How to get coordinates i.e vertices from an object - autodesk-forge

Question

I am trying to get geometry data one element at a time such as vertices.
What I tried so far:
fragproxy = viewer.gui.impl.getFragmentProxy(model,fragid) gives me some kind of geometry, but not any vertices, which I can access by dbId
frags = viewer.gui.model.getFragmentList() gives me a fragId to dbId map but no no connection from dbId to geometry
Does anyone know a method to get the geometry with the vertices ?

Answer 1

The positions value of the following code snippets is the vertices what you want.
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 );
Since this information of the Forge fragment is stored in a flatten storage, please check the demo extension Autodesk.ADN.Viewing.Extension.MeshData.js if you want to rebuild the meshing relationship.
Hope it helps!