> ## Documentation Index
> Fetch the complete documentation index at: https://docs-unity.molca.id/llms.txt
> Use this file to discover all available pages before exploring further.
# GrabStep
> XR grab/release completion rules for XRGrabInteractable targets.
**File:** `Assets/_MolcaSDK/_VR/Scripts/Scenario/Steps/GrabStep.cs`\
**Base:** [Step](/core/step)
## When to use
Use `Grab Step` when a VR training scenario needs this specific interaction as a step in a sequence. Configure entirely in the Inspector — no code required.
## Role
Completes when the trainee grabs and/or releases an **`XRGrabInteractable`** according to serialized rules (auto-find interactable, required interactor, hold duration, optional position checks).
## Inspector
All behavior is driven by **`SerializeField`** definitions on the component — use the Inspector as the contract for designers.
## Code
Completion paths (from `selectEntered` / `selectExited` on **`grabInteractable`**):
* **`completeOnGrab`** without **`requireHoldDuration`** — **`CompleteGrab()`** runs on grab if **`ValidateGrabPosition()`** passes.
* **`requireHoldDuration`** — **`UpdateStep`** completes once hold time ≥ **`minGrabDuration`** and **`completeOnGrab`** is true.
* **`completeOnRelease`** — completes on release if not already completed.
* **`ForceComplete()`** — bypasses position checks after setting internal completed flag.
```csharp theme={null}
// Designer-driven: assign XRGrabInteractable + toggles in Inspector.
// Runtime override example — require left hand only:
using MolcaSDK.VR.Scenario;
using UnityEngine.XR.Interaction.Toolkit.Interactors;
public class GrabSetup : UnityEngine.MonoBehaviour
{
public GrabStep step;
public XRBaseInteractor leftHand;
private void OnEnable() => step.SetRequiredInteractor(leftHand);
}
```
## Troubleshooting
* **Console: no XRGrabInteractable found** — Assign **`grabInteractable`** or enable **`autoFindInteractable`** and put a **`XRGrabInteractable`** on this object or a child.
* **Grab registers but step never completes** — Check **`completeOnGrab`** vs **`completeOnRelease`**, **`requireHoldDuration`** / **`minGrabDuration`**, **interactor** filters (**`allowAnyInteractor`** / **`requiredInteractor`**), and **position** requirement (**`targetPosition`** + **`positionTolerance`**).
* **Wrong hand counts** — Set **`requireSpecificInteractor`** and assign the **`XRBaseInteractor`** for the intended controller.
## Related
* [Step (base class)](/core/step) — lifecycle and `Complete()`
* [VR player manager](/vr/vr-player-manager) — disable locomotion during precision grabs
* [VR inventory](/vr/vr-inventory-manager) — storing grabbed props
## Unity Editor
