What code are you using to load the scene.

Three.js for web games or mobile/desktop games?

Three.js for webGame.

Here is my code to load 3DScene :

app.js

var INITIALISED = false;

var HelloWorldLayer = cc.Layer.extend({
    _mainscene:null,
    _size:null,
    ctor:function () {

        this._super();


        this._size = cc.winSize;

        this._mainscene = ccs.load(res.MenuScene_json);
        this.addChild(this._mainscene.node);

       /* var camera = cc.Camera.createPerspective(60,size.width/size.height,1,1000);
        camera.setPosition3D(Vec3(0,100,100));
        camera.lookAt(Vec3(0,0,0),Vec3(0,1,0));
        this.addChild(camera);*/

        var btn = this._mainscene.node.getChildByName("btn_Start");
        btn.addTouchEventListener(this.touchEvent,this);


        return true;
    },
    touchEvent: function(sender, type)
    {
        var scene = new Scene3D();
        switch(type)
        {
            case ccui.Widget.TOUCH_ENDED:
                cc.director.pushScene(scene);
        }
    }
});

var HelloWorldScene = cc.Scene.extend({
    onEnter:function () {
        this._super();
        if(INITIALISED == false)
        {
            INITIALISED = true;
            var layer = new HelloWorldLayer();
            this.addChild(layer);
        }
    }
});

3dScene.js

var INITIALISED_3D = false;

var Scene3DLayer = cc.Node.extend({
    _scene:null,
    _size:null,
    ctor:function () {

        this._super();


        this._size = cc.winSize;

        this._scene = ccs.load(res.Scene3D_json);
        this.addChild(this._scene.node);

        console.log(this);

        /* var camera = cc.Camera.createPerspective(60,size.width/size.height,1,1000);
         camera.setPosition3D(Vec3(0,100,100));
         camera.lookAt(Vec3(0,0,0),Vec3(0,1,0));
         this.addChild(camera);*/

        return true;
    }

});

var Scene3D = cc.Scene.extend({
    onEnter:function () {
        this._super();
        if(INITIALISED_3D == false)
        {
            INITIALISED_3D = true;
            var layer = new Scene3DLayer();
            this.addChild(layer);
        }
    }
});

Have you looked at the examples in the Cocos2d-x folder?

Yes but there is no example for launching a 3d scene in javascript

Are there any examples for launching a scene in C++?

There : http://cocos2d-x.org/documentation/programmers-guide/9/index.html

but some function does not exist when i try but convert the code in javascript.

I did not find any other example.

What function does not exist?

The functions that does not exist are for creating a camera in javascript.

But,

That is not what I asked, can you answer me something instead of answering me another question please? It’s not usefull right now. I juste want to launch a 3d scene in javascript, did you already done that ? I sent you my code, what is wrong with it? and for Three.js, is there any way to use it in the same canvas than cocos?

Does a model load correctly.

Three.js can be potentially used with Cocos but no point, just use Three.js if you want Three.js.

No I can’t load any model, when I have a model in my scene, I get this error : 

loader for [.c3t] not exists!

What version of cocos are you using?

I am using cocos2d-x-3.10

What 3D model was you trying to load?

A simple cube...

Have you tried one of the included models from the Cocos Examples?

Yes, I got the same issue

That is weird, try it in a fresh project using the code from our Cocos API Guide http://cocos.sonarlearning.co.uk/