Question

我正在尝试根据BCF文件中的BIM主题可视化数据正确初始化Autodesk Forge 3D查看器。

我已将3D模型（IFC）上传到Autodesk API，它已经过处理，可以使用Autodesk Forge 3D查看器成功地可视化/导航模型。

我在Nemetschek SOLIBRI中使用了相同的3D模型（IFC）创建主题，并使用BIM BCF 2.1标准将其导出（请参见https://github.com/buildingSMART/BCF-XML）。

VisualizationInfo的XML数据：

<PerspectiveCamera>
  <CameraViewPoint>
      <X>2.803843040759871</X>
      <Y>14.568845808384443</Y>
      <Z>0.8249055320631105</Z>
  </CameraViewPoint>
  <CameraDirection>
      <X>0.4898262677194313</X>
      <Y>-0.8652456579090667</Y>
      <Z>0.1068652371988122</Z>
  </CameraDirection>
  <CameraUpVector>
      <X>-0.05264688190667085</X>
      <Y>0.09299722978166312</Y>
      <Z>0.9942735142195238</Z>
  </CameraUpVector>
  <FieldOfView>60.0</FieldOfView>
</PerspectiveCamera>

我试图在Autodesk Forge 3D查看器中设置相同的摄像机/视图：

viewer.restoreState(JSON.parse(`{
  "viewport": {
    "eye": [2.803843040759871, 14.568845808384443, 0.8249055320631105],
    "target": [0.4898262677194313, -0.8652456579090667, 0.1068652371988122],
    "up": [-0.05264688190667085, 0.09299722978166312, 0.9942735142195238],
    "projection": "perspective",
    "isOrthographic": false,
    "fieldOfView": 60.0
  }
}`));

结果：一种Forge 3D查看器相机视图，它与SOLIBRI中看到的视图不匹配，也与BCF文件中另存为snapshot-png的视图不匹配。

也许SOLIBRI中的IFC模型和Autodesk处理的IFC模型具有不同的坐标系，或者可能是什么错误？

Answer 1

CameraDirection值不是Forge查看器的目标参数。您必须使用以下公式自己计算。

{Target} = {CameraViewPoint} + {CameraDirection} * {CurrentFocalLength}

问题视图的完整摄像机映射为：

var lengthScale = 1000; //! Use viwer.model.getUnitString(), the model I loaded is in `mm`, and BCF camera definition is in `m`
var eye = new THREE.Vector3( 2.803843040759871 * lengthScale, 14.568845808384443 * lengthScale, 0.8249055320631105 * lengthScale );
var sightVec = new THREE.Vector3( 0.4898262677194313, -0.8652456579090667,  0.1068652371988122 ).multiplyScalar( viewer.navigation.getFocalLength() );
var target = eye.clone().add( sightVec )
var up = new THREE.Vector3( -0.05264688190667085, 0.09299722978166312, 0.9942735142195238 );

//Since Forge Viewer will apply a global offset to the whole model
var offsetMatrix = viewer.model.getData().placementWithOffset;
var offsetEye = eye.applyMatrix4(offsetMatrix); 
var offsetTarget = target.applyMatrix4(offsetMatrix);
var fov = 60;

var cameraView = {
    aspect: viewer.getCamera().aspect,
    isPerspective: true,
    fov: fov,
    position: offsetEye,
    target: offsetTarget,
    up: up,
    orthoScale: 1
};

viwer.impl.setViewFromCamera( cameraView );

享受吧！

如何从BIM BCF主题视点正确初始化Autodesk Forge 3D查看器？

1 个答案: