Brep transformation doesn't seem to have any effect

[chenkasirer]

I'm trying to transform a Brep represented by a TopoDS_Solid but either the transformation doesn't work (or I'm doing it wrong) or I'm looking at the wrong properties.

As a minimal example, I'm using a simple box brep from this zipped STEP file, and a simple translation matrix.

> occ_brep
<class 'TopoDS_Solid'>

The transformation matrix

t = gp_Trsf()
t.SetValues(
    1., 0., 0., 4.,
    0., 1., 0., 3.,
    0., 0., 1., 0.,
)

I'm expecting to see the effect in occ_brep.Location().Transformation(). Prior to the transformation, the values of Transformation() are as follows:

> l = occ_brep.Location().Transformation()
> print(f"{l.Value(1,1)} - {l.Value(1,2)} - {l.Value(1,3)}")
> print(f"{l.Value(2, 1)} - {l.Value(2, 2)} - {l.Value(2, 3)}")
> print(f"{l.Value(3, 1)} - {l.Value(3, 2)} - {l.Value(3, 3)}\n")
1.0 - 0.0 - 0.0
0.0 - 1.0 - 0.0
0.0 - 0.0 - 1.0

As per the examples I could find, I am using BRepBuilderAPI_Transform to apply the transformation:

builder = BRepBuilderAPI_Transform(occ_brep, t, False)

Printing occ_brep.Location().Transformation() after that shows the values have not changed.

> l = occ_brep.Location().Transformation()
> print(f"{l.Value(1,1)} - {l.Value(1,2)} - {l.Value(1,3)}")
> print(f"{l.Value(2, 1)} - {l.Value(2, 2)} - {l.Value(2, 3)}")
> print(f"{l.Value(3, 1)} - {l.Value(3, 2)} - {l.Value(3, 3)}\n")
1.0 - 0.0 - 0.0
0.0 - 1.0 - 0.0
0.0 - 0.0 - 1.0

I've tried the following variation as well:

builder = BRepBuilderAPI_Transform(occ_brep, t, False)
builder.Perform(occ_brep)

builder.Shape().Location().Transformation as well as builder.ModifiedShape().Location().Transformation are also unchanged.

Using occ_brep.Move(TopLoc_Location(t)) directly also made no difference.

Would appreciate any help understanding what I'm doing wrong. Thanks!