Localtofixedframe

<!--
  示例：局部坐标系
  说明：在指定点建立东-北-天坐标系，画出三根坐标轴并在局部坐标里放物体
  核心逻辑：Transforms.eastNorthUpToFixedFrame → Matrix4.multiplyByPoint → 局部坐标转世界坐标
  依赖：CesiumJS 1.121 · jsDelivr CDN
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>局部坐标系</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Widgets/widgets.css">
<style>
  html,body{height:100%;margin:0}
  body{background:#0e1116;color:#e6e8ec;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  #c{height:100%}
  .tip{position:absolute;left:12px;top:12px;z-index:5;
       background:rgba(23,28,35,.9);border:1px solid #2a313b;border-radius:6px;
       padding:8px 12px;font-size:12px;color:#a2a9b6;max-width:320px;line-height:1.6}

  .cesium-viewer-bottom .cesium-widget-credits,.cesium-viewer-animationContainer,
  .cesium-viewer-timelineContainer{display:none!important}
</style>
</head>
<body>
<div id="c"></div>
<div class="tip">红轴朝东、绿轴朝北、蓝轴朝天，都是从同一点长出来的。</div>
<script src="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Cesium.js"></script>
<script>
(function () {
  'use strict';

  var viewer = new Cesium.Viewer('c', {
    baseLayer: false,
    baseLayerPicker: false, geocoder: false, homeButton: false,
    sceneModePicker: false, navigationHelpButton: false,
    animation: false, timeline: false, fullscreenButton: false,
    infoBox: false, selectionIndicator: false
  });

  var scene = viewer.scene;
  scene.globe.baseColor = Cesium.Color.fromCssColorString('#1c2733');
  scene.backgroundColor = Cesium.Color.fromCssColorString('#0e1116');
  scene.skyBox.show = false;
  scene.sun.show = false;
  scene.moon.show = false;
  if (scene.skyAtmosphere) scene.skyAtmosphere.show = false;

  var origin = Cesium.Cartesian3.fromDegrees(116.3885, 39.9035, 0);
  var enu = Cesium.Transforms.eastNorthUpToFixedFrame(origin);

  function local(x, y, z) {
    return Cesium.Matrix4.multiplyByPoint(enu, new Cesium.Cartesian3(x, y, z), new Cesium.Cartesian3());
  }

  /* 三根轴：东红、北绿、天蓝，各 80 米 */
  viewer.entities.add({
    polyline: {
      positions: [local(0, 0, 0), local(80, 0, 0)],
      width: 5, material: Cesium.Color.RED
    }
  });
  viewer.entities.add({
    polyline: {
      positions: [local(0, 0, 0), local(0, 80, 0)],
      width: 5, material: Cesium.Color.LIME
    }
  });
  viewer.entities.add({
    polyline: {
      positions: [local(0, 0, 0), local(0, 0, 80)],
      width: 5, material: Cesium.Color.CYAN
    }
  });

  /* 在局部坐标 (35, 20, 10) 处放一个盒子 */
  var p = local(35, 20, 10);
  viewer.entities.add({
    position: p,
    box: {
      dimensions: new Cesium.Cartesian3(18, 18, 18),
      material: Cesium.Color.fromCssColorString('#d08a4e')
    }
  });
  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3908, 39.9012, 220),
    orientation: { heading: Cesium.Math.toRadians(-24), pitch: Cesium.Math.toRadians(-12), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>