iwsdk-grab

Testing & Quality

Grab an object in the WebXR scene using emulated controllers. Use when the user wants to pick up, move, or test grabbing an object. Supports OneHandGrabbable and TwoHandsGrabbable components which use proximity-based grip (squeeze button), not trigger.

QUICK START

How to use this skill

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Source SKILL.md: https://github.com/facebook/immersive-web-sdk/blob/HEAD/packages/starter-assets/claude-injections/skills/iwsdk-grab/SKILL.md

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Grab Object

Grab an object in the XR scene using the IWER emulated controllers. The workflow has a required core (steps 1-5) that must always execute, and optional extensions (steps 6-9) that depend on the user's intent.

User request is in $ARGUMENTS.

Required Core

These steps always execute in order. A grab cannot succeed without them.

Step 1: Enter XR

Check session status. If not in an active XR session, accept and enter.

xr_get_session_status → if not sessionActive → xr_accept_session

Step 2: Locate the target

Find the object by name in the scene hierarchy. Use scene_get_hierarchy and match against the name from $ARGUMENTS.

scene_get_hierarchy → find node matching the target name

If the object is not found, report the available named objects and stop.

Step 3: Get its transform

Get the object's world position using its UUID from step 2.

scene_get_object_transform(uuid) → use positionRelativeToXROrigin

Step 4: Animate controller to target

Animate the controller to the object's position. Default to "controller-right" unless the user specified left.

xr_animate_to({
  device: "controller-right",
  position: { x, y, z },
  duration: 0.5,
})

Step 5: Engage grip

OneHandGrabbable and TwoHandsGrabbable are proximity-based and use the squeeze/grip button (index 1), not the trigger.

xr_set_gamepad_state({
  device: "controller-right",
  buttons: [{ index: 1, value: 1 }],
})

The object is now grabbed. If the user only asked to grab (not move), stop here.

Optional Extensions

Apply these based on the user's request.

Step 6: Move to destination

If the user specified a destination position, animate the controller there. If no position was given but the user asked to "move" the object, animate it to in front of the headset.

To find "in front of headset": xr_get_transform({ "device": "headset" }) → place at (head.x, head.y - 0.2, head.z - 0.5) adjusted for head orientation.

xr_animate_to({
  device: "controller-right",
  position: { x, y, z },
  duration: 0.5,
})

Step 7: Release grip

Release the squeeze button to drop the object.

xr_set_gamepad_state({
  device: "controller-right",
  buttons: [{ index: 1, value: 0 }],
})

Step 8: Return controller

Animate the controller back to its resting position so it's not overlapping the dropped object.

xr_animate_to({
  device: "controller-right",
  position: { x: 0.2, y: 1.4, z: -0.3 },
  duration: 0.5,
})

Default resting positions: right (0.2, 1.4, -0.3), left (-0.2, 1.4, -0.3).

Step 9: Verify

Take a screenshot to confirm the result.

browser_screenshot

Notes

Never use xr_set_device_state to move controllers — it teleports instead of animating, which can break grab state.
Never use xr_select or trigger (button index 0) for grabs — OneHandGrabbable/TwoHandsGrabbable respond to squeeze (button index 1).
DistanceGrabbable is different — it uses ray-based selection, not proximity. This skill does not cover DistanceGrabbable.
If the object lacks a name in the hierarchy, suggest adding mesh.name = "MyObject" in code before createTransformEntity.