Blender background jobs

Use for job.* when an approved output root exists. A submission saves a versioned source snapshot first; the child Blender process may write only inside its job directory. The foreground may continue editing, but the job remains bound to the submitted snapshot.

Route by kind: EXPORT and RENDER_STILL also use blender-render-compositing; BAKE_POINT_CACHES also uses blender-simulation. Use RENDER_ANIMATION_FRAMES for a persistent PNG or multilayer EXR sequence. Use COMPOSE_VIDEO only after its source FrameSequenceReceipt has complete frame hashes; it produces a separate H.264 receipt without rerendering Blender.

Query status until a terminal receipt and keep the job ID, snapshot hash, manifest hash, and artifact receipt together. Cancellation terminates only the child task. job.recover may mark a lost task interrupted but never restarts it. Resume only after an explicit job.resume; verified frames remain untouched while missing or hash-invalid frames are replaced. A background receipt does not approve external upload, publishing, payment, or Video Factory orchestration.

什么时候使用（When to Use）

渲染、导出或缓存烘焙会阻塞前台，或者任务要求断点恢复和逐帧校验时使用。快速且必须立即观察结果的操作继续走对应前台技能。

输入与前置条件（Prerequisites）

• 已提交的 sceneRevision + snapshotId、批准的输出根目录和不可覆盖约束。
• 明确任务类型、帧范围、格式、超时和磁盘预算，并确认子进程可读取依赖素材。

执行流程（Workflow）

Step 1. 按产物选择作业类型并保存不可变快照。 Step 2. 提交作业，记录 job ID、快照哈希、清单哈希和输出目录。 Step 3. 轮询至终态；中断后先恢复检查，只有显式 job.resume 才继续。 Step 4. 仅替换缺失或哈希错误的帧，最后生成终态收据与产物清单。

验证与交付证据（Validation）

核对终态、退出码、快照哈希、帧区间、逐帧哈希、文件大小和媒体探测结果。视频合成还需证明输入序列完整以及时长、帧率、尺寸符合约定。

Rules 与能力边界（不适用场景）

后台成功不等于画面质量已接受，也不授权上传、发布或付费服务。作业不得写出批准目录，不自动重启未知状态任务。

Gotchas（常见问题与恢复）

• 子进程消失：标记 interrupted，保留日志与已验证帧。
• 单帧损坏：按哈希定位并只重做该帧。
• 磁盘不足或路径越界：立即停止并报告实际路径与空间需求。