LWO Loader incorrect placement of geometry and mesh when used with pivot point placement #26733
Comments
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I've been digging deeper... pivot: this.reader.getFloat32Array( 3 ), // Note: this seems to be superflous, as the geometry is translated when pivot is presentSo, I can see it actually records the pivot points. // TODO: z may need to be reversed to account for coordinate system change
geometry.translate( - layer.pivot[ 0 ], - layer.pivot[ 1 ], - layer.pivot[ 2 ] );So, now the mesh is in the incorrect place but the geometry has been shifted over to make it "look" like it's in the correct place. |
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Is that the best issue title you can come up with? 🤓 |
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I suspected I typed it in as a place holder so I could gather all the information and then make a better one.. |
WORMSS
changed the title
Correct. Pivot points like you know them from other engines/projects are not supported, see #15965. |
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As a workaround, instead of transforming the geometry couldn't you add a "dummy" instance of |
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Yeah, then we would just need to move the mesh so it's
This is getting it "roughly" into the correct position for rotation, but not quiet yet.. I will set up a proper test environment with some simple boxes in all the orientations so I can be sure it fixes all direction scenarios |
It's the loader that sets up the hierarchy structure during it's parsing phase..
BUT, I have just seen this on github... I don't remember coming across this when stepping through the code.. but maybe I was just tired..
I will try running this code 'raw' from github and see what happens when I do testing.. maybe it's already fixed but the CDN's don't have the fix... |
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Okay, just as another curiosity... Green Arrow = Where Z = 0 on the actual Model Red wireframe bar |
const boom_z = objects.boom.userData.pivot[2]; // 2 = z;;
objects.boom.geometry.translate(0, 0, boom_z * 2);
objects.boom.translateZ(-boom_z * 2);Finally got everything to align.. |
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Okay, this is how I eventually fixed the pivot points as things got more nested.. const { meshes } = await new LWOLoader().loadAsync(urlToLWOFile);
for ( const mesh of meshes ) {
fixPivots(mesh);
}
function fixPivots(mesh: THREE.Mesh) {
const [, , z] = mesh.userData.pivot;
const parentsZ = (mesh.parent?.userData.pivot[2] /* 2 = z */ ?? 0) * 2; // THIS was the killer blow..
mesh.geometry.translate(0, 0, z * 2);
mesh.translateZ(-z * 2 + parentsZ);
for (const child of mesh.children) {
fixPivots(child); // Fix Fix Fix ALL the way down.
}
} |
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I have fixed a similar issue in another loader by creating a custom 3D object class and implement pivot points there. In this way, you don't have to translate geometries but update the local/world matrices which is probably more what LWO expects. Maybe you can try to enhance class LWOMesh extends Mesh {
constructor() {
super();
this.pivot = new Vector3();
}
updateMatrix() {
this.matrix.compose( this.position, this.quaternion, this.scale );
const px = this.pivot.x;
const py = this.pivot.y;
const pz = this.pivot.z;
const te = this.matrix.elements;
te[ 12 ] += px - te[ 0 ] * px - te[ 4 ] * py - te[ 8 ] * pz;
te[ 13 ] += py - te[ 1 ] * px - te[ 5 ] * py - te[ 9 ] * pz;
te[ 14 ] += pz - te[ 2 ] * px - te[ 6 ] * py - te[ 10 ] * pz;
this.matrixWorldNeedsUpdate = true;
}
}Instead of creating instances of Would be great if you could give this a shot and report back how is it going. |
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Not gonna lie, I totally forgot about coming back here. I've been using my hack for so long.. I never got around to making a lwo object to test all this.. It was this and another problem I found with using the wrong property for colour with different paint types. |
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Without a test asset it's impossible to properly fix and test the issue. Closing for now. |
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@Mugen87 I DID IT.... And the fix "eventually" ended up being super simple... parsePoints(length: number) {
this.currentPoints = [];
for (var i = 0; i < length / 4; i += 3) {
- // z -> -z to match three.js right handed coords
+ // x -> -x to match three.js right handed coords
this.currentPoints.push(
- this.reader.getFloat32(),
+ -this.reader.getFloat32(),
this.reader.getFloat32(),
- -this.reader.getFloat32(),
+ this.reader.getFloat32(),
);
}
}also changed the pivot code. - var layer = {
- number: this.reader.getUint16(),
- flags: this.reader.getUint16(), // If the least significant bit of flags is set, the layer is hidden.
- pivot: this.reader.getFloat32Array( 3 ), // Note: this seems to be superflous, as the geometry is translated when pivot is present
- name: this.reader.getString(),
- };
+ const number = this.reader.getUint16();
+ const flags = this.reader.getUint16(); // If the least significant bit of flags is set, the layer is hidden.
+ const [x, y, z] = this.reader.getFloat32Array(3);
+ var layer = {
+ number,
+ flags, // If the least significant bit of flags is set, the layer is hidden.
+ pivot: [-x, y, z], // Note: this seems to be superflous, as the geometry is translated when pivot is present
+ name: this.reader.getString(),
+ };that fix was slightly less nice. But now, when I have a model that faces +z in Lightwave, it now correctly faces +z in three.js Also all the pivot points just "magically" work and has allowed me to get rid of nasty hack I had to run on every model load. function* flat<T>(meshes: T | T[]) {
if (Array.isArray(meshes)) {
yield* meshes;
} else {
yield meshes;
}
}
function* getObjects(meshes: THREE.Object3D | THREE.Object3D[]): Generator<THREE.Object3D> {
for (const mesh of flat(meshes)) {
yield mesh;
for (const m of mesh.children) {
yield* getObjects(m);
}
}
}
function fixPivots(meshes: THREE.Object3D[]) {
for (const mesh of getObjectsRecursive(meshes)) {
if (!(mesh instanceof THREE.Mesh) && !(mesh instanceof THREE.Points)) {
continue;
}
const [, , z] = mesh.userData?.pivot ?? [0, 0, 0]; // THIS IS
const parentsZ = (mesh.parent?.userData?.pivot?.[2] ?? 0) * 2; // COMPLETE AND
mesh.geometry.translate(0, 0, z * 2); // UTTER MADNESS
mesh.translateZ(-z * 2 + parentsZ); // I HATE IT
}
}and my other really bizarre stuff I had to do is also much MUCH simplified export function resetMatrix(matrix: THREE.Matrix3) {
return matrix.set(1, 0, 0, 0, 1, 0, 0, 0, 1);
}
export function resetVectorApplyMatrix(vector: THREE.Vector2, matrix: THREE.Matrix3) {
return vector.set(0, 0).applyMatrix3(matrix);
}
export function linkPiston(cylinder: THREE.Object3D, ram: THREE.Object3D) {
const arm = ram.parent;
if (!arm) {
throw new Error('Ram Parent is null');
}
// NEED A VERY SPECIFIC PARENT STRUCTURE TO MAKE THIS WORK
if (!cylinder.parent?.children.includes(arm)) {
throw new Error('Cylinder and Ram-Parent not siblings, you will need custom logic');
}
const siblingOffset = new THREE.Vector2(
arm.position.z - cylinder.position.z,
arm.position.y - cylinder.position.y,
);
const vector = new THREE.Vector2();
const matrix = new THREE.Matrix3();
let lastRotation: number | null;
return {
update() {
resetMatrix(matrix);
matrix.translate(ram.position.z, ram.position.y); // APPLY THE
matrix.rotate(arm.rotation.x); // MATRIX IN
matrix.translate(siblingOffset.x, siblingOffset.y); // REVERSE ORDER
resetVectorApplyMatrix(vector, matrix);
const cylinderRot = -vector.angle() + T(0.5);
cylinder.rotation.x = cylinderRot;
ram.rotation.x = cylinderRot - T(0.5) - currentRotation;
},
};
}TO THIS export function linkPiston(cylinder: THREE.Object3D, ram: THREE.Object3D) {
const tmp = new THREE.Vector3(0, 0, 0);
return {
update() {
ram.lookAt(cylinder.getWorldPosition(tmp));
cylinder.lookAt(ram.getWorldPosition(tmp));
},
};
}As you can imagine, I am very much happier to get rid of this hacky code once I realised what the problem was |
fix: IFFParser.js now reads x as -x instead of z to -z. This now sets the geometry and pivot points in the correct location. This fixes mrdoob#26733
fix: IFFParser.js now reads x as -x instead of z to -z. This now sets the geometry and pivot points in the correct location. This fixes mrdoob#26733
* [Loader] Fix for LWOLoader geometry correction fix: IFFParser.js now reads x as -x instead of z to -z. This now sets the geometry and pivot points in the correct location. This fixes #26733 * fix: webgl_loader_lwo updated with corrected coordinates for meshes and lights and cameras
Description
Hello, I've made a few objects in Lightwave and I use the LWOLoader to load them.
Layer 1, I modeled an object around
0,0,0and I apply rotation on that mesh, and everything works as expected.On Layer 2, I modeled another object but I positioned it where it should be relative to Layer 1. But, being a little clever boy, I set the pivot point (Lets just say
2,1,0). In Lightwave when I tell to rotate from the pivot point, it moves as expected.But when I use THREE to rotate the mesh, it rotates from
0,0,0and not2,1,0.Anyone know how to make LWO respect the layer's Pivot Point?
Reproduction steps
Code
// code goes hereLive example
Screenshots
No response
Version
r156
Device
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Browser
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OS
No response
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