Size of imported model with rotation

Questions
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1

I am importing a model from Blender. I calculate its size and create a cube with the same size. Everything works, but if you initially rotate the model in blender and then import it into the project, for some reason the cube size becomes larger than the model.

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{D618F108-FD32-42C5-9FDF-CB7F432ACB21}322×303 2.75 KB

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2

Box3 calculates the size of a model based on its transformations, including scaling and rotation. For example, if you rotate a cube using cube.rotation.set(Math.PI / 2, Math.PI / 4, 0) or scale it with cube.scale.y = 2, its height will increase.

As a quick fix, you can temporarily reset the model’s rotation, compute the size, and then restore the original transformations.

// 1. Save the original rotation
const originalRotation = mesh.rotation.clone();

// 2. Set default rotation
mesh.rotation.set(0, 0, 0);

// 3. getSize
const size = new Vector3();
box3.setFromObject(cube).getSize(size);

// 4. Restore the original rotation
mesh.rotation.copy(originalRotation);
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