無法在場景中為OBJMTLLoader對象設置本地原點

Question

我正在使用Three.js創建一個場景，可以在其中移動對象。 我使用OBJMTLLoader加載對象。 但是，這些對象沒有本地原點，它們仍存儲其原始原點。 當我去移動一個對象時，該對象首先移回其原始位置，然后可以從那里移動該對象。 我發現了很多使用質心和邊界框的示例，但是我總是得到一些未定義的信息。 任何幫助將不勝感激！！

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);
        });

然后我的代碼移動對象：

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

因為對象位置基於平面，並且對象已分組，所以問題出在onDocumentMouseMove()事件的INTERSECTED塊中。

這不會被觸發，因為光線投射器沒有遞歸檢查對象數組。 通過將intersectObjects()函數更改為第二個參數true，可以解決該問題。

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';
}