I need help with drawing in Babylon js

[Maria D]

Hi! I'm trying to learn Babylon js and it's my first time using it ☺️.

I'm doing a kind of planetary system and the planet's movement can be changed using a slider. I also draw a circle made with lines (the orbit) to show the path followed by the planet when the slider also changes. But I have problem: I don't know how to remove the  previous drawn circle. So as a result when the planet changes its orbit, many circles are still drawn.

Something like this:

Here is a part of my code inside createScene function:

 

//Creation of slider

var slider = new BABYLON.GUI.Slider();

slider.minimum = 0;

slider.maximum = 1;

slider.value = 0;

slider.paddingRight="10";

slider.horizontalAlignment= BABYLON.GUI.Control.HORIZONTAL_ALIGNMENT_RIGHT;

slider.height = "20px";

slider.width = "200px";

slider.top="10";

slider.color="blue";

for(var i = 0; i < div; i++){

divArray.push(Math.PI*(MitadDiv*i));

}

slider.onValueChangedObservable.add(function(value) {

 

e = value;

a = Math.sqrt(-(b*b)/((e*e)-1));

text.text = "Excentricidad: "+(value);

for(var i = 0; i < divArray.length; i++){

Path.push(new BABYLON.Vector3((b * Math.cos(divArray[i])+offset.x), (0+offset.y), (a * Math.sin(divArray[i])+offset.x)));

}

var lines = BABYLON.MeshBuilder.CreateDashedLines("lines", {points: Path, dashNb:500}, scene);

 

});

guiManager.addControl(slider);

 

scene.beforeRender = function () {

 

planet.position = new BABYLON.Vector3((b * Math.cos(Math.PI*(MitadDiv*alpha))+offset.x), (0+offset.y), (a * Math.sin(Math.PI*(MitadDiv*alpha))+offset.x));

sun.rotate(BABYLON.Axis.Y, Math.sin(-0.001), BABYLON.Space.WORLD);

planet.rotate(BABYLON.Axis.Y, Math.sin(2 * -Math.PI/180), BABYLON.Space.WORLD);

alpha += 0.09;

 

 

};

 

 

 

 

 

return scene;

Thanks!!!

 

 

[8Observer8]

Hello, Maria. I think it is better to use the native forum for BabylonJS: https://forum.babylonjs.com/