Retime slow motion points

[Omegaroth]

Hello all, I have a sand set up based on points being advected by vdb vel. The results come out nice enough but the motion is too fast. I need the speed sim/solver speed to remain the same though to retain the kind of details I'm getting so I can't just multiply the fps down in the solver to cheap a slow-mo effect.

What I'm looking for is to simply retime the points post-cache and make my cache slow-mo, which actually works using a timewarp (I just stretched the output range an extra few hundred frames) -- The slo mo effect is achieved but there is obvious stepping in between frames where the cache will freeze and play ever other frame (due to the stretching)

To avoid this kind of stepping I tried using a timeblendql, which seems to have almost worked but because my points are dying and being deleted based on age, the timewarp breaks. Timewarpql has a neat feature where you can use the v of the point to blend between subframes, but since I'm inheriting my point v from the vdb vel its not as accurate is if you were using a trail sop, and again the trail sop breaks in my scenario because of the points being deleted perhaps based on age..

I can smooth the points together in post with nuke using a frameblend and you don't see the stepping... But i'm sure there is a proper and procedural way to interpolate between the substep frames of the point between A + B... just not sure how to go about this and I am having trouble finding a reference on the net. It would also be nice to have this setup on hands in the future.

 

Thanks for all your time!

[violalyu]

using match by id probably?

[Omegaroth]

i had to create the id's within the solver, feelsdumbman