How to calculate transformed skin vertices? - three.js

The code I tried:
var transformedSkinVertex = function (skin, index) {
var skinIndices = (new THREE.Vector4 ()).fromAttribute (skin.geometry.getAttribute ('skinIndex'), index);
var skinWeights = (new THREE.Vector4 ()).fromAttribute (skin.geometry.getAttribute ('skinWeight'), index);
var skinVertex = (new THREE.Vector3 ()).fromAttribute (skin.geometry.getAttribute ('position'), index).applyMatrix4 (skin.bindMatrix);
var result = new THREE.Vector3 (), temp = new THREE.Vector3 (), tempMatrix = new THREE.Matrix4 (); properties = ['x', 'y', 'z', 'w'];
for (var i = 0; i < 4; i++) {
var boneIndex = skinIndices[properties[i]];
tempMatrix.multiplyMatrices (skin.skeleton.bones[boneIndex].matrixWorld, skin.skeleton.boneInverses[boneIndex]);
result.add (temp.copy (skinVertex).multiplyScalar (skinWeights[properties[i]]).applyMatrix4 (tempMatrix));
}
return result.applyMatrix4 (skin.bindMatrixInverse);
};
This works for T pose:
But with arms lowered some parts explode into angel-like shape:
Here is arms placed slightly differently:
My current theory is that this happens when there are > 2 bones. But... why?
All weights correctly add up to 1, as you can see above three.js renders the skin correcty.

Resolved.
Correct line is
result.add (temp.copy (skinVertex).applyMatrix4 (tempMatrix).multiplyScalar (skinWeights[properties[i]]));
I did not think the order of multiplication by scalar would matter.

Related

Points Intersection of BufferGeometry

I'm trying to adapt this example or this discussion, but when I use new library, there is no more face and vertices in geometry properties.
The structures is differenet, so I confuse to use the Index->array and Attrirube->Position to change this code:
`
obj.geometry.faces.forEach(function(face, idx) {
obj.localToWorld(a.copy(obj.geometry.vertices[face.a]));
obj.localToWorld(b.copy(obj.geometry.vertices[face.b]));
obj.localToWorld(c.copy(obj.geometry.vertices[face.c]));
lineAB = new THREE.Line3(a, b);
lineBC = new THREE.Line3(b, c);
lineCA = new THREE.Line3(c, a);
console.log("lineAB", lineAB);
console.log("lineBC", lineBC);
console.log("lineCA", lineCA);
setPointOfIntersection(lineAB, mathPlane, idx);
setPointOfIntersection(lineBC, mathPlane, idx);
setPointOfIntersection(lineCA, mathPlane, idx);
});
`
Any idea how to do it? Please help.. Thanks in advance~
Since r125, there is no Geometry class anymore. All geometries are BufferGeometry now. Thus, vertices are stored in geometry.attributes.position.
BufferGeometry can be indexed or non-indexed:
Indexed means that faces defined with triplets of incides of
vertices.
Non-indexed means that faces defined with triplets of
vertices.
So, this part of code:
var a = new THREE.Vector3(),
b = new THREE.Vector3(),
c = new THREE.Vector3();
obj.geometry.faces.forEach(function(face) {
obj.localToWorld(a.copy(obj.geometry.vertices[face.a]));
obj.localToWorld(b.copy(obj.geometry.vertices[face.b]));
obj.localToWorld(c.copy(obj.geometry.vertices[face.c]));
lineAB = new THREE.Line3(a, b);
lineBC = new THREE.Line3(b, c);
lineCA = new THREE.Line3(c, a);
setPointOfIntersection(lineAB, mathPlane);
setPointOfIntersection(lineBC, mathPlane);
setPointOfIntersection(lineCA, mathPlane);
});
needs some changes.
var a = new THREE.Vector3(),
b = new THREE.Vector3(),
c = new THREE.Vector3();
var isIndexed = obj.geometry.index != null; // if geometry is indexed or non-indexed
var pos = obj.geometry.attributes.position; // attribute with positions
var idx = obj.geometry.index; // index
var faceCount = (isIndexed ? idx.count : pos.count) / 3; // amount of faces
for(let i = 0; i < faceCount; i++) {
let baseIdx = i * 3;
let idxA = baseIdx + 0;
a.fromBufferAttribute(pos, isIndexed ? idx.getX(idxA) : idxA);
// .fromBufferAttribute is a method of Vector3
// .getX is a method of BufferAttribute
let idxB = baseIdx + 1;
b.fromBufferAttribute(pos, isIndexed ? idx.getX(idxB) : idxB);
let idxC = baseIdx + 2;
c.fromBufferAttribute(pos, isIndexed ? idx.getX(idxC) : idxC);
obj.localToWorld(a);
obj.localToWorld(b);
obj.localToWorld(c);
lineAB = new THREE.Line3(a, b);
lineBC = new THREE.Line3(b, c);
lineCA = new THREE.Line3(c, a);
setPointOfIntersection(lineAB, mathPlane);
setPointOfIntersection(lineBC, mathPlane);
setPointOfIntersection(lineCA, mathPlane);
});
PS Haven't tested this snippet, changes from scratch. Possible typos.

How to access the BufferGeometry of IFC items in web-ifc-three

I'm trying to get the geometry of an element
i.e. a BufferGeometry object corresponding to an expressId I have (not through picking).
Basically I'm asking how to traverse the IFC model and export each object as a separate OBJ.
I'll note I have reverse engineered code to achieve that for some version of the package, but it uses undocumented functionality, so naturally it broke in later versions (the code also colors the geometry according to the material's color so I don't need an mtl):
Don't copy this code it won't work
Object.values(bimModel.ifcManager.state.models[bimModel.modelID].items).forEach(type => {
Object.entries(type.geometries).forEach(([id, geometry]) => {
const properties = bimModel.getItemProperties(Number(id))
const numVertices = geometry.getAttribute('position').count
const color = type.material.color.toArray().map(x => x * 255)
const vertexColors = new Uint8Array(Array.from({ length: numVertices }, () => color).flat())
geometry.setAttribute('color', new BufferAttribute(vertexColors, 3, true))
})
})
This is exactly what we do to export models to glTF. The basic workflow is:
Decide what IFC categories you would like to export.
Get all the items of each category.
Reconstruct the mesh for each item.
Export the mesh using the Three.js exporter of your choice.
Let's see a basic example to get all the meshes from the walls. The process is not as straightforward as having each IFC item as a separate mesh, but that's the price for having the draw calls at minimum (otherwise, a browser wouldn't stand even medium-sized IFC files):
import { IFCWALLSTANDARDCASE } from 'web-ifc';
async function getAllWallMeshes() {
// Get all the IDs of the walls
const wallsIDs = manager.getAllItemsOfType(0, IFCWALL, false);
const meshes = [];
const customID = 'temp-gltf-subset';
for (const wallID of wallsIDs) {
const coordinates = [];
const expressIDs = [];
const newIndices = [];
const alreadySaved = new Map();
// Get the subset for the wall
const subset = viewer.IFC.loader.ifcManager.createSubset({
ids: [wallID],
modelID,
removePrevious: true,
customID
});
// Subsets have their own index, but share the BufferAttributes
// with the original geometry, so we need to rebuild a new
// geometry with this index
const positionAttr = subset.geometry.attributes.position;
const expressIDAttr = subset.geometry.attributes.expressID;
const newGroups = subset.geometry.groups
.filter((group) => group.count !== 0);
const newMaterials = [];
const prevMaterials = subset.material;
let newMaterialIndex = 0;
newGroups.forEach((group) => {
newMaterials.push(prevMaterials[group.materialIndex]);
group.materialIndex = newMaterialIndex++;
});
let newIndex = 0;
for (let i = 0; i < subset.geometry.index.count; i++) {
const index = subset.geometry.index.array[i];
if (!alreadySaved.has(index)) {
coordinates.push(positionAttr.array[3 * index]);
coordinates.push(positionAttr.array[3 * index + 1]);
coordinates.push(positionAttr.array[3 * index + 2]);
expressIDs.push(expressIDAttr.getX(index));
alreadySaved.set(index, newIndex++);
}
const saved = alreadySaved.get(index);
newIndices.push(saved);
}
const geometryToExport = new BufferGeometry();
const newVerticesAttr = new BufferAttribute(Float32Array.from(coordinates), 3);
const newExpressIDAttr = new BufferAttribute(Uint32Array.from(expressIDs), 1);
geometryToExport.setAttribute('position', newVerticesAttr);
geometryToExport.setAttribute('expressID', newExpressIDAttr);
geometryToExport.setIndex(newIndices);
geometryToExport.groups = newGroups;
geometryToExport.computeVertexNormals();
const mesh = new Mesh(geometryToExport, newMaterials);
meshes.push(mesh);
}
viewer.IFC.loader.ifcManager.removeSubset(modelID, undefined, customID);
return meshes;
}

ThreeJS: Is there any possible way to reduce the amount of triangles count

Hi I have some very complex models to display which comes from Revit files that my customer provides.
But sometimes the amount of details in the model is just way too much for the purpose of the website.
I would like to reduce the amount of vertexes/triangles in the model to simplify the display and enhance performance.
I have used simply modifiers where I cant able to view the model itself.
Is this possible from within ThreeJS? Or is there maybe an other solution for this?
const renderMeshFunction = async (material: any, geometry: any, id: any) => {
let count = 0;
const emptyFunction = () => { };
const onBR = () => {
const _count = (count < 3 ? count : Math.floor(Math.random() * count) + 1);
return ((renderer: WebGLRenderer, scene: Scene,
camera: Camera, geometry: Geometry | BufferGeometry,
_material: Material, group: Group) => {
_material.clippingPlanes = checkIsClipping();
});
};
count = geometry.maxInstancedCount;
const mesh = new Mesh(geometry, material);
let modifier = new SimplifyModifier();
let simplified = mesh.clone();
simplified.material = simplified.material.clone();
let countSimple = Math.floor((simplified.geometry as any).attributes.position.count * 1); // number of vertices to remove
simplified.geometry = modifier.modify(simplified.geometry, countSimple);
that.scene.add(simplified);
mesh.name = id || Date.now().toString();
mesh.matrixAutoUpdate = false;
mesh.drawMode = 0;
mesh.onBeforeRender = onBR.apply(that);
mesh.onAfterRender = emptyFn;
mesh.geometry.dispose();
mesh.material.dispose();
geometry.dispose();
material.dispose();
material = undefined;
return mesh;
};

Cocos Creator js animate sprite

I have animated a sprite using a sprite sheet and the update function,
like so:
Note: I have dragged the plist into the atlas field of the sprite node (the same node the monster.js script is attached to) in the Ccos Creator UI.
//monster.js
onLoad: function(){
// change monsters face
this.faces['1'] = 'monster1';
this.faces['2'] = 'monster2';
this.faces['3'] = 'Rmonster1';
this.faces['4'] = 'Rmonster2';
}
update: function (dt) {
this.timekeep += dt;
if(this.timekeep > 0.1){
var self = this;
cc.loader.loadRes('monsters', cc.SpriteAtlas, function (err, atlas) {
self.getComponent(cc.Sprite).spriteFrame = atlas.getSpriteFrame(self.faces[self.monstersN]);
});
this.timekeep = 0;
this.monstersN++;
if(this.monstersN > 4){
this.monstersN = 1;
}
}
It actually works fine. I have already thought I should export the cc.loader.loaderRes into the onLoad function and save the atlas as a global var instead of loading every time the update is called.
However…seeing that there are built in animation functions, this can’t be the correct solution. So I tried this:
onLoad: function () {
// change monster face
this.faces['1'] = 'monster1';
this.faces['2'] = 'monster2';
this.faces['3'] = 'Rmonster1';
this.faces['4'] = 'Rmonster2';
var self = this;
cc.loader.loadRes('monsters', cc.SpriteAtlas, function (err, atlas) {
var sprite = self.getComponent(cc.Sprite);
var animFrames = [];
for (var i = 1; i < 4; i++) {
var spriteFrame = atlas.getSpriteFrame(self.faces[i]);
var animFrame = new cc.AnimationFrame();
animFrame.initWithSpriteFrame(spriteFrame, 1, null);
animFrames.push(animFrame);
}
var animation = sprite.Animation.create(animFrames, 0.2, 100);
var animate = sprite.Animate.create(animation);
sprite.runAction(animate);
});
},
I get this error:
cc.AnimationFrame is not a constructor
So then I tried this:
onLoad: function () {
// change monster face
this.faces['1'] = 'monster1';
this.faces['2'] = 'monster2';
this.faces['3'] = 'Rmonster1';
this.faces['4'] = 'Rmonster2';
var self = this;
cc.loader.loadRes('monsters', cc.SpriteAtlas, function (err, atlas) {
self.atlasA = atlas;
});
var sprite = this.getComponent(cc.Sprite);
var animFrames = [];
for (var i = 1; i < 4; i++) {
var spriteFrame = this.atlasA.getSpriteFrame(this.faces[i]);
var animFrame = new cc.AnimationFrame();
animFrame.initWithSpriteFrame(spriteFrame, 1, null);
animFrames.push(animFrame);
}
var animation = sprite.Animation.create(animFrames, 0.2, 100);
var animate = sprite.Animate.create(animation);
sprite.runAction(animate);
},
I get this error:
Cannot read property ‘getSpriteFrame’ of undefined
How can I use cc.animate to change the sprite using the spritesheet I have. All I want to achieve is to move through the plist in the order the images are in the plist, repeated until the monster is put back into the pool it came from.
Here is the solution for anyone who may still be looking.....
cc.AnimationClip.createWithSpriteFrames([sf1, sf2, ...], fps)

Actionscript - randomly drop from moving plane MC

I wasn't quite sure how to describe my problem in the subject. I have a plane MC and a crate MC. The plane only flies along the y axis from the bottom of the screen to top. Along the way I want it to randomly drop the crate MC. My code is below. The problem is that the crates spontaneously keep spawning and not near the plane.
function movePlane():void
{
var tempY:Number;
var tempX:Number;
var tempCrate:MovieClip;
var tempPlane:MovieClip;
for (var j:int =planes.length-1; j>=0; j--)
{
tempPlane = planes[j];
tempPlane.y += tempPlane.planeSpeed;
tempCrate = new Crate();
tempY = Math.floor(Math.random() * tempPlane.y);
tempX = Math.floor(Math.random() * tempPlane.x);
}
tempCrate.y = tempY;
tempCrate.x = tempX;
addChild(tempCrate);
}
Edited answer:
To make a crate drop on each plane once you can create this behavior by creating a timer on each plane with a random time value. Like this:
function addRandomCreation():void{
var animationTime:Number = 5000; //The time the planes will be animating in ms
for(var i:int = 0; i < planes.length; i++){
var planeTimer:Timer = new Timer(Math.round(animationTime * Math.random()));
planeTimer.addEventListener(TimerEvent.TIMER, timerComplete(i));
planeTimer.start();
}
}
function timerComplete(planeID:int):function{
return function(event:TimerEvent):void{
event.target.stop();
event.target.removeEventListener(event.type, arguments.callee);
var tempCrate:MovieClip = new Crate();
tempY = Math.round(Math.random() * planes[planeID].y);
tempCrate.y = tempY;
tempCrate.x = planes[planeID].x;
addChild(tempCrate);
}
}
Edited answer:
This will create a crate on the same x axis as the plane it's being created by.
function movePlane():void
{
var tempY:Number;
var tempX:Number;
var tempCrate:MovieClip;
var tempPlane:MovieClip;
for (var j:int =planes.length-1; j>=0; j--)
{
tempPlane = planes[j];
tempPlane.y += tempPlane.planeSpeed;
tempCrate = new Crate();
tempY = Math.floor(Math.random() * tempPlane.y);
tempCrate.y = tempY;
tempCrate.x = tempPlane.x;
addChild(tempCrate);
}
}
You have have to use addChild each time you create a new Crate otherwise it will just create a lot of crates which only the last one will be added to the stage. To do this you have to move the addChild into the loop.
function movePlane():void
{
var tempY:Number;
var tempX:Number;
var tempCrate:MovieClip;
var tempPlane:MovieClip;
for (var j:int =planes.length-1; j>=0; j--)
{
tempPlane = planes[j];
tempPlane.y += tempPlane.planeSpeed;
tempCrate = new Crate();
tempY = Math.floor(Math.random() * tempPlane.y);
tempX = Math.floor(Math.random() * tempPlane.x);
tempCrate.y = tempY;
tempCrate.x = tempX;
addChild(tempCrate);
}
}

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