在 Forge Viewer 中克隆对象

Question

I'm trying to clone an object in Forge Viewer. I have tried using THREE.js and creating a clone but it has different structure to the base object.

sceneBuilder = viewer.loadExtension("Autodesk.Viewing.SceneBuilder");
let modelBuilder = await sceneBuilder.addNewModel({
    conserveMemory: false,
    modelNameOverride: `Custom model`,
  });

let renderProxy = viewer.impl.getRenderProxy(viewer.model, fragId);
let geom = new THREE.Geometry();
let VE = Autodesk.Viewing.Private.VertexEnumerator;
VE.enumMeshVertices(renderProxy.geometry, (v: any, i: any) => {
    geom.vertices.push(new THREE.Vector3(v.x, v.y, v.z));
  });

  VE.enumMeshIndices(renderProxy.geometry, (a, b, c) => {
    geom.faces.push(new THREE.Face3(a, b, c));
  });
geom.computeFaceNormals();
let mesh = new THREE.Mesh(
    new THREE.BufferGeometry().fromGeometry(geom),
    renderProxy.material
  );
(mesh as any).dbId = dbId;
modelBuilder.addMesh(mesh);

I found that renderProxy is also THREE.Mesh , but when I tried let clone = renderProxy.clone(); modelBuilder.addMesh(clone) let clone = renderProxy.clone(); modelBuilder.addMesh(clone) , it doesn't work. Anyway to clone an object in Viewer?

Another thing, when I add a mesh by modelBuilder, I see that the created Object has added to Browser tree, but I still can't use Viewer functions with it (such as Viewer.select(dbId); Viewer.fitToView(); )

Answer 1

Cloning the renderProxy directly probably won't work as Forge Viewer basically returns the same THREE.Mesh instance whenever you request the proxy, just with different internals (for performance reasons).

The code snippet you provided (extracting vertices and faces from the proxy) is a safer choice. Is that snippet working as expected, or is it also causing issues?