> ## 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.
# StepBridge and SequenceBridge
> Cross-sequence coordination steps.
**Files:**
* `Assets/_MolcaSDK/_VR/Scripts/Scenario/Steps/StepBridge.cs`
* `Assets/_MolcaSDK/_VR/Scripts/Scenario/Steps/SequenceBridge.cs`
## When to use
Use `Step Bridge` when a VR training scenario needs this specific interaction as a step in a sequence. Configure entirely in the Inspector — no code required.
## Role
Thin **`MonoBehaviour`** helpers (not **`Step`** subclasses) that **resolve** remote objects via **`SceneObjectReference`** after **`Start`**:
* **`StepBridge`** — **`CompleteStep()`** / **`ResetStep()`** on a resolved **`Step`**.
* **`SequenceBridge`** — **`StartSequence`**, **`StopSequence`**, **`PauseSequence`**, **`ResumeSequence`**, **`RestartSequence`**, **`CompleteCurrentStep()`** on a **`SequenceController`**.
Use for UI buttons, triggers, or other prefabs that must drive a step or sequence elsewhere in the scene.
## Code
```csharp theme={null}
// Wire a Canvas button to StepBridge.CompleteStep() after resolving stepRef.
// SequenceBridge — external control:
using UnityEngine;
public class HubMenu : MonoBehaviour
{
public SequenceBridge training;
public void Begin() => training.StartSequence();
public void Abort() => training.StopSequence();
}
```
Both rely on async **`ResolveAsync`** in **`Start`** — avoid calling **`CompleteStep()`** before resolution finishes (add a short delay or guard).
## Troubleshooting
* **Null Step / SequenceController** — **`SceneObjectReference`** not assigned, target missing **`ReferenceableComponent`**, or **`Start`** not run yet.
* **No effect** — Confirm the resolved **Step** is the active one in your [SequenceController](/core/sequence-controller) graph.
* **`StepBridge` vs Sequence** — This script **does not** participate in the sequence as a **Step**; it only invokes methods on an existing step instance.
## Related
* [Reference system](/core/reference-system)
* [Sequence controller](/core/sequence-controller)
* [Step (base class)](/core/step)
## Unity Editor
