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Quaternion Vex/Python equivalents

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julien-b
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Joined: 3月 2017
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Hi guys,

I'm struggling to find the equivalent functions in python and vex when it comes to quaternions.

This seems to be working in Python :
o1 = hou.Quaternion()
o1.setToVectors(hou.Vector3(0, 1, 0), self.normal)
o2 = hou.Quaternion()
q = o2.slerp(o1, ratio)
How would I get the same result in Vex?
Or if even my Python code is wrong, how can I get the same result in Vex/Python for what I'm trying to achieve ?

Thanks a lot,

Julien
Edited by julien-b - 2020年5月18日 18:13:50
VFX Supervisor @ MPC London
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julien-b
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Joined: 3月 2017
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Ok, I think I found the answer : dihedral seems to be the vex equivalent of Quaternion.setToVectors() !

Cheers,

Julien
VFX Supervisor @ MPC London
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animatrix_
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Joined: 2月 2012
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Hey Julien

It's even more confusing in VOPs if you try to search dihedral, it's called Align VOP

At least in the HDK, it's also called dihedral:
https://www.sidefx.com/docs/hdk/class_u_t___matrix3_t.html#a4326291ec8a372e8315fdba3eef42588 [www.sidefx.com]

I think numpy doesn't have a function for this but in scipy it's available:
https://docs.scipy.org/doc/scipy/reference/generated/scipy.spatial.transform.Rotation.align_vectors.html [docs.scipy.org]
Senior FX TD @ Industrial Light & Magic
Get to the NEXT level in Houdini & VEX with Pragmatic VEX! [www.pragmatic-vfx.com] https://lnk.bio/animatrix [lnk.bio]
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