# Cartwheel Video to Motion — API Reference

Model ID: `model_cartwheel-video-to-motion`

---

## Authentication

- **API_KEY** and **API_SECRET** are found in your [Scenario Project Settings](https://app.scenario.com/team&tab=api_keys) under API Keys.
- Set them as environment variables `SCENARIO_SDK_API_KEY` and `SCENARIO_SDK_API_SECRET` — both SDKs pick them up by default.
- For raw HTTP (cURL), use Basic Auth: `Authorization: Basic base64("<API_KEY>:<API_SECRET>")`.

### Install the SDK

- JavaScript / TypeScript: `npm install @scenario-labs/sdk`
- Python: `pip install scenario-sdk`

---

## Generate

**Endpoint:** `POST https://api.cloud.scenario.com/v1/generate/custom/model_cartwheel-video-to-motion`

### Parameters

| Parameter | Type | Required | Default | Description |
|-----------|------|----------|---------|-------------|
| `video` | assetId | yes | - | The video to copy movement from. The motion of the people in it is captured and applied to your character. Supports MP4, MOV, AVI, MKV, and WEBM. |
| `characterFile` | assetId | - | - | Optionally upload your own character. It's automatically prepared so the captured motion can be applied to it. |
| `numPeople` | number | - | `1` | The maximum number of people to track and capture from the video, up to four. |
| `facialCapture` | boolean | - | `false` | Also captures facial movement and expressions from the video, not just body motion. Available only with the Comic 4 pipeline. |
| `comicModel` | string | - | `comic4` | The version of Cartwheel's motion-capture engine to use. Comic 4 is the newest and supports facial capture. |
| `frameRate` | number | - | `24` | How many frames play per second. Higher values look smoother; 24 is standard for film, 30 or 60 for games. |
| `forward` | string | - | `Z` | Which direction the character is set to face. Match this to your 3D software's setup if the motion comes in turned the wrong way. |
| `up` | string | - | `Y` | Which direction counts as "up" for the character. Match this to your 3D software if the motion comes in oriented incorrectly. |
| `frameStepSize` | number | - | `1` | Controls how often a frame is recorded. Higher values produce fewer frames and a lighter file, with slightly less smooth motion. |
| `moveInPlace` | boolean | - | `false` | Keeps the character animating on the spot instead of traveling across the scene — useful for game engines where movement is handled separately. |
| `faceExpression` | string | - | `Default` | An optional facial expression to apply throughout the animation, such as Happy, Angry, or Surprised. |
| `keyframeCleaning` | string | - | `none` | Tidies up the animation data. Reduce and Simplify trim extra detail to make the file lighter and easier to edit by hand. |
| `skinHex` | string | - | - | An optional color for the character's skin, given as a hex code (for example, #BF916D). |
| `loop` | boolean | - | `false` | Makes the animation repeat seamlessly, so the end flows back into the start without a visible jump. |

### Example Requests

**cURL**

```bash
curl -X POST "https://api.cloud.scenario.com/v1/generate/custom/model_cartwheel-video-to-motion" \
  -H "Authorization: Basic $(echo -n '<API_KEY>:<API_SECRET>' | base64)" \
  -H "Content-Type: application/json" \
  --data-binary @- <<'EOF'
{
  "video": "<asset_id>",
  "numPeople": 1,
  "facialCapture": false,
  "comicModel": "comic4",
  "frameRate": 24,
  "forward": "Z",
  "up": "Y",
  "frameStepSize": 1,
  "moveInPlace": false,
  "faceExpression": "Default",
  "keyframeCleaning": "none",
  "loop": false
}
EOF
```

**Python**

```python
import os
from scenario_sdk import Scenario

client = Scenario(
    api_key=os.environ.get("SCENARIO_SDK_API_KEY"),
    api_secret=os.environ.get("SCENARIO_SDK_API_SECRET"),
)

body = {
    "video": "<asset_id>",
    "numPeople": 1,
    "facialCapture": False,
    "comicModel": "comic4",
    "frameRate": 24,
    "forward": "Z",
    "up": "Y",
    "frameStepSize": 1,
    "moveInPlace": False,
    "faceExpression": "Default",
    "keyframeCleaning": "none",
    "loop": False
}

response = client.generate.run_model(
    model_id="model_cartwheel-video-to-motion",
    body=body,
)
print(response)
```

**JavaScript**

```javascript
import Scenario from "@scenario-labs/sdk";

const client = new Scenario({
  apiKey: process.env["SCENARIO_SDK_API_KEY"],
  apiSecret: process.env["SCENARIO_SDK_API_SECRET"],
});

const body = {
  "video": "<asset_id>",
  "numPeople": 1,
  "facialCapture": false,
  "comicModel": "comic4",
  "frameRate": 24,
  "forward": "Z",
  "up": "Y",
  "frameStepSize": 1,
  "moveInPlace": false,
  "faceExpression": "Default",
  "keyframeCleaning": "none",
  "loop": false
};

const response = await client.generate.runModel("model_cartwheel-video-to-motion", { body });
console.info(response);
```

---

## Retrieve Results

After submitting a generation request, you receive a `jobId`. Poll the job until `job.status` is `"success"`. The generated asset IDs are in `job.metadata.assetIds`.

**Endpoint:** `GET https://api.cloud.scenario.com/v1/jobs/{jobId}`

### Example Requests

**cURL**

```bash
curl -X GET "https://api.cloud.scenario.com/v1/jobs/<JOB_ID>" \
  -H "Authorization: Basic $(echo -n '<API_KEY>:<API_SECRET>' | base64)"
```

**Python**

```python
job = client.jobs.retrieve(job_id="<JOB_ID>")
print(job.status)
print(job.metadata.asset_ids)
```

**JavaScript**

```javascript
// Option 1 — wait on the response from runModel using the SDK helper
const completed = await response.job.wait();
console.info(completed.status);
console.info(completed.metadata?.assetIds);

// Option 2 — retrieve a job by its ID
const job = await client.jobs.retrieve("<JOB_ID>");
console.info(job.status);
console.info(job.metadata?.assetIds);
```

**Example response:**

```json
{
  "job": {
    "jobId": "job_abc123",
    "status": "success",
    "metadata": {
      "assetIds": [
        "asset_abc123"
      ]
    }
  }
}
```

> **Important:** Generated asset URLs are **temporary** and expire after a short period. Download and store any images you wish to keep before the URL expires. More info: [Content Delivery Network (CDN)](https://docs.scenario.com/get-started/documentation/content-delivery-network-cdn).

---

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