Generating motion vectors from existing flipbook?

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Gang,

There are a variety of options to do this outside Houdini, but I was wondering if there was an easy way to use an existing flipbook (such as an 8x8 animation of smoke) as input into Houdini and be able to generate motion vectors. The idea would then be to use those motion vectors along with the flipbook to get smoother playback in the game engine.

I know I can use tools such as Slate or Nuke to crank out these motion vectors, but I'm hoping I can use Houdini.

Thanks for any pointers!
–GY
gregory yepes | http://www.GregoryYepes.com [www.gregoryyepes.com]
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Hey Gregory,

Unfortunately, there isn't an easy way to do this in Houdini. I've got a test file lying around somewhere but it would need some cleanup. The basic idea is to bring your 8x8 texture into cops and then isolate each frame with a crop and some expressions.
Then bring that texture into SOP's using a copnet set to volume slice. Then you can use the volume optical flow with a time shift for the next frame to generate a motion vector. Then that goes back into cops to render out the texture.

Like some other 2D optical flow motion vector methods you have to fiddle with the parameters to get something that works nicely.

So there's a way. But it's not easy.

Mike
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Thanks for the response Mike! I was just watching Mark's video describing some of this process:

https://vimeo.com/242373845 [vimeo.com]

Definitely cool, but it's a deeper rabbit hole than I'd like to dive into at the moment… I'll explore other options and come back to this when I have more time.

cheers!
–GY
gregory yepes | http://www.GregoryYepes.com [www.gregoryyepes.com]
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