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Odd looking after-scaling issue


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I've got a strange looking render order issue. The "original", non-scaled object(s) appear fine. They render correctly as I might expect. See before-scaling image.

However, I applied a scaling about the Z axis (new Vector3(1,1,-1)), and it got all wonky. Almost like the render order was out of wack. See after-scaling image.

How do I tell the scene which order to render? Or better yet, how to group them so that it's a non-issue?

Thank you...



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For reference, I am doing something like this to apply my scaling, but honestly, I do not know how that would be any different? This is not any different when I set the default identity; only with the Vector3(1,1,-1) I get the odd rendering issue.

/* this is my GoalPost model replete with calculations for points etc. */
this.children = [
    , this.padding
    , this.arch
    , this.crossBar
    , this.leftUpright
    , this.rightUpright

/* gets the scaling obtained from GoalPost; set, or "default" to "identity", or Vector3(1,1,1) */
var scaling = this.getScaling();

/* each() is an extension method I attached on Array.prototype. */
this.children.each(function (x) { x.scaling = scaling; })


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Hi guys!  *nod*  Negative scaling... that's unhealthy.  That's been known to make mesh do strange things.  :)  We lost a forum user one time, when he accidentally used negative scaling values, and his computer room turned inside-out.  :D  Try to avoid using negative values for scaling (unless you are a mad scientist who likes torturing webGL).

To add-on to Adam's fine-but-short answer:

var parentMesh = new BABYLON.Mesh('groupwidget', scene);  (how to make an empty mesh to use for all children.parent).  Pretty easy.  You can still maintain a list of parentMesh.children[] but make sure you iterate thru them... and set each.parent = parentMesh; 

We also have a "tags system" that let's you do some fancy wildcard-match "gathering" of specific tag-groups from the scene.meshes array.

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This sort of scaling works just fine rendering from Helix Toolkit for WPF. Probably an unfair comparison, I'll grant you.

@Wingnut Avoidance is fine, fair enough; but do you have any suggestions? Being the lazy developer that I am, I want to calculate things smart, ONCE.

@Temechon Obviously. Suggestions?

If I were to establish a non-zero field origin, let's say, is there a method that transforms or "rotates" about a non-zero origin, for instance?

Thank you...

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24 minutes ago, mwpowellhtx said:

Thanks for the tip. That's secondary to the rendering issue, but I am concerned this might be a little deeper than gathering meshes in a JavaScript array.

What array?

You then scale the parent and it scales all the children.

Parenting is how you group meshes in BJS.

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@Wingnut At the moment, yes, "field" is the parent object, with goal posts on one end (original), and another, to be modeled, then "rotated".

Currently, I assume absolute origin (0,0,0) is center/center field, if you will; all the calculations for goal posts, lines, etc, just work out real easy.

But if I were to calculate relative to world (or field) origin, wouldn't be much different, I expect.

So, what's the BABYLON primitive(s)?

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1 minute ago, adam said:

What array?

You then scale the parent and it scales all the children.

I see; my "parent" is not a mesh object, per se; it's just a calculator, per se, with some mesh children captured in a prototype variable. Does that make sense?

If possible, yes, I might like to "extend" a mesh prototype. "Base class"?

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hahahaha.  Adam, you're too funny!

But yeah, I am starting to think that @mwpowellhtx is... umm... a mad scientist.  ;)

There are two types of people in the world.  #1 - Those that follow the direction of the big neon arrow.  #2 - Those that disassemble big neon arrows... to discover what makes them point.

I suspect that mw is a type #2.  :)

By the way, would you like to learn the "down and dirty" way to move pivot points?

Move mesh sideways 20 units.
move mesh back to origin

Done.  mesh now has an offset pivot point.  Fun, huh? 

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It's turning into a bit of a rabbit hole, which is fine is this is the right way to go about it. I bumped into a couple of errors needing to fill in some gaps, such as getTotalVertices, isReady, isEnabled; all fairly benign, it would seem.

Element.prototype.getTotalVertices = function() {
    return this._children.sum(function (c) {
        return c.getTotalVertices();

Element.prototype.isReady = function() {
    return this._children.all(function (c) {
        return c.isReady();

// perhaps should be connecting with children?
Element.prototype._enabled = true;

Element.prototype.isEnabled = function() {
    return this._enabled;

Element.prototype.setEnabled = function (state) {
    this._enabled = state || false;
    return this;

However, now I am stumped on a computeWorldMatrix, which I haven't got a clue about, except to say, that instead of keeping track of _children, per se, perhaps I should be using the BABYLON.Mesh.MergeMeshes function in order to merge the parts of my models into a single cohesive mesh.

So, first assumption, that I should inherit from BABYLON.Mesh? Yes, no, maybe?

And/or if not, then how else?

With the backdrop being the odd looking scaling going on. That's before jumping into any world coordinate systems, which maybe I need to do anyhow.

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