Bug on rotation attribute?

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1

Hello,

I have attached two usd files with the same rotation applied to a prim.
The testSeparateRot.usd expresses the rotation in the form of:

float xformOp:rotateX = 90
float xformOp:rotateY = 90
float xformOp:rotateZ = 45
uniform token[] xformOpOrder = ["xformOp:rotateX", "xformOp:rotateY", "xformOp:rotateZ"]

While the testGroupRot.usd has the rotation in the form of:

float3 xformOp:rotateXYZ = (90, 90, 45)
uniform token[] xformOpOrder = ["xformOp:rotateXYZ"]

The two files have the same rotation order and values to each component, so I expected them to be displayed the same, but as we can see on the image below, opening them in usdview they are rendered differently from each other

image
image2844Ɨ1245 366 KB

If I swap the x and z in the rotation order of the one that is split they get the same orientation:

uniform token[] xformOpOrder = ["xformOp:rotateZ", "xformOp:rotateY", "xformOp:rotateX"]

Am I wrong to assume that the rotation order of the combined attribute should be the same for when the rotation is split? Or this a bug?

Ps: Iā€™m using usd 25.05

testSeperateRot.usd (3.0 KB)
testGroupRot.usda (2.8 KB)

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2

I guess I found my answer in the xformable.h

/// If it were important for the prim's rotations to be independently 
/// overridable, we could equivalently (at some performance cost) encode
/// the transformation also like so:
/// \code
/// float xformOp:rotateX = 30
/// float xformOp:rotateY = 60
/// float xformOp:rotateZ = 90
/// float3 xformOp:scale = (2, 2, 2)
/// double3 xformOp:translate = (0, 100, 0)
/// uniform token[] xformOpOrder = [ "xformOp:translate", "xformOp:rotateZ", "xformOp:rotateY", "xformOp:rotateX", "xformOp:scale" ]
/// \endcode
/// 
/// Again, note that although we are encoding an XYZ rotation, the three
/// rotations appear in the **xformOpOrder** in the opposite order, with Z,
/// followed, by Y, followed by X.
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