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Zabander

Exporting Alembic from Houdini to Maya - No motion blur

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Hey guys!, have an issue exporting liquid mesh from from Houdini to Maya, when I import it using alembic. When I turn motion blur it just doesn't work, any ideas??

 

thanks!

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Yes. It is standard alembic problem.

 

Alembic exporter recognizes fixed topology and optimize file size based on it. If topology is constant over time it could be resampled in any fractional time in the middle of any two succesive frames simple by blending position vector from previous frame to next one. And that approach  is used for motion blur.calc.

 

Exporting fluid meshes and similar "topology changing over time" primitives require velocity attribute on points for proper calculation of motion blur since there is no way to match point position from one frame to another.

 

In alembic exporter node turn on export attributes. Before that check that geometry you are exporting really has velocity attribute

 

cheers

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yeah, changing topology requires velocities for each point to do blur.... but does the renderer you're using support velocity vector motion blur?

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Im curently using vray, in Maya. I turned on the export velocity in the rop_alembic node but it doesn't arrive to Maya, inside Houdini works fine when I reimport the alembic back but in maya doesn't work. Apparently is an issue with Maya. I have to convert to vramesh to render.

Edited by Zabander

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you can use Vray Proxy and load alembic directly through it at render time, it will have correct motion blur if you have v attribute

however we experienced sudden UV loss on some frames if the geometry has changed topology

to address that you may need to export abc per frme and then load as Vray Proxy using <frame> token

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