Velocity volume blending has always had a glaring omission in my opinion. Add mode gets out of hand, Blended Average values are hard to nail down, what I want is to pick the greater velocity from the existing vel and my new source vel. I’m sure most users think that’s what Maximum mode is, but it is not! In fact it picks the larger numeric value for each component – so if you have a volume of {0,0,0} and you try to blend in some {-2,0,-2}, you still end up with a volume of all zeros. This is easy to confirm with the attached scene by bypassing the added switch node.
The attached scene has an additional Field VOP that overrides the default Maximum behaviour with what I think is the more logical operation – the longer velocity vector is picked for each voxel.
daily.hip 
Very nice, Eetu! This Maximum behavior has been driving me crazy lately. Do you have an idea of how your fix could be implemented when using a Gas Particle to Field as a source?
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Not too pretty but an easy way should be to direct your Gas Particle to Field to write to e.g. “tempvel2” field (you need to create it too), and then change the Bind node I added to use tempvel2 instead of tempvel in the above scene.
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Reblogged this on hick3d.
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