Aug 2010
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Aug 2010
Aug 2010
mitchbraggart
Aug '10

Hi everybody!

I am trying to get a motionvector pass from a fluid.
i've red that if i convert The fluid into polygons i can output a motion vector Pass for the Fluid.
My fluid (the polygonal version) is on a seperate layer. Applied to this layer is a 2D motionvector Pass.

I render out a 3x32 bit Normal Float openEXR.

But if i look at the openEXR i only get a image with a suttle gradient from left to right in the red channel of the motionvector Channel Layer.

However this method is working for the Depth Pass

What am i doing wron here?

Can anybody help?

mitchbraggart
Aug '10

Master Layer!

Sorry for multible post! did not know how to add more screenshots!

mitchbraggart
Aug '10

No one? really?

if you need more information just tell me! i would be happy to give more details!

joojaa
Aug '10

Well see the problem is that your mesh isnt really moving. It gets recreated each frame, thats not movement because thw points dont have correspondence in the new mesh. They dont deform so theres no motion vector to compute.

Quite technically speaking, its possible to get and inetrpolate the vector form the current voxel but havent tried that and it certainly isnt entirely trivial to do.