# RTK Motion BVH Motion Capture File Download

> RTK Motion BVH Motion Capture File Download is a paid API for AI agents from api.rtkmotion.io, paid per call via x402, $10/call, status unknown (last checked 2026-10-10).

Retrieves a BVH-format 4D motion-capture file (full skeleton, 60fps) for a specified subject, with a signed download URL and provenance metadata.

## Facts

- Endpoint: GET https://api.rtkmotion.io/paid/bvh?utm_source=zero.xyz
- Price: $10/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rtk-motion-bvh-motion-capture-file-download-f5f42041
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yPAH2Ch7Jrp0s7PTt4gEZ

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability rtk-motion-bvh-motion-capture-file-download-f5f42041
```

Example prompt: Fetch the RTK Motion BVH file for subject_1 — I need the full 60fps skeleton capture with the signed download URL so I can import it into my robotics pipeline.

## When to prefer this

Use this endpoint when you need a full, authenticated BVH skeleton motion-capture file at 60fps for a specific subject, particularly for robotics imitation learning, biomechanics research, or animation pipelines that require verified data provenance via ECDSA signature. Prefer this over excerpt or preview endpoints when you need the complete frame sequence rather than a sample.

## Known failure modes

- Payment not completed — 402 response requiring x402 micropayment before data is released
- Invalid subject parameter — only 'subject_1' and 'subject_2' are accepted values
- Download URL expiry — if the returned URL is not redeemed within 900 seconds, a re-purchase is required
- Network timeout on large BVH file (~592 KB) during download
- Signature verification failure if provenance hash does not match downloaded file content

## How this service works

RTK Motion — 4D motion-capture data and AI agents for robotics and human-movement intelligence.

## Output

Returns a JSON object containing: a time-limited download_url (expires in 900 seconds) pointing to the full BVH file, a BVH excerpt preview (first 40 lines), frame count (e.g. 1215), FPS (60), joint count (56), lesson label (e.g. BJJ/Training/KimuraFromSideControl/Lesson001), SHA256 hash, subject ID, byte size, and an ECDSA provenance signature signed by a known Ethereum address. The full BVH file must be downloaded before the URL expires.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "subject": {
       "type": "string",
       "description": "Subject to retrieve: 'subject_1' (default) or 'subject_2'."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "fps": 60,
  "bytes": 592418,
  "domain": "4D Motion Capture",
  "format": "BVH",
  "frames": 1215,
  "joints": 56,
  "lesson": "BJJ/Training/KimuraFromSideControl/Lesson001",
  "sha256": "…",
  "subject": "subject_1",
  "next_step": {
   "note": "bvh_excerpt_preview_only is the first 40 lines, NOT the purchased product. Redeem download_url before expiry or re-purchase is required.",
   "action": "GET download_url to retrieve the full BVH file",
   "required": true,
   "expires_in_seconds": 900
  },
  "provenance": {
   "algorithm": "secp256k1-ECDSA",
   "signed_by": "0x6C11F8a21f7ca922F483Ed21C3b6c2d9B305B10C"
  },
  "download_url": "https://api.rtkmotion.io/data/…",
  "bvh_excerpt_provenance": "HIERARCHY\nROOT Hips\n{..."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rtk-motion-bvh-motion-capture-file-download-f5f42041/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.rtkmotion.io](https://www.zero.xyz/host/api.rtkmotion.io/llms.txt)