Forums Solaris and Karma Rotating USD UVs with VEX/VOP ?

Rotating USD UVs with VEX/VOP ?

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OllieS7
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Joined: Aug. 2019
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Hi there.

I wish to edit (rotate) UVs on a specific prim within a USD layer reference in Solaris. I tried the TransformUV LOP, however the rotation seems to be only available in object space - I really want to be able to rotate in the UV/map space. Is there a way to achieve this?

Additionally, adding a TransformUV after the Reference node stops all prims from making it to my next node (CopyToPoints) - what's the right way to address this?

Alternatively, can anyone point me to a VEX example for modifying USD data (such as ST attributes) inline?

Thanks!
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jens_martensson
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Joined: March 2020
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Hi
The idea here is to move uv's to origin, so its assuming no UDIM's
But this will rotate the uv's by 90 degrees 

// move original uv's (st) to origin
vector2 uv = u@primvars:st - 0.5;
matrix UV = ident();

//rotate 90 degrees
rotate(UV,radians(90),{0,0,1});

//rotate the uvs with matrix multi 
uv *= matrix2(UV);

//assign to uv's again
u@primvars:st = uv + 0.5;

Hope that helps
Cheers
Edited by jens_martensson - March 1, 2020 17:58:28
Jens Martensson
Effects Supervisor @ Weta FX
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