Create a box that exactly matches the bounding box after rotation

Questions
1

Hi. I would like to create a box every end of gizmo rotation. The box should exactly match the actual geometry bounding box after each rotation.

Here is the PG I created: https://playground.babylonjs.com/#4F33I3#632
I wrote some code comments that didn’t work well, but maybe it might help to find a solution. Thank you for your attention

2

You’re looking for an Object-Oriented Bounding Box (OBB) in opposite to the Axis-Aligned (AABB) Bounding Box that we calculate:

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3

The axis aligned bounding box is enough for me. Actually, I need to create a box mesh that matches the AABB of the other object, even if I rotate the object. I will use this box to do a simple csg and delete the box. The AABB already rotates perfectly according to my expectations but I cant make the box fit the bounding box of the merged mesh

4

If you just need the AABB, then the bounding box of a Mesh: BoundingBox | Babylon.js Documentation (babylonjs.com) should have all the information you need, and you can obtain it with getBoundingInfo(). One important detail is to ensure the world matrix is updated when you get it, by calling computeWorldMatrix with the force parameter set to true: Bounding boxes | Babylon.js Playground (babylonjs.com)

5

I could improve the code by hit and try since I am not sure which vector I am taking from the bounding info: https://playground.babylonjs.com/#4F33I3#633
And also I have to get the right angle to rotate the box. I feel that what I did was not right. Could you check if the line 54 makes sense? I had to add a correction factor (1.1) BABYLON.Vector3.GetAngleBetweenVectors(merged.getBoundingInfo().boundingBox.vectorsWorld[0],new BABYLON.Vector3(1,0,0),BABYLON.Vector3.Cross(extend.boundingBox.vectorsWorld[0], new BABYLON.Vector3(1,0,0)));

6

Have you tried using extendSizeWorld like my playground example?

7

I have tried the extendsizeWorld like in the first PG. If I use this vector, I have to get the components x y and z like the example you showed me. As I rotate, these components behave like a sinusoidal function. The box mesh would not fit the boundingbox after rotation

8

I found a solution for the angle:
var normalfacebounding = BABYLON.Vector3.Cross(merged.getBoundingInfo().boundingBox.vectorsWorld[2].subtract(merged.getBoundingInfo().boundingBox.vectorsWorld[1]),merged.getBoundingInfo().boundingBox.vectorsWorld[5].subtract(merged.getBoundingInfo().boundingBox.vectorsWorld[1])).normalize();
if(normalfacebounding.z <0){box.rotation.y= BABYLON.Vector3.GetAngleBetweenVectors(normalfacebounding,new BABYLON.Vector3(1,0,0),BABYLON.Vector3.Cross(normalfacebounding, new BABYLON.Vector3(1,0,0)).normalize());}
else{box.rotation.y= -BABYLON.Vector3.GetAngleBetweenVectors(normalfacebounding,new BABYLON.Vector3(1,0,0),BABYLON.Vector3.Cross(normalfacebounding, new BABYLON.Vector3(1,0,0)).normalize());}

However, sometimes, when I drag the rotation gizmo fast, the box mesh gets out of the bounding box. Do you know why?

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