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three.jsautodesk-forgeautodesk-viewer

THREE.js raycaster intersectObject method returns no intersection when checking if point is inside mesh

I want to check whether a point is inside a mesh or not. To do so, I use a raycaster, set it to the point's origin and if the ray intersects the mesh only once, it must be inside. Unfortunately, the intersectObject always returns no intersection, even in cases I know that the point is located inside the mesh. The point's origin is given in world coordinates and the mesh's matrixWorld is up to date too. Also, I set the mesh.material.side to THREE.DoubleSide, so that the intersection from inside should be detected. I tried setting the recursive attribute to true as well, but as expected, this didn't have any effect (since the mesh is a box geometry). The mesh is coming from the Autodesk Forge viewer interface. Here is my code:

mesh.material.side = THREE.DoubleSide;
const raycaster = new THREE.Raycaster();
let vertex = new THREE.Vector3();
vertex.fromArray(positions, positionIndex);
vertex.applyMatrix4(matrixWorld);
const rayDirection = new THREE.Vector3(1, 1, 1).normalize();
raycaster.set(vertex, rayDirection);
const intersects = raycaster.intersectObject(mesh);
if (intersects.length % 2 === 1) {
   isPointInside = true;
}

The vertex looks like this (and it obviosly lies inside of the bounding box):

vertex world coordinates

The mesh is a box shaped room with the following bounding box:

room bounding box

The mesh looks like this:

mesh

The geometry of the mesh holds the vertices in the vb. After applying the world matrix, the mesh vertices are correct in world space. Here is a part of the vb list:

enter image description here

Why does the raycaster not return any intersection? Is the matrixWorld of the mesh taken into account when computing the intersections?

Thanks for any kind of help!

Solution

  • Note that Forge Viewer is based on three.js version R71, and it had to modify/reimplement some parts of the library to handle large and complex models (especially architecture and infrastructure designs), so THREE.Mesh objects might have a slightly different structure. In that case I'd suggest to raycast using Forge Viewer's own mechanisms, e.g., using viewer.impl.rayIntersect(ray, ignoreTransparent, dbIds, modelIds, intersections);.