Extents.transformBy()

[gswifort]

Shouldn't Extents.transformBy(matrix) transform the object the same way as matrix * ext.minPoint; matrix * ext.maxPoint()? Current behavior below - Y don't match.

from pyrx import Db, Ge, command


@command
def doit():
    m_translation = Ge.Matrix3d.translation(Ge.Vector3d(5.0, 5.0, 0.0))
    m_scaling = Ge.Matrix3d.alignCoordSys(
        Ge.Point3d.kOrigin,
        Ge.Vector3d.kXAxis,
        Ge.Vector3d.kYAxis,
        Ge.Vector3d.kZAxis,
        Ge.Point3d.kOrigin,
        Ge.Vector3d.kXAxis * -1.0,
        Ge.Vector3d.kYAxis * 1.0,
        Ge.Vector3d.kZAxis * 1.0,
    )
    m_rotation = Ge.Matrix3d.rotation(45.0, Ge.Vector3d.kZAxis, Ge.Point3d.kOrigin)
    m = m_translation * m_rotation * m_scaling

    ext = Db.Extents(Ge.Point3d(-1.0, -1.0, 0.0), Ge.Point3d(1.0, 1.0, 0.0))
    print(f"{ext=}")
    print(f"{m*ext.minPoint()=}")
    print(f"{m*ext.maxPoint()=}")
    print(">> ext.transformBy(m)")
    ext.transformBy(m)
    print(f"{ext.minPoint()=}")
    print(f"{ext.maxPoint()=}")

# output:
ext=PyGe.Extents((-1.00000000000000,-1.00000000000000,0.00000000000000),(1.00000000000000,1.00000000000000,0.00000000000000))
m*ext.minPoint()=PyGe.Point3d(6.37622551335185,5.32558153571639,0.00000000000000)
m*ext.maxPoint()=PyGe.Point3d(3.62377448664815,4.67441846428361,0.00000000000000)
>> ext.transformBy(m)
ext.minPoint()=PyGe.Point3d(3.62377448664815,3.62377448664815,0.00000000000000)
ext.maxPoint()=PyGe.Point3d(6.37622551335185,6.37622551335185,0.00000000000000)

[CEXT-Dan]

according to the docs, the extents is recomputed to include the transformed points. Extents is always WCS aligned, to transformby will only grow or shrink the cube

[gswifort]

ok, I think I understand my mistake - I probably did it in the wrong order - I should transform the object and then calculate its Extents instead of transforming the Extents.

[CEXT-Dan]

you probably already know this, but use caution scaling block references non uniformly, it can add funny behavior when exploding or in data extraction.