bell"
        }
    }
}

RPT also provides some variables that can be used:

• time - game time in ticks
• hx/hy/hz - head rotation along axes
• useArm - the arm using the item: 1 if main, -1 if offhand
• swingArm - the arm performing the hit: 1 if right, -1 if left
• useTick - how many ticks the item has been in use
• holdArm - the arm holding the item: 1 if right, -1 if left

Please Note

Variables mentioned in Mathematical Expressions will not work in rpt:arm_transform!

---

Simple Example:

{
    "model": {
        "type": "rpt:arm_transform",
        "transform": {
            "x": "hx - 90",
            "y": "hy",
            "swing": false
        },
        "model": {
            "type": "model",
            "model": "item/diamond_pickaxe"
        }
    }
}