In ThreeJS, it is possible to add more than one material to an Object3D/Mesh according to its documentation. We can use a single Material or use an array of Material:
Mesh typescript file class declaration and contructor (from ThreeJS src code):
export class Mesh<
TGeometry extends BufferGeometry = BufferGeometry,
TMaterial extends Material | Material[] = Material | Material[] // ### Here: Material[] ###
> extends Object3D {
constructor(geometry?: TGeometry, material?: TMaterial);
Here is my problem which I can't seem to be able to solve...
When I use a single Material, my Mesh is displayed. However, when I use two materials as an array, my Mesh won't display. I also don't have any error print out in the console when rendering the scene.
My ultimate goal here is to be able to have to separate materials for the inner and the outer part of my object.
Here is my code:
export function init(radius: number = 18.0, innerColor: number = 0xFFFFFF, outerColor: number = 0x444444) {
var obj = new Object3D();
loader.load(
objPath,
function(object){
obj = object;
const mesh = obj.children[0] as Mesh;
// WORKING:
mesh.material = new MeshPhongMaterial({color: outerColor});
// NOT WORKING: Using two materials
// mesh.material = new Array<Material>(new MeshPhongMaterial({color: outerColor}), new MeshPhongMaterial({color:innerColor}));
mesh.scale.setLength(radius)
scene.add(mesh);
},
function (error){
console.log(error)
}
);
}
Why can't I manage to see my object when using two materials ?
I known there was the MeshFaceMaterial in previous version and the material array acceptance of the contructor is supposed to be a replacement for that in some sens.
ThreeJS version: r128
Any help would be appreciated !
The easiest way is to clone your mesh and assign two separate materials, one for the inside, another for the outside:
const meshOuter = obj.children[0] as THREE.Mesh;
const meshInner = meshOuter.clone();
// Outer mesh shows front side
meshOuter.material = new THREE.MeshPhongMaterial({
color: outerColor,
side: THREE.FrontSide
});
// Inner mesh shows back side
meshInner.material = new THREE.MeshPhongMaterial({
color: innerColor,
side: THREE.BackSide
});
// Scale inner mesh down just a bit to avoid z-fighting
meshInner.scale.multiplyScalar(0.99);
I was exploring THREE.js & was trying different geometries in it. So as it has a whole lot of geometries writing every single one manually is too boring.
I would have to write these lines for a simple cube to be displayed:
var material = new THREE.MeshNormalMaterial();
var boxGeometry = new THREE.BoxGeometry( 20, 20, 20 );
var box = new THREE.Mesh( boxGeometry, material );
box.position.set(-10, -10, 0);
scene.add( box );
To add another one say a cone i would have to just copy paste the above lines & then replace Box with Cone & you know that's my computer's work (not mine). Humans are not made for copying :)
So i wanted a general class after which i can say something like:
var cube = new Shape('Cube', 20, 20, 20);
// or
var cone = new Shape('Cone', 20, 30);
& that may do everything else for me, i can extract the arguments from the function but then what to do?
Say how to convert them from strings to logical statements?
With bracket notation, you can make a function that accesses Three.<word>Geometry, while using rest syntax to collect the other arguments, and then spread them into the constructor:
function makeShape(shapeName, ...args) {
var material = new THREE.MeshNormalMaterial();
var boxGeometry = new THREE[shapeName + 'Geometry'](...args);
var box = new THREE.Mesh( boxGeometry, material );
box.position.set(-10, -10, 0);
scene.add( box );
}
Then, just call that function:
makeShape('Cube', 20, 20, 20);
makeShape('Cone', 20, 30);
If you want to assign something created in the function to the caller of makeShape, just return it at the end.
So I have some lovely JSON exported from Blender using three.js' addon. Works great.
I want to grab colours from each of the materials that the geometry has been exported with and change their material types to "point."
This again works fine according to my console output of the model.material array before and after my .forEach.
Unfortunately, nothing is displayed, as though no material has been applied whatsoever.
As per the inline comment below, a single colour material does work, as do the original materials loaded from the JSON.
var loader = new THREE.JSONLoader();
var model = loader.parse(json from elsewhere);
var mesh;
var pointMats = [];
model.materials.forEach(function(j) {
var color = new THREE.Color(j.color.r, j.color.g, j.color.b);
var specular = new THREE.Color(j.specular.r, j.specular.g, j.specular.b);
var newPointsMat = new THREE.PointsMaterial({
name: j.name,
color: color,
lights: true,
size: 1
});
pointMats.push(newPointsMat);
});
// var pointsMat = new THREE.PointsMaterial( {
// color: 0xffffff,
// size: 0.01
// }); // this works fine and is applied to all the meshes in my scene
mesh = new THREE.Points(model.geometry, pointMats);
scene.add(mesh);
Of course, no errors are given in the console. Probably because there isn't an error to be displayed.
Thanks for your time
THREE.Points accepts a single instance of Material and can't handle an array of them on a single mesh.
I created a three js object and added some children to it. then i changed the length of children to 0. then the objects have gone out of screen. Will that make the objects fully removed from the screen and memory?
var balls = new THREE.Object3D(); // parent
for creating childrens
var geometry = new THREE.SphereGeometry(5, 32, 32);
var material = new THREE.MeshPhongMaterial({color: 0x0f0ff0, shininess: 50, transparent: true, opacity: 1});
var sphere = new THREE.Mesh(geometry, material);
sphere.position.x = scale('some random value');
sphere.position.y = scale('some random value');
balls.add(sphere);
above steps repeated for more spheres
then in the console i wrote
balls.children = [];
this removes all the spheres from the scene. Will that removes all the sphere objects from the memory also??
Yes, when you have an array and then set array.length = 0; all the elements of the array will be deleted. When you type array.length = 2, all elements other than the first two elements will be deleted.
Javascript has a function called slice() which does a similar thing.
The correct way for deleting a child is calling remove(child) from its parent, and then use dispose() on children's material and geometry.
In your code:
var balls = new THREE.Object3D(); // parent
var geometry = new THREE.SphereGeometry(5, 32, 32);
var material = new THREE.MeshPhongMaterial({color: 0x0f0ff0, shininess: 50, transparent: true, opacity: 1});
var sphere = new THREE.Mesh(geometry, material);
sphere.position.x = scale('some random value');
sphere.position.y = scale('some random value');
balls.add(sphere);
// Do some work
balls.remove(sphere);
geometry.dispose();
material.dispose();
Dispose the material/geometry only when it is not used by other Mesh anymore.
From THREE.Object3D at remove(object, ...):
"Removes object as child of this object. An arbitrary number of objects may be removed."
From THREE.Geometry at dispose():
"Don't forget to call this method when you remove a geometry because it can cause memory leaks."
From THREE.Material at dispose():
"This disposes the material. Textures of a material don't get disposed. These needs to be disposed by Texture."
If you use textures, you must dispose these too.
(THREE.js r85).
Here I bumped to the problem since I need to merge two geometries (or meshes) to one. Using the earlier versions of three.js there was a nice function:
THREE.GeometryUtils.merge(pendulum, ball);
However, it is not on the new version anymore.
I tried to merge pendulum and ball with the following code:
ball is a mesh.
var ballGeo = new THREE.SphereGeometry(24,35,35);
var ballMat = new THREE.MeshPhongMaterial({color: 0xF7FE2E});
var ball = new THREE.Mesh(ballGeo, ballMat);
ball.position.set(0,0,0);
var pendulum = new THREE.CylinderGeometry(1, 1, 20, 16);
ball.updateMatrix();
pendulum.merge(ball.geometry, ball.matrix);
scene.add(pendulum);
After all, I got the following error:
THREE.Object3D.add: object not an instance of THREE.Object3D. THREE.CylinderGeometry {uuid: "688B0EB1-70F7-4C51-86DB-5B1B90A8A24C", name: "", type: "CylinderGeometry", vertices: Array[1332], colors: Array[0]…}THREE.error # three_r71.js:35THREE.Object3D.add # three_r71.js:7770(anonymous function) # pendulum.js:20
To explain Darius' answer more clearly (as I struggled with it, while trying to update a version of Mr Doob's procedural city to work with the Face3 boxes):
Essentially you are merging all of your Meshes into a single Geometry. So, if you, for instance, want to merge a box and sphere:
var box = new THREE.BoxGeometry(1, 1, 1);
var sphere = new THREE.SphereGeometry(.65, 32, 32);
...into a single geometry:
var singleGeometry = new THREE.Geometry();
...you would create a Mesh for each geometry:
var boxMesh = new THREE.Mesh(box);
var sphereMesh = new THREE.Mesh(sphere);
...then call the merge method of the single geometry for each, passing the geometry and matrix of each into the method:
boxMesh.updateMatrix(); // as needed
singleGeometry.merge(boxMesh.geometry, boxMesh.matrix);
sphereMesh.updateMatrix(); // as needed
singleGeometry.merge(sphereMesh.geometry, sphereMesh.matrix);
Once merged, create a mesh from the single geometry and add to the scene:
var material = new THREE.MeshPhongMaterial({color: 0xFF0000});
var mesh = new THREE.Mesh(singleGeometry, material);
scene.add(mesh);
A working example:
<!DOCTYPE html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r77/three.js"></script>
<!-- OrbitControls.js is not versioned and may stop working with r77 -->
<script src='http://threejs.org/examples/js/controls/OrbitControls.js'></script>
<body style='margin: 0px; background-color: #bbbbbb; overflow: hidden;'>
<script>
// init renderer
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
// init scene and camera
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.01, 3000);
camera.position.z = 5;
var controls = new THREE.OrbitControls(camera)
// our code
var box = new THREE.BoxGeometry(1, 1, 1);
var sphere = new THREE.SphereGeometry(.65, 32, 32);
var singleGeometry = new THREE.Geometry();
var boxMesh = new THREE.Mesh(box);
var sphereMesh = new THREE.Mesh(sphere);
boxMesh.updateMatrix(); // as needed
singleGeometry.merge(boxMesh.geometry, boxMesh.matrix);
sphereMesh.updateMatrix(); // as needed
singleGeometry.merge(sphereMesh.geometry, sphereMesh.matrix);
var material = new THREE.MeshPhongMaterial({color: 0xFF0000});
var mesh = new THREE.Mesh(singleGeometry, material);
scene.add(mesh);
// a light
var light = new THREE.HemisphereLight(0xfffff0, 0x101020, 1.25);
light.position.set(0.75, 1, 0.25);
scene.add(light);
// render
requestAnimationFrame(function animate(){
requestAnimationFrame(animate);
renderer.render(scene, camera);
})
</script>
</body>
At least, that's how I am interpreting things; apologies to anyone if I have something wrong, as I am no where close to being a three.js expert (currently learning). I just had the "bad luck" to try my hand at customizing Mr. Doob's procedural city code, when the latest version breaks things (the merge stuff being one of them, the fact that three.js no longer uses quads for cube -ahem- box geometry the other - which has led to all kinds of fun getting the shading and such to work properly again).
Finally, I found a possible solution. I am posting since it could be useful for somebody else while I wasted a lot of hours. The tricky thing is about manipulating the concept of meshes and geometries:
var ballGeo = new THREE.SphereGeometry(10,35,35);
var material = new THREE.MeshPhongMaterial({color: 0xF7FE2E});
var ball = new THREE.Mesh(ballGeo, material);
var pendulumGeo = new THREE.CylinderGeometry(1, 1, 50, 16);
ball.updateMatrix();
pendulumGeo.merge(ball.geometry, ball.matrix);
var pendulum = new THREE.Mesh(pendulumGeo, material);
scene.add(pendulum);
The error message is right. CylinderGeometry is not an Object3D. Mesh is. A Mesh is constructed from a Geometry and a Material. A Mesh can be added to the scene, while a Geometry cannot.
In the newest versions of three.js, Geometry has two merge methods: merge and mergeMesh.
merge takes a mandatory argument geometry, and two optional arguments matrix and materialIndexOffset.
geom.mergeMesh(mesh) is basically a shorthand for geom.merge(mesh.geometry, mesh.matrix), as used in other answers. ('geom' and 'mesh' being arbitrary names for a Geometry and a Mesh, respectively.) The Material of the Mesh is ignored.
This is my ultimate compact version in four (or five) lines (as long as material is defined somewhere else) making use of mergeMesh:
var geom = new THREE.Geometry();
geom.mergeMesh(new THREE.Mesh(new THREE.BoxGeometry(2,20,2)));
geom.mergeMesh(new THREE.Mesh(new THREE.BoxGeometry(5,5,5)));
geom.mergeVertices(); // optional
scene.add(new THREE.Mesh(geom, material));
Edit: added optional extra line to remove duplicate vertices, which should help performance.
Edit 2: I'm using the newest version, 94.
The answers and code that I've seen posted here do not work because the second argument of the merge method is an integer, not a matrix. As far as I can tell, the merge method is not really functioning in a useful way. Therefore, I used the following approach to make a simple rocket with a nose cone.
import * as BufferGeometryUtils from '../three.js/examples/jsm/utils/BufferGeometryUtils.js'
lengthSegments = 2
radius = 5
radialSegments = 32
const bodyLength = dParamWithUnits['launchVehicleBodyLength'].value
const noseConeLength = dParamWithUnits['launchVehicleNoseConeLength'].value
// Create the vehicle's body
const launchVehicleBodyGeometry = new THREE.CylinderGeometry(radius, radius, bodyLength, radialSegments, lengthSegments, false)
launchVehicleBodyGeometry.name = "body"
// Create the nose cone
const launchVehicleNoseConeGeometry = new THREE.CylinderGeometry(0, radius, noseConeLength, radialSegments, lengthSegments, false)
launchVehicleNoseConeGeometry.name = "noseCone"
launchVehicleNoseConeGeometry.translate(0, (bodyLength+noseConeLength)/2, 0)
// Merge the nosecone into the body
const launchVehicleGeometry = BufferGeometryUtils.mergeBufferGeometries([launchVehicleBodyGeometry, launchVehicleNoseConeGeometry])
// Rotate the vehicle to horizontal
launchVehicleGeometry.rotateX(-Math.PI/2)
const launchVehicleMaterial = new THREE.MeshPhongMaterial( {color: 0x7f3f00})
const launchVehicleMesh = new THREE.Mesh(launchVehicleGeometry, launchVehicleMaterial)