I want to create a grid of, let's say 500x500, and I want it to be able to be curved in certain places (think of it as space-time plane that's curved due to gravity). I'm stuck at the start.
This is what I found on the documentation:
// Create a sine-like wave
const curve = new THREE.SplineCurve( [
new THREE.Vector2( -10, 0 ),
new THREE.Vector2( -5, 5 ),
new THREE.Vector2( 0, 0 ),
new THREE.Vector2( 5, -5 ),
new THREE.Vector2( 10, 0 )
] );
const points = curve.getPoints( 50 );
const geometry = new THREE.BufferGeometry().setFromPoints( points );
const material = new THREE.LineBasicMaterial( { color : 0xff0000 } );
// Create the final object to add to the scene
const splineObject = new THREE.Line( geometry, material );
I think this should be working but it doesn't. I don't know how to create a multiple lines from here. I tried to handle some array but I didn't know where or how. I have done my research but I can't make any headway.
I have another question: Is that this is a Vector2 I need to make it 3d for that work? There a lot of other classes like CatmullRomCurve3, CubicBezierCurve3, etc, but the problem still is that i need to make an array to create all the vectors and lines.
--
EDIT i created a code for the grid lines but the curve probleme still the same
let size = 12, step = 1;
const geometry = new THREE.BufferGeometry();
// create a simple square shape. We duplicate the top left and bottom right
// vertices because each vertex needs to appear once per triangle.
const vertices = [];
for(var i = - size; i <= size; i += step) {
vertices.push( - size, - 0.4, i);
vertices.push( size, - 0.4, i);
vertices.push( i, - 0.4, - size);
vertices.push( i, - 0.4, size);
}
let positionAttribute = new THREE.Float32BufferAttribute(vertices, 3);
geometry.setAttribute("position", positionAttribute);
let lines = new THREE.LineSegments(geometry, new THREE.LineBasicMaterial());
I am trying to draw a curved road in three.js from some beziers I get with previous calculations, the problem is that I can't find the way to convert the sequence of curved lines (one starting at the end of the previous one) to a curved plane.
I have a 3D scene where there are some cars, a road created with a plane and the path of the coming road is painted. I use that Bezier curves I said to represent the path as a Line with
function createAdasisBezier(initx, inity, cp1x, cp1y, cp2x, cp2y, finalx, finaly) {
bezier = new THREE.CubicBezierCurve3(
new THREE.Vector3(initx, inity, 0),
new THREE.Vector3(cp1x, cp1y, 0),
new THREE.Vector3( cp2x, cp2y, 0),
new THREE.Vector3(finalx, finaly, 0)
);
curvePath = new THREE.CurvePath();
curvePath.add(bezier);
var geoPath = curvePath.createPointsGeometry( 5 );
var lineMat = new THREE.LineBasicMaterial({color: 0xff0000});
curveLine = new THREE.Line(geoPath, lineMat);
curveLine.rotation.set(-Math.PI/2,0,0);
curveLine.position.y = 0.1;
scene.add(curveLine);
}
First, I tried extruding the line, but then I realized that it might not be the solution because I wanted to do a road, and although I could move top vertices on X and Y to place them near the bezier in order to be the external part of the curve, the result was not only unfavourable, it also made impossible to preserve a relation between a left and a right curve.
To move vertices (once identified) I did a loop and move them manually:
for (var i = 0; i < geoPath.vertices.length; ++i) {
geoPath.vertices[i].y += 10;
}
Bevel is not enabled in the extude.
Then I tried to draw a plane over each bezier (as a child of them) and rotate it to face the path, but the result was not as I expected, and it if it were, it would spoil the arcs of the curves.
To do it, I created a copy of every bezier, and place it aside the original ones, then I created the plane.
var plane = new THREE.PlaneBufferGeometry(10,25,1,1);
var planemesh = new THREE.Mesh(plane, material);
planemesh.position.set(copy.geometry.vertices[0].x, copy.geometry.vertices[0].y, 0);
Last thing I was trying to do is creating a clone of the line, separate it some meters and "connect" the first vertex from one, to the first of the other, so I get a closed geometry, and I can create a Face, but I don't find how to "connect" vertices from 2 different geometries. I tried adding the vertex from one to the other, but it did not work.
Does anybody have an idea how could I convert the line into a curved road? Thanks in adcance.
You should try looking at the Geometry > Extrude > Shapes example. As you can see, all extruded shapes maintain their width and direction, despite turning left/right or looping completely.
Instead of using bezier curves, they're using a CatmullRomCurve3 to define the extrusion. If you look at the source code, the essential code to make the red extruded shape begins in line 69:
// Define the curve
var closedSpline = new THREE.CatmullRomCurve3( [
new THREE.Vector3( -60, -100, 60 ),
new THREE.Vector3( -60, 20, 60 ),
new THREE.Vector3( -60, 120, 60 ),
new THREE.Vector3( 60, 20, -60 ),
new THREE.Vector3( 60, -100, -60 )
] );
closedSpline.type = 'catmullrom';
closedSpline.closed = true;
// Set up settings for later extrusion
var extrudeSettings = {
steps : 100,
bevelEnabled : false,
extrudePath : closedSpline
};
// Define a triangle
var pts = [], count = 3;
for ( var i = 0; i < count; i ++ ) {
var l = 20;
var a = 2 * i / count * Math.PI;
pts.push( new THREE.Vector2 ( Math.cos( a ) * l, Math.sin( a ) * l ) );
}
var shape = new THREE.Shape( pts );
// Extrude the triangle along the CatmullRom curve
var geometry = new THREE.ExtrudeGeometry( shape, extrudeSettings );
var material = new THREE.MeshLambertMaterial( { color: 0xb00000, wireframe: false } );
// Create mesh with the resulting geometry
var mesh = new THREE.Mesh( geometry, material );
From here, it should only be a matter of small tweaks to these parameters to get the specific road shape you want.
What I'm trying to achieve is a rotation of the geometry around pivot point and make that the new definition of the geometry. I do not want te keep editing the rotationZ but I want to have the current rotationZ to be the new rotationZ 0.
This way when I create a new rotation task, it will start from the new given pivot point and the newly given rad.
What I've tried, but then the rotation point moves:
// Add cube to do calculations
var box = new THREE.Box3().setFromObject( o );
var size = box.getSize();
var offsetZ = size.z / 2;
o.geometry.translate(0, -offsetZ, 0)
// Do ratation
o.rotateZ(CalcUtils.degreeToRad(degree));
o.geometry.translate(0, offsetZ, 0)
I also tried to add a Group and rotate that group and then remove the group. But I need to keep the rotation without all the extra objects. The code I created
var box = new THREE.Box3().setFromObject( o );
var size = box.size();
var geometry = new THREE.BoxGeometry( 20, 20, 20 );
var material = new THREE.MeshBasicMaterial( { color: 0xcc0000 } );
var cube = new THREE.Mesh( geometry, material );
cube.position.x = o.position.x;
cube.position.y = 0; // Height / 2
cube.position.z = -size.z / 2;
o.position.x = 0;
o.position.y = 0;
o.position.z = size.z / 2;
cube.add(o);
scene.add(cube);
// Do ratation
cube.rotateY(CalcUtils.degreeToRad(degree));
// Remove cube, and go back to single object
var position = o.getWorldPosition();
scene.add(o)
scene.remove(cube);
console.log(o);
o.position.x = position.x;
o.position.y = position.y;
o.position.z = position.z;
So my question, how do I save the current rotation as the new 0 rotation point. Make the rotation final
EDIT
I added an image of what I want to do. The object is green. I have a 0 point of the world (black). I have a 0 point of the object (red). And I have rotation point (blue).
How can I rotate the object around the blue point?
I wouldn't recommend updating the vertices, because you'll run into trouble with the normals (unless you keep them up-to-date, too). Basically, it's a lot of hassle to perform an action for which the transformation matrices were intended.
You came pretty close by translating, rotating, and un-translating, so you were on the right track. There are some built-in methods which can help make this super easy.
// obj - your object (THREE.Object3D or derived)
// point - the point of rotation (THREE.Vector3)
// axis - the axis of rotation (normalized THREE.Vector3)
// theta - radian value of rotation
// pointIsWorld - boolean indicating the point is in world coordinates (default = false)
function rotateAboutPoint(obj, point, axis, theta, pointIsWorld){
pointIsWorld = (pointIsWorld === undefined)? false : pointIsWorld;
if(pointIsWorld){
obj.parent.localToWorld(obj.position); // compensate for world coordinate
}
obj.position.sub(point); // remove the offset
obj.position.applyAxisAngle(axis, theta); // rotate the POSITION
obj.position.add(point); // re-add the offset
if(pointIsWorld){
obj.parent.worldToLocal(obj.position); // undo world coordinates compensation
}
obj.rotateOnAxis(axis, theta); // rotate the OBJECT
}
After this method completes, the rotation/position IS persisted. The next time you call the method, it will transform the object from its current state to wherever your inputs define next.
Also note the compensation for using world coordinates. This allows you to use a point in either world coordinates or local space by converting the object's position vector into the correct coordinate system. It's probably best to use it this way any time your point and object are in different coordinate systems, though your observations may differ.
As a simple solution for anyone trying to quickly change the pivot point of an object, I would recommend creating a group and adding the mesh to the group, and rotating around that.
Full example
const geometry = new THREE.BoxGeometry();
const material = new THREE.MeshBasicMaterial({ color: 0xff0000 });
const cube = new THREE.Mesh(geometry, material);
scene.add(cube)
Right now, this will just rotate around its center
cube.rotation.z = Math.PI / 4
Create a new group and add the cube
const group = new THREE.Group();
group.add(cube)
scene.add(group)
At this point we are back where we started. Now move the mesh:
cube.position.set(0.5,0.5,0)
Then move the group
group.position.set(-0.5, -0.5, 0)
Now use your group to rotate the object:
group.rotation.z = Math.PI / 4
I'm trying to re-create an atom with THREE.js, and I'm running into my first issue - since every type of atom has a different amount of Protons/Neutrons, I'm trying to find a way to position them automatically so that there is no collisions, and so the final result of them all together will make something as close to a sphere as possible - see this image for an example
(source: alternativephysics.org)
.
Is there a way to calculate this and assign each Neutron/Protons position easily with a formula? Or will I have to get a physics engine involved to just squeeze the spheres together and hope for the best result with each run?
I don't have any code on this yet, since I'm just trying to figure out where to start with this part.
EDIT
I should also note, that I want the spheres to be squished together within the space of the larger sphere. I am NOT trying to just make all the spheres go on the radius of the larger sphere.
EDIT 2
I looked into using a physics engine to squish them all into a small area, but I can't find an engine that will allow me to move all of the objects in my scene to position (0,0,0) with a gravitational force. All of the engines just make gravity push down on an object. I'd still rather use a formula for positioning the spheres, rather than include an entire physics engine into my project.
EDIT 3, 04/06/06
I've done a bit of experimenting, but I still can't get it right. Here's what it looks like now:
But as you can see, looks really off. This is what happens when I make a Uranium atom instead of a Carbon one (more protons/neutrons/electrons)
It might just be me, but that's looking more like some fancy ratatouille than a Uranium atom.
How I got here:
I was attempting to make what I was looking for up above, and here's the premise:
(particleObject is the parent of particle, the particle will move relative to this object)
I added all protons and neutrons lengths together, so that I could
loop through them all.
If the added number % 2 == 0, (which it is for my testing) I would set the rotate to (pi * 2) / 2 <- last two being there to represent the two above.
Every iteration I would increment l variable. (hopefully) whenever i would equal the loopcount variable, it would mean that I've placed sphere's around in a sphere shape. I'd then multiply loopcount by 3 to find out how many sphere's would be needed for the next run. I'd set l to 0 so that the sphere's positioning would be reset, and the loop would be incremented, causing the next row of sphere's to be placed 1 unit out on the x axis.
(Sorry for the terminology here, it's very hard to explain. See code.)
var PNamount = atomTypes[type].protons + atomTypes[type].neutrons;
var loopcount = 1;
if(PNamount % 2 == 0) {
var rotate = (PI * 2) / 2;
loopcount = 2;
}
var neutrons = 0,
protons = 0,
loop = 1,
l = 0;
for(var i = 0; i < PNamount; i++) {
if(i == loopcount){
loopcount = loopcount * 3;
loop++;
rotate = (PI * 2) / loopcount;
l = 0;
} else {
l++;
}
particleObject.rotation.x = rotate * l;
particleObject.rotation.y = rotate * l;
particleObject.rotation.z = rotate * l;
particle.position.x = loop;
}
Honestly, I'm not that great at all with 3D math. So any help would be really helpful. Plus, it's very possible that my method of positioning them is absolutely wrong in every way. Thanks!
You can see the code live here.
I would definitely say that this is a perfect use case of a physics engine. Making this simulation without a physics engine sounds like a real hassle, so "including an entire physics engine" doesn't seam like such a big cost to me. Most of the JavaScript physics engines that i've found are leight weight anyway. It will however demand some extra CPU power for the physics calculations!
I sat down and tried to create something similar to what you describe with the physics engine CANNON.js. It was quite easy to get a basic simulation working, but to get the parameters just right took is what seems a bit tricky, and will need more adjusting.
You mentioned that you tried this already but couldn't get the particles to gravitate towards a point, with CANNON.js (and probably most other physic engines) this can be achieved be applying a force to the object in the negative position direction:
function pullOrigin(body){
body.force.set(
-body.position.x,
-body.position.y,
-body.position.z
);
}
It is also easy to achieve behaviours where bodies are pulled towards a certain parent object, which in its turn is pull towards the average position of all other parent objects. This way you can create whole molecules.
One tricky thing was to let the electrons circulate the protons and neutrons at a distance. To achieve this I give them a slight force towards the origin, and then a slight force away from all the protons and neutrons at the same time. On top of that I also give them a small push sideways in the beginning of the simulation so that they start circulating the center.
Please let me know if you want me to clarify any particular part.
let scene = new THREE.Scene();
let world = new CANNON.World();
world.broadphase = new CANNON.NaiveBroadphase();
world.solver.iterations = 5;
let camera = new THREE.PerspectiveCamera( 75, window.innerWidth/window.innerHeight, 0.1, 1000 );
let renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
function Proton(){
let radius = 1;
return {
// Cannon
body: new CANNON.Body({
mass: 1, // kg
position: randomPosition(6),
shape: new CANNON.Sphere(radius)
}),
// THREE
mesh: new THREE.Mesh(
new THREE.SphereGeometry( radius, 32, 32 ),
new THREE.MeshPhongMaterial( { color: 0xdd5555, specular: 0x999999, shininess: 13} )
)
}
}
function Neutron(){
let radius = 1;
return {
// Cannon
body: new CANNON.Body({
mass: 1, // kg
position: randomPosition(6),
shape: new CANNON.Sphere(radius)
}),
// THREE
mesh: new THREE.Mesh(
new THREE.SphereGeometry( radius, 32, 32 ),
new THREE.MeshPhongMaterial( { color: 0x55dddd, specular: 0x999999, shininess: 13} )
)
}
}
function Electron(){
let radius = 0.2;
return {
// Cannon
body: new CANNON.Body({
mass: 0.5, // kg
position: randomPosition(10),
shape: new CANNON.Sphere(radius)
}),
// THREE
mesh: new THREE.Mesh(
new THREE.SphereGeometry( radius, 32, 32 ),
new THREE.MeshPhongMaterial( { color: 0xdddd55, specular: 0x999999, shininess: 13} )
)
}
}
function randomPosition(outerRadius){
let x = (2 * Math.random() - 1 ) * outerRadius,
y = (2 * Math.random() - 1 ) * outerRadius,
z = (2 * Math.random() - 1 ) * outerRadius
return new CANNON.Vec3(x, y, z);
}
function addToWorld(object){
world.add(object.body);
scene.add(object.mesh);
}
// create our Atom
let protons = Array(5).fill(0).map( () => Proton() );
let neutrons = Array(5).fill(0).map( () => Neutron() );
let electrons = Array(15).fill(0).map( () => Electron() );
protons.forEach(addToWorld);
neutrons.forEach(addToWorld);
electrons.forEach(addToWorld);
let light = new THREE.AmbientLight( 0x202020 ); // soft white light
scene.add( light );
let directionalLight = new THREE.DirectionalLight( 0xffffff, 0.5 );
directionalLight.position.set( -1, 1, 1 );
scene.add( directionalLight );
camera.position.z = 18;
const timeStep = 1/60;
//Small impulse on the electrons to get them moving in the start
electrons.forEach((electron) => {
let centerDir = electron.body.position.vsub(new CANNON.Vec3(0, 0, 0));
centerDir.normalize();
let impulse = centerDir.cross(new CANNON.Vec3(0, 0, 1));
impulse.scale(2, impulse);
electron.body.applyLocalImpulse(impulse, new CANNON.Vec3(0, 0, 0));
});
function render () {
requestAnimationFrame( render );
// all particles pull towards the center
protons.forEach(pullOrigin);
neutrons.forEach(pullOrigin);
electrons.forEach(pullOrigin);
// electrons should also be pushed by protons and neutrons
electrons.forEach( (electron) => {
let pushForce = new CANNON.Vec3(0, 0, 0 );
protons.forEach((proton) => {
let f = electron.body.position.vsub(proton.body.position);
pushForce.vadd(f, pushForce);
});
neutrons.forEach((neutron) => {
let f = electron.body.position.vsub(neutron.body.position);
pushForce.vadd(f, pushForce);
});
pushForce.scale(0.07, pushForce);
electron.body.force.vadd(pushForce, electron.body.force);
})
// protons and neutrons slows down (like wind resistance)
neutrons.forEach((neutron) => resistance(neutron, 0.95));
protons.forEach((proton) => resistance(proton, 0.95));
// Electrons have a max velocity
electrons.forEach((electron) => {maxVelocity(electron, 5)});
// Step the physics world
world.step(timeStep);
// Copy coordinates from Cannon.js to Three.js
protons.forEach(updateMeshState);
neutrons.forEach(updateMeshState);
electrons.forEach(updateMeshState);
renderer.render(scene, camera);
};
function updateMeshState(object){
object.mesh.position.copy(object.body.position);
object.mesh.quaternion.copy(object.body.quaternion);
}
function pullOrigin(object){
object.body.force.set(
-object.body.position.x,
-object.body.position.y,
-object.body.position.z
);
}
function maxVelocity(object, vel){
if(object.body.velocity.length() > vel)
object.body.force.set(0, 0, 0);
}
function resistance(object, val) {
if(object.body.velocity.length() > 0)
object.body.velocity.scale(val, object.body.velocity);
}
render();
<script src="https://cdnjs.cloudflare.com/ajax/libs/cannon.js/0.6.2/cannon.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r75/three.min.js"></script>
EDIT
I have modularized the particles into a Atom object that can be retrieved from the Atom function. Also added some more comments in the code if your unsure about anything. I would advise you to really study the code, and check the CANNON.js documentation (it is really thourogh). The force related stuff is in the Body class of Cannon.js. All i've done is to combine a THREE.Mesh and a CANNON.Body into a single object (for each particle). Then I simulate all movements on the CANNON.Body, and right before I render the THREE.Mesh, I copy the positions and rotations from CANNON.Body to THREE.Mesh.
This is the Atom function (changed some of the electron physics aswell):
function Atom(nProtons, nNeutrons, nElectrons, pos = new CANNON.Vec3(0, 0, 0)){
//variable to move the atom, which att the particles will pull towards
let position = pos;
// create our Atom
let protons = Array(nProtons).fill(0).map( () => Proton() );
let neutrons = Array(nNeutrons).fill(0).map( () => Neutron() );
let electrons = Array(nElectrons).fill(0).map( () => Electron() );
// Public Functions
//=================
// add to a three.js and CANNON scene/world
function addToWorld(world, scene) {
protons.forEach((proton) => {
world.add(proton.body);
scene.add(proton.mesh);
});
neutrons.forEach((neutron) => {
world.add(neutron.body);
scene.add(neutron.mesh);
});
electrons.forEach((electron) => {
world.add(electron.body);
scene.add(electron.mesh);
});
}
function simulate() {
protons.forEach(pullParticle);
neutrons.forEach(pullParticle);
//pull electrons if they are further than 5 away
electrons.forEach((electron) => { pullParticle(electron, 5) });
//push electrons if they are closer than 6 away
electrons.forEach((electron) => { pushParticle(electron, 6) });
// give the particles some friction/wind resistance
//electrons.forEach((electron) => resistance(electron, 0.95));
neutrons.forEach((neutron) => resistance(neutron, 0.95));
protons.forEach((proton) => resistance(proton, 0.95));
}
function electronStartingVelocity(vel) {
electrons.forEach((electron) => {
let centerDir = electron.body.position.vsub(position);
centerDir.normalize();
let impulse = centerDir.cross(new CANNON.Vec3(0, 0, 1));
impulse.scale(vel, impulse);
electron.body.applyLocalImpulse(impulse, new CANNON.Vec3(0, 0, 0));
});
}
// Should be called after CANNON has simulated a frame and before THREE renders.
function updateAtomMeshState(){
protons.forEach(updateMeshState);
neutrons.forEach(updateMeshState);
electrons.forEach(updateMeshState);
}
// Private Functions
// =================
// pull a particale towards the atom position (if it is more than distance away)
function pullParticle(particle, distance = 0){
// if particle is close enough, dont pull more
if(particle.body.position.distanceTo(position) < distance)
return false;
//create vector pointing from particle to atom position
let pullForce = position.vsub(particle.body.position);
// same as: particle.body.force = particle.body.force.vadd(pullForce)
particle.body.force.vadd( // add particle force
pullForce, // to pullForce
particle.body.force); // and put it in particle force
}
// Push a particle from the atom position (if it is less than distance away)
function pushParticle(particle, distance = 0){
// if particle is far enough, dont push more
if(particle.body.position.distanceTo(position) > distance)
return false;
//create vector pointing from particle to atom position
let pushForce = particle.body.position.vsub(position);
particle.body.force.vadd( // add particle force
pushForce, // to pushForce
particle.body.force); // and put it in particle force
}
// give a partile some friction
function resistance(particle, val) {
if(particle.body.velocity.length() > 0)
particle.body.velocity.scale(val, particle.body.velocity);
}
// Call this on a particle if you want to limit its velocity
function limitVelocity(particle, vel){
if(particle.body.velocity.length() > vel)
particle.body.force.set(0, 0, 0);
}
// copy ratation and position from CANNON to THREE
function updateMeshState(particle){
particle.mesh.position.copy(particle.body.position);
particle.mesh.quaternion.copy(particle.body.quaternion);
}
// public API
return {
"simulate": simulate,
"electrons": electrons,
"neutrons": neutrons,
"protons": protons,
"position": position,
"updateAtomMeshState": updateAtomMeshState,
"electronStartingVelocity": electronStartingVelocity,
"addToWorld": addToWorld
}
}
function Proton(){
let radius = 1;
return {
// Cannon
body: new CANNON.Body({
mass: 1, // kg
position: randomPosition(0, 6), // random pos from radius 0-6
shape: new CANNON.Sphere(radius)
}),
// THREE
mesh: new THREE.Mesh(
new THREE.SphereGeometry( radius, 32, 32 ),
new THREE.MeshPhongMaterial( { color: 0xdd5555, specular: 0x999999, shininess: 13} )
)
}
}
function Neutron(){
let radius = 1;
return {
// Cannon
body: new CANNON.Body({
mass: 1, // kg
position: randomPosition(0, 6), // random pos from radius 0-6
shape: new CANNON.Sphere(radius)
}),
// THREE
mesh: new THREE.Mesh(
new THREE.SphereGeometry( radius, 32, 32 ),
new THREE.MeshPhongMaterial( { color: 0x55dddd, specular: 0x999999, shininess: 13} )
)
}
}
function Electron(){
let radius = 0.2;
return {
// Cannon
body: new CANNON.Body({
mass: 0.5, // kg
position: randomPosition(3, 7), // random pos from radius 3-8
shape: new CANNON.Sphere(radius)
}),
// THREE
mesh: new THREE.Mesh(
new THREE.SphereGeometry( radius, 32, 32 ),
new THREE.MeshPhongMaterial( { color: 0xdddd55, specular: 0x999999, shininess: 13} )
)
}
}
function randomPosition(innerRadius, outerRadius){
// get random direction
let x = (2 * Math.random() - 1 ),
y = (2 * Math.random() - 1 ),
z = (2 * Math.random() - 1 )
// create vector
let randVec = new CANNON.Vec3(x, y, z);
// normalize
randVec.normalize();
// scale it to the right radius
randVec = randVec.scale( Math.random() * (outerRadius - innerRadius) + innerRadius); //from inner to outer
return randVec;
}
And to use it:
let scene = new THREE.Scene();
let world = new CANNON.World();
world.broadphase = new CANNON.NaiveBroadphase();
world.solver.iterations = 5;
let camera = new THREE.PerspectiveCamera( 75, window.innerWidth/window.innerHeight, 0.1, 1000 );
let renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
// create a Atom with 3 protons and neutrons, and 5 electrons
// all circulating position (-4, 0, 0)
let atom = Atom(3, 3, 5, new CANNON.Vec3(-4, 0, 0));
// move atom (will not be instant)
//atom.position.x = -2;
// add to THREE scene and CANNON world
atom.addToWorld(world, scene);
let light = new THREE.AmbientLight( 0x202020 ); // soft white light
scene.add( light );
let directionalLight = new THREE.DirectionalLight( 0xffffff, 0.5 );
directionalLight.position.set( -1, 1, 1 );
scene.add( directionalLight );
camera.position.z = 18;
const timeStep = 1/60;
// give the atoms electrons some starting velocity
atom.electronStartingVelocity(2);
function render () {
requestAnimationFrame( render );
// calculate all the particles positions
atom.simulate();
// Step the physics world
world.step(timeStep);
//update the THREE mesh
atom.updateAtomMeshState();
renderer.render(scene, camera);
};
render();
I have been facing the same problem, and also made a solution using Cannon.js. However, when rendering heavier elements this might cause a considerable load, especially on mobile.
I came up with an idea to capture the final position of the nucleons after they have settled and save that in a json file for all the elements.
Then the nucleons can be made to orbit the nucleus linearly without physics.
one solution would be to use the icosphere algorithm to calculate the position of a Neutrons/Protons using the vertex point of generated sphere.
You can find ad usefoul algorithm here
the distance between the points remains equal over the entire surface
Hi folks,
I've got a question belongig surfaces in Three.js:
I got a bunch of Vec3 Points and want want to interpolate a surface through them. While searching, I stumbeled across beziers (three.js bezier - only as lines) and what looked more like I was searching : three.js Nurbs. I've tried to reconstruct the code, but the documentation was terrible (pages like this) and I didn't get how everything worked by reconstructing the code...
So here's the question:
Is there any easy way to get a shape out of my calculated points? (I would still be happy, if it's not interpolated).
Thank you guys!
Mat
Edit: What I want to acchieve is a surface plot. I stumbeled across http://acko.net/blog/making-mathbox/ but it's way too big for my needs...
After some try and error I found a solution: add a plane and than transform the single vertices.
// need to setup 'step', 'xStart', 'xEnd', 'yStart', 'yEnd'
// calc the variables
var width = Math.abs(-xStart+xEnd),
height = Math.abs(-yStart+yEnd);
var stepsX = width*step, stepsY = height*step;
var posX = (xStart+xEnd)/2;
var posZ = (yStart+yEnd)/2;
// add a plane and morph it to a function
var geometry = new THREE.PlaneGeometry( width, height, stepsX - 1, stepsY - 1 );
geometry.applyMatrix( new THREE.Matrix4().makeRotationX( - Math.PI / 2 ) );
var size = stepsX * (stepsY),
data = new Float32Array( size );
var count = 0, scope = {};
mesh = new THREE.Mesh( geometry, new THREE.MeshNormalMaterial( {
side : THREE.DoubleSide,
transparent: true,
shading: THREE.SmoothShading,
opacity : _opacity }));
mesh.updateMatrixWorld();
// calc y value for every vertice
for ( var i = 0; i < size; i ++ ) {
// calculate the current values
// http://stackoverflow.com/questions/11495089/how-to-get-the-absolute-position-of-a-vertex-in-three-js
var vector = mesh.geometry.vertices[i].clone();
vector.applyMatrix4(
mesh.matrixWorld
);
// set them into the scope
scope.x = vector.x + posX;
scope.y = vector.z + posZ;
// calculate point and write it in a temp array
data[i] = math.eval(term, scope);
}
// push the new vertice data
for ( var i = 0, l = geometry.vertices.length; i < l; i ++ ) {
geometry.vertices[ i ].y = data[ i ];
}
// update the new normals
geometry.computeFaceNormals();
geometry.computeVertexNormals();
// add to scene
scene.add( mesh );
Only issue is that it is not working for non static functions like tan(x). This snippet is using math.js to calc the term.
Greetings Mat