如何在 2D 视图中使用 dbid 获取位置

Question

有一个类似的问题： How to get location with dbid in 2D

但尚未得到答复。

所以我有同样的问题，有没有办法在 2D 视图中使用 dbid 获取对象位置信息？

我们的产品要求标记某些对象并将 dbids 保存在外部数据库中，下次打开模型时，我们需要使用这些 ids 并找到位置，然后绘制一些自定义形状来突出显示这些对象。

我尝试使用viewer.impl.highlightObjectNode，但它只能显示被选中的对象，它对自定义虚拟化非常有限。

Answer 1

这里有一些代码sn-ps来访问Forge碎片的网格信息，它可以帮助你找到某个Forge查看器dbId的位置。更多信息可以参考这个extension：https://github.com/Autodesk-Forge/library-javascript-viewer-extensions/blob/master/src/Autodesk.ADN.Viewing.Extension.MeshData/Autodesk.ADN.Viewing.Extension.MeshData.js

此外，viewer.impl.highlightObjectNode 仅用于突出显示元素，根据我的经验，它不能用于其他用途。

  function getLeafFragIds( model, leafId ) {
    const instanceTree = model.getData().instanceTree;
    const fragIds = [];

    instanceTree.enumNodeFragments( leafId, function( fragId ) {
      fragIds.push( fragId );
    });

    return fragIds;
  }

  function getComponentGeometry( viewer, dbId ) {

    const fragIds = getLeafFragIds( viewer.model, dbId );

    let matrixWorld = null;

    const meshes = fragIds.map( function( fragId ) {

      const renderProxy = viewer.impl.getRenderProxy( viewer.model, fragId );

      const geometry = renderProxy.geometry;
      const attributes = geometry.attributes;
      const positions = geometry.vb ? geometry.vb : attributes.position.array;

      const indices = attributes.index.array || geometry.ib;
      const stride = geometry.vb ? geometry.vbstride : 3;
      const offsets = geometry.offsets;

      matrixWorld = matrixWorld || renderProxy.matrixWorld.elements;

      return {
        positions,
        indices,
        offsets,
        stride
      };
    });

    return {
      matrixWorld,
      meshes
    };
  }

  var meshInfo = getComponentGeometry( viewer, 1234 );

Answer 2

你也可以在viewer3D.js中勾选“viewer.impl.fitToView”，这个函数计算选定的对象联合边界框并使其适合查看，所以我从这个函数中提取代码来获取对象边界框中心坐标及其dbid

function getObjectBound2D(viewer, objectId) {
    var model = viewer.model;
    // This doesn't guarantee that an object tree will be created but it will be pretty likely
    var bounds, bc, i;
    if (model.is2d()) {
        bounds = new THREE.Box3();
        // move this next one up into the calling method
        bc = new avp.BoundsCallback(bounds);

        var dbId2fragId = model.getData().fragments.dbId2fragId;

        var fragIds = dbId2fragId[objectId];
        // fragId is either a single vertex buffer or an array of vertex buffers
        if (Array.isArray(fragIds)) {
            for (var j = 0; j < fragIds.length; j++) {
                // go through each vertex buffer, looking for the object id
                find2DBounds(model, fragIds[j], objectId, bc);
            }
        } else if (typeof fragIds === 'number') {
            // go through the specific vertex buffer, looking for the object id
            find2DBounds(model, fragIds, objectId, bc);
        }

        // should have some real box at this point; check
        if (!bounds.empty()) {
            return bounds;
        }
    }

    function find2DBounds(model, fragId, dbId, bc) {
        var mesh = model.getFragmentList().getVizmesh(fragId);
        var vbr = new avp.VertexBufferReader(mesh.geometry);
        vbr.enumGeomsForObject(dbId, bc);
    }

    function find2DLayerBounds(model, fragId, bc) {
        var mesh = model.getFragmentList().getVizmesh(fragId);
        var vbr = new avp.VertexBufferReader(mesh.geometry);
        var visibleLayerIds = that.getVisibleLayerIds();
        vbr.enumGeomsForVisibleLayer(visibleLayerIds, bc);
    }
};

var objBoundingbox = getObjectBound2D(viewer,dbid);

var objCenterCoordinates = objBoundingbox.center();