「翻译」在Forge Viewer上实作简易的模型版本比较

摘要：现在让我们修改这个示例让他可以展示两个同项目但不同版号的模型及。示例执行结果如下这边是这个比较模型的括展代码英文原文

熟悉 BIM360 Team 的朋友可能知道他有一个很牛的模型文档版本比较的功能，但如果模型是放在 Google 云盘或是百度云盘上有可能做到吗？

Autodesk Forge 团队先前写了一个从 Google 云盘的转档示例，这个示例会从 Google 云盘里下载模型文档到你的服务器上，在将它上传到 Forge Data Management 服务上进行转档，同时在转档完成后在浏览器上展示结果。

现在让我们修改这个示例让他可以展示两个同项目但不同版号的 Revit 模型（model A 及 model B）。在 Forge Viewer 里，每个 Revit 构件都会对应到一个 dbId，而这个 dbId 也会对应到一个 Reivt 唯一码（Unique GUID），这个唯一码也是 Forge Viewer 的外部编码（Extenal Id），所以只要在 model A 及 model B 里比对两者间有没有不存在的 Extenal Id，以及比对同一个 External Id 的构件属性里有没有被新增、修改及删除的参数，根据这个思路我们可以将没有修改的构件隐藏起来，有异动的构件以绿色（新增的）、红色（删除的）及橘色（有修改的）来上色，就可以在 Forge Viewer 上做出简单的模型比较功能，原代码可以参考这里，示例可造访这里。

示例执行结果如下：

这边是这个比较模型的括展代码：

</>复制代码 
function VersionChanges(viewer, options) {
  Autodesk.Viewing.Extension.call(this, viewer, options);
}
VersionChanges.prototype = Object.create(Autodesk.Viewing.Extension.prototype);
VersionChanges.prototype.constructor = VersionChanges;
VersionChanges.prototype.load = function () {
  var modelA = this.options.modelA;
  var modelB = this.options.modelB;
  var removed = {};
  var added = {};
  var modified = {};
  var red = new THREE.Vector4(1, 0, 0, 1);
  var green = new THREE.Vector4(0, 0.5, 0, 1);
  var orange = new THREE.Vector4(1, 0.6, 0.2, 1);
  viewer.addEventListener(Autodesk.Viewing.OBJECT_TREE_CREATED_EVENT, function () {
    listElements(function (listA, listB) {
      // make all elements as ghost
      viewer.isolate(-1);
      viewer.clearThemingColors(modelA);
      viewer.clearThemingColors(modelB);
      for (var extIdA in listA) {
        if (listB[extIdA] != null) continue;
        var dbIdA = listA[extIdA].dbId;
        removed[extIdA] = dbIdA;
        console.log("Removed dbId: " + dbIdA);
        viewer.impl.visibilityManager.show(dbIdA, modelA);
        viewer.setThemingColor(dbIdA, red, modelA);
      }
      for (var extIdB in listB) {
        if (listA[extIdB] != null) continue;
        var dbIdB = listB[extIdB].dbId
        added[extIdB] = dbIdB;
        console.log("Added dbId: " + dbIdB);
        viewer.impl.visibilityManager.show(dbIdB, modelB);
        viewer.setThemingColor(dbIdB, green, modelB);
      }
      for (var extId in listA) {
        if (typeof listB[extId] === "undefined") continue; // removed dbId
        var dbId = listA[extId].dbId; // should be the same as listB[extId]
        var propsA = listA[extId].properties;
        var propsB = listB[extId].properties;
        for (var i = 0; i < propsA.length; i++) {
          if (propsB[i] == null) continue;
          if (propsA[i].displayCategory.indexOf("__")==0) continue; // internal properties
          if (propsA[i].displayValue != propsB[i].displayValue) {
            console.log("Property " + dbId + ": " + propsA[i].displayName + " changed from "
              + propsA[i].displayValue + " to " + propsB[i].displayValue);
            modified[extId] = dbId;
          }
        }
        if (typeof modified[extId] != "undefined") {
          console.log("Modified dbId: " + dbId);
          // color on both models
          //viewer.impl.visibilityManager.show(dbId, modelA);
          //viewer.impl.visibilityManager.show(dbId, modelB);
          viewer.setThemingColor(dbId, orange, modelA);
          viewer.setThemingColor(dbId, orange, modelB);
        }
      }
    });
  });
  function listElements(callback) {
    getAllLeafComponents(modelA, function (modelAdbIds) {
      getAllLeafComponents(modelB, function (modelBdbIds) {
        // this count will help wait until getProperties end all callbacks
        var count = modelAdbIds.length + modelBdbIds.length;
        var modelAExtIds = {};
        modelAdbIds.forEach(function (modelAdbId) {
          modelA.getProperties(modelAdbId, function (modelAProperty) {
            modelAExtIds[modelAProperty.externalId] = {"dbId": modelAdbId, "properties": modelAProperty.properties};
            count--;
            if (count == 0) callback(modelAExtIds, modelBExtIds);
          });
        });
        var modelBExtIds = {};
        modelBdbIds.forEach(function (modelBdbId) {
          modelB.getProperties(modelBdbId, function (modelBProperty) {
            modelBExtIds[modelBProperty.externalId] = {"dbId": modelBdbId, "properties": modelBProperty.properties};
            count--;
            if (count == 0) callback(modelAExtIds, modelBExtIds);
          });
        });
      });
    });
  }
  function getAllLeafComponents(model, callback) {
    var components = [];
    function getLeafComponentsRec(tree, parentId) {
      if (tree.getChildCount(parentId) > 0) {
        tree.enumNodeChildren(parentId, function (childId) {
          getLeafComponentsRec(tree, childId);
        });
      }
      else
        components.push(parentId);
      return components;
    }
    var instanceTree = model.getInstanceTree();
    var allLeafComponents = getLeafComponentsRec(instanceTree, instanceTree.nodeAccess.rootId);
    callback(allLeafComponents);
  }
  return true;
};
VersionChanges.prototype.unload = function () {
  return true;
};
Autodesk.Viewing.theExtensionManager.registerExtension("Autodesk.Forge.Samples.VersionChanges", VersionChanges);

英文原文：https://forge.autodesk.com/bl...