Box3 expandByObject fails if attribute.itemSize is 2.

Box3’s expandByObject fails for buffer geometry whose itemSize !== 3.

If you call expandByObject(obj) where obj has a child with (for example) a TextGeometry, this line will attempt to read past the end of an array, then call applyMatrix4 so that v1 is {x:NaN, y:NaN, z:NaN}: https://github.com/mrdoob/three.js/blob/master/src/math/Box3.js#L255 This means that the box’s min and max both become NaN, NaN, NaN.

One (obviously not optimized) solution is to replace that line with:

if (attribute.itemSize === 2) {
  var v2 = new Vector2();
  v2.fromBufferAttribute(attribute, i);
  v1.x = v2.x;
  v1.y = v2.y;
  v1.z = 0;
} else {
   v1.fromBufferAttribute(attribute, i);
}
v1.applyMatrix4(node.matrixWorld);

Of course, this would fail if attribute.itemSize === 4. (I’m not sure ever happens in practice.) You can fix that by checking if itemSize ===3 before reading from it with a Vector3.

This is not a problem with setFromBufferAttribute because that does not rely on Math.min or Math.max, which favor NaN over any numbers. (Instead it uses < and > which favor numbers over NaN.)

Three.js version

• Dev
• r93
• …

Browser

• All of them
• Chrome
• Firefox
• Internet Explorer

OS

• All of them
• Windows
• macOS
• Linux
• Android
• iOS

Hardware Requirements (graphics card, VR Device, …)

[Mugen87]

In this case I vote to clarify the documentation. Users have to ensure their geometry data is expressed in 3D space when using Box3.

[Usnul]

I see. So WebGL renderer makes that assumption. Okay, I won’t argue further.