Bounding box bug?

Questions
1

Hi,

I want to calculate the bounding box in this simple example:

As you can see, the bounding box is well designed but its min and max world coordinates do not fit the drawing and i don’t know why.

I’ve draw a line between the min and max coordinates to show you what happens.

Is this a bug or a mistake i’ve done ?

Thanks for your help,

Boris

2

Hi,

It’s because box worldMatrix has not been updated when you draw the line.

You may either draw the line next frame, or call

box.computeWorldMatrix(true)

Before you get your line positions.

3

I am facing the same problem but the computation of WorldMatrix does not solves my problem : https://playground.babylonjs.com/#ZIUHK6#10

4

Hi @SvenFrankson,

I’ve done what you told me but it’s not well either.

Now my minimumWorld is [0,0,0] and my MaximumWorld is [10,15,5]. It would be correct if my box was not rotated and translated.

if I call box.computeWorldMatrix(true) after the displacement and rotation of my box, my minimumWorld is [X: 1.0000000894069672 Y: 0 Z: -7.071067720651627] and my maximumWorld is [X: 11.606601625680923 Y: 15 Z: 3.5355338156223297] which fits to the red cube in my PG but which is not correct.

Here’s the PG :https://playground.babylonjs.com/#RA67AR#5

I mean that the boundingbox min and max world values should fit to the real bounding box.

I’m sure i’ve done an error but i’m a little bit lost.

5

The boundingBox property is a axis-aligned bounding box, not an object aligned one, so it will only fit perfectly if the rotations are multiples of 90 degrees:
image

If you need to compute the object aligned box I’d bake the transform in the object and compute the BB again

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