{
  "taskId": "expansion-050",
  "slug": "single-light-shadow-direction",
  "language": "zh",
  "mode": "image-to-video",
  "modelId": "MiniMax-H3",
  "evidenceClass": "original-practice-method-not-model-tested",
  "input": {
    "path": "/learning-assets/pseo-expansion70-20261014/single-light-shadow-direction/first-frame.png",
    "editableSource": "/learning-assets/pseo-expansion70-20261014/single-light-shadow-direction/first-frame.svg",
    "role": "first_frame",
    "sourceType": "original-illustration"
  },
  "intent": {
    "cluster": "Historical lighting, camera and image-to-video prompt family",
    "historicalQueries": [
      "minimax h3 image to video reference to video prompt setting only background camera lighting",
      "minimax h3 image to video",
      "minimax h3提示词模板"
    ],
    "evidenceRef": "docs/research/pseo-keyword-gap-2026-10-05/evidence/bing-live-keywords.csv",
    "distinctValue": "A single-light movement study on a fixed matte arch block, linking one key-light shift to one attached floor shadow while keeping camera and object still.",
    "existingOwnerBoundary": [
      {
        "path": "/blog/camera-movement-prompts",
        "difference": "This exercise holds the camera fixed and moves only one described light; it supplies a shadow scene rather than another camera vocabulary article."
      },
      {
        "path": "/blog/product-shape-consistency-video",
        "difference": "The supplied matte block isolates shadow direction and contact anchoring rather than teaching general product structure preservation."
      }
    ],
    "demandClass": "historical-parent-query; exact long-tail demand unmeasured"
  },
  "title": "单灯影向：物体固定，检查一条投影",
  "description": "只让一盏柔光主灯向上方中央小幅移动，观察静物投影是否连续响应，保持接触端不脱离。",
  "goal": "规划一次小幅单灯移动，检查由此改变且连接底部的影子。原创打光插画是定性练习，不是H3实测重打光，也不是标定测光布置。",
  "preparation": [
    "首帧选择哑光物体，平面上有一条可读投影。配套拱形块由左上照明，投影朝右下。",
    "保留底部与地面缝线，便于区分影形变化和物体在桌面滑动。",
    "只让柔光主灯略移向上方中央，不绕物一圈；首轮不加轮廓灯、机位旋转或背景变色。",
    "验收方向与连续性即可；精确影长、照度和反射率需要测量或渲染，不能由本提示词证明。"
  ],
  "prompt": "从上传的哑光拱形块图开始。物体和摄影机完全固定，底部保持原有台面接触。只有一盏柔光主灯，起始从左上照入。这盏灯缓慢向上方中央移动一小段后停住。唯一投影平滑响应，从右下略转向下方中央，同时稍微缩短，接触端始终连在块体底部。受光面与暗面随灯位变化柔和改变。拱口和哑光表面保持不变。不出现第二条投影，不移动物体，不运镜，不发光，不增加光源。",
  "steps": [
    {
      "title": "读出起始灯影对应",
      "body": "先确认左上亮面与右下投影在输入里一致。多条冲突投影的素材无法隔离单灯变化。"
    },
    {
      "title": "只移动主灯",
      "body": "写成物体和机位固定，主灯向上方中央小幅移动。不要同时要求转动物体揭示，它会改变影子变化的原因。"
    },
    {
      "title": "先追踪影子接触端",
      "body": "先看影子与底部相接的位置，再看远端。接触端应锚定，长度和方向可变，不能变成独立漂走的暗片。"
    },
    {
      "title": "核对表面明暗",
      "body": "对比起止的物面明暗和投影。两者响应方向冲突或新增影子时，先简化灯位变化，再检查同一关系。"
    }
  ],
  "acceptance": [
    "块体与台面接触位置固定。",
    "拱形开口形状不变且始终敞开。",
    "只有一条可辨投影，没有新增冲突影子。",
    "投影接触端始终连接块体底部。",
    "方向由右下平滑略转向下方中央。",
    "影子稍微缩短，没有瞬移或穿过块体。",
    "物面明暗连贯响应，最终灯影状态静止保持。"
  ],
  "troubleshooting": [
    {
      "symptom": "影子从底部漂走",
      "change": "只修改影子附着句，明确底部接触，保留同样灯位路线。"
    },
    {
      "symptom": "多出第二条硬影",
      "change": "只把照明改成唯一柔光主灯、没有额外光源，保留小幅移动。"
    },
    {
      "symptom": "物体旋转代替灯位移动",
      "change": "只把物体相对地缝朝向写成固定，去掉转台揭示的措辞。"
    },
    {
      "symptom": "影子突然跳到另一侧",
      "change": "只减小主灯行程，让试验保持小幅方向变化，再看过渡。"
    }
  ],
  "ending": "灯位停住后结束，拱块固定且只有一条相连投影。记录定性方向检查，不声称完成测量级重打光。",
  "assetCaption": "原创哑光拱块插画，单一左上光与右下投影明确；这是概念输入，不是H3照明测试结果。"
}