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Determine Ray destination


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Hiya @richardsmd, welcome to the forum.


Sorry for the slow replies.  I think line 22... might be of-interest to you.  :)  Hope this helps.  Holler if you need more help.  Babylon Playground searcher reports 946 hits... when searching for 'Ray'.  Plenty of various examples to tour.   Be well, party on!

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I (perhaps incorrectly) conceptualize a ray as an origin point and a direction. Without a length the ray extends infinitely from it's origin, but a ray with a length has a constrained endpoint/destination. After I was clued into the existence of RayHelper I easily located the code:

var endPoint = ray.origin.add(ray.direction.scale(ray.length))

Perhaps I should explain why I even want this...

I'm trying to add additional movement controls to a freecamera. What I'd like to do is set scroll up/down to "jump" the camera some distance (say, 20 units) exactly along it's current path. Given the camera object, the easiest way I can think to do this is

I was expecting to discover how to do this in Scene.pickWithRay. I followed the code as far as AbstractMesh.intersects, but now get the impression that I've incorrectly conceptualized how Ray's are used.

@adam linked a playground demonstrating how to render a ray with a RayHelper. I found this in RayHelper.show which in conjunction with this playground (lines 38-42) that @Deltakosh provided in this post led to the following...


/** Jump camera forward/backward in reaction to WheelEvent.
* @param {WheelEvent} e - the event. Must contain wheelDelta property.
function onWheel(e) {
    let cam = scene.activeCamera;

    let invView = new Babylon.Matrix();
    let direction = Babylon.Vector3.TransformNormal(Babylon.Vector3.Forward(), invView);

    // Go "backwards" on wheel down
    if (e.wheelDelta < 0) {

canvas.addEventListener("mousewheel", onWheel);

Thank you all very much for your assistance!


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