无法在场景中为OBJMTLLoader对象设置本地原点

Question

I am creating a scene using Three.js where I can move objects around. I used the OBJMTLLoader to load in the objects. However, these objects don't have a local origin, they still store their original origins. When I go to move an object, the object first moves back to its original origin, and then you can move the object from there. I have found lots of examples of using centroids and bounding boxes, but I always get that something is undefined. Any help would be greatly appreciated!!

loader.load('example.obj', 'example.mtl', function (object) {
            object.position.y = -50; // I want this to be the new origin of the object
            object.scale.set(scale, scale, scale);
        });

And then my code to move the object:

function onDocumentMouseMove(event) {
    event.preventDefault();
    mouse.x = ( (event.clientX - container.offsetLeft) / container.clientWidth ) * 2 - 1;
    mouse.y = -( (event.clientY - container.offsetTop ) / container.clientHeight) * 2 + 1;

    raycaster.setFromCamera(mouse, camera);

    if (SELECTED) {
        var intersects = raycaster.intersectObject(plane);
        SELECTED.position.copy(intersects[0].point.sub(offset));
        return;
    }

    var intersects = raycaster.intersectObjects(objects);
    if (intersects.length > 0) {
        if (INTERSECTED != intersects[0].object) {
            INTERSECTED = intersects[0].object;
            plane.position.copy(INTERSECTED.position);
            plane.lookAt(camera.position);
            updateLightPosition();
        }
        container.style.cursor = 'pointer';
    } else {
        INTERSECTED = null;
        container.style.cursor = 'auto';
    }
}

function onDocumentMouseDown(event) {
    event.preventDefault();
    var vector = new THREE.Vector3(mouse.x, mouse.y, 1).unproject(camera);
    raycaster.set(camera.position, vector.sub(camera.position).normalize());
    if (selectingTargetPos) {
        var intersects = raycaster.intersectObjects(background);
        if (intersects.length > 0) {
            selectedObject.light.target = new THREE.Object3D();
            selectedObject.light.target.position.copy(intersects[0].point);
            selectedObject.light.target.updateMatrixWorld();
            selectingTargetPos = false;
            container.style.cursor = 'auto';
        }
    } else if (selectingTargetObj) {
        var intersects = raycaster.intersectObjects(objects);
        if (intersects.length > 0) {
            selectedObject.light.target = intersects[0].object;
            selectedObject.light.target.updateMatrixWorld();
            selectingTargetObj = false;
            container.style.cursor = 'auto';
        }
    } else {
        var intersects = raycaster.intersectObjects(objects, true);
        if (intersects.length > 0) {
            SELECTED = intersects[0].object.userData.rootObject;
            selectedObject = SELECTED;
            var intersects = raycaster.intersectObject(plane);
            offset.copy(intersects[0].point).sub(plane.position);
            container.style.cursor = 'move';
        }
    }
}

function onDocumentMouseUp(event) {
    event.preventDefault();
    SELECTED = null;
    container.style.cursor = 'auto';
}

Answer 1

Because the object position is based off of the plane and the objects are grouped, the problem lies in the INTERSECTED block of the onDocumentMouseMove() event.

This does not get triggered because the raycaster is not recursively checking the objects array. By changing the intersectObjects() function to have a second parameter of true, the problem will be solved.

var intersects = raycaster.intersectObjects(objects, true);
if (intersects.length > 0) {
    if (INTERSECTED != intersects[0].object) {
        INTERSECTED = intersects[0].object;
        plane.position.copy(INTERSECTED.position);
        plane.lookAt(camera.position);
        updateLightPosition();
    }
    container.style.cursor = 'pointer';
} else {
    INTERSECTED = null;
    container.style.cursor = 'auto';
}