问题
I used STLLoader to load an stl onto a threeJS scene returning a BufferGeometry.
I then used
myMesh.position.set( x,y,z )
myMesh.rotation.setFromQuaternion ( quaternion , 'XYZ');
to translate the geometry. This effectively changes the
myMesh.position
myMesh.quaternion
Translation is happening in the scene and all works well. I expected that the
myMesh.geometry.attributes.position.array
would be different before and after the translation - but it remained identical. I want to extract the new veritces from the buffergeometry after translation. I tried to call
myMesh.geometry.dynamic = true;
myMesh.geometry.attributes.position.needsUpdate = true;
in the render loop but no luck as I haven't updated the vertices explicity.
回答1:
You want to get the world position of a mesh's geometry, taking into consideration the mesh's transform matrix, mesh.matrix
. Also, your mesh geometry is THREE.BufferGeometry
.
Here is the pattern to follow:
mesh = new THREE.Mesh( geometry, material );
mesh.position.set( 10, 10, 10 );
mesh.rotation.set( - Math.PI / 2, 0, 0 );
mesh.scale.set( 1, 1, 1 );
scene.add( mesh );
mesh.updateMatrix(); // make sure the mesh's matrix is updated
var vec = new THREE.Vector3();
var attribute = mesh.geometry.attributes.position; // we want the position data
var index = 1; // index is zero-based, so this the the 2nd vertex
vec.fromAttribute( attribute, index ); // extract the x,y,z coordinates
vec.applyMatrix4( mesh.matrix ); // apply the mesh's matrix transform
three.js r.71
来源:https://stackoverflow.com/questions/32430260/threejs-buffergeometry-position-attribute-not-updating-when-translation-applied