Exported alembic missing motionblur on some frames.

[ekan de]

So, i made a fluid sim with vellum that interacts with a rbd sim of a shattering wineglass. all good in that sim and it worked kinda expected.

Then i wanted to test to do the same "shot" but with flip fluids and instead of using breakeable rbd i made it with materialfracture.

 

The problem comes when exporting everything to maya and rendering it. Im rendering with vray for maya cause i havent got to learning karma in houdini yet and focusing on getting small projects out instead of just fiddling.

On some frames the motionblur is missing on the glass.

The fluid works correctly and renders fine. 

Comparing the motionvectors on the points it looks correct on all frames.

 

Here is a link to the first setup i did with vellum and rbd make breakeable.

And at the bottom is a image of how it looks with materialfracture used for the glass.

I have tried all setting i can come up with in houdini when exporting to alembic. Tried motionblur (on/off), different formats, promoting the v attribute from points to vertex and renaming it to velocity, vel v and so on. There is only on some frames the motionblur is missing wich is the strange thing.  If i check the geometry spreadsheat all the pieces have v attributes that are changing on every frame so the motionblur should be there. I understand that it can be the changing point count but how do i solve this? 

 

Oh and if i import the alembic via the vray proxy the motionblur works on all frames but instead i get weird artifacts with extra edges inside the glass pieces.

 

Thanks!

 

 

 

[Sepu]

I would highly recommend using the Alembic from Bifrost instead, then save an alembic from there and load it as vray proxy or just convert the alembic to Maya geo. It should fix the issue. 

[ekan de]

@Sepu Not sure exactly what you mean. I should write the alembic from houdini do disk, take it into maya, and then export it with bifrost from maya and read it in again?

[Sepu]

Take the .abc from Houdini and read it back in the Bifrost graph, you can create a Maya mesh directly there. Post a file if you need more help.