# Density & Upscaling Sim Math

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I'm quite new in Houdini, and am spending time just getting to grips with a liquid pour in a glass. To make things a bit more challenging, I've included some ice into the sim, allowing me to experiment with how FLIP interacts with RBD solvers.

From an artists perspective, the two things are most important to me in terms of this particular sim: the scale of the liquid and the behavior of the ice, as the ice needs to float right near the surface, but not above it.

In a perfect world (the one I'm trying to attain) - I could use many low-res simulations to test the correct densities of the water and the ice, and also to tweak my spacial scale & feedback scale to get the correct liquid & ice movement.

However, once I decrease my particle separation to upres my sim, I also have to tweak my particle radius scale - and since these settings directly modify the densities of the liquid, I then have to redial in all my object densities, spacial scale, and feedback scale in order to get the visuals I want - and it takes quite a bit of time to iterate through all these tweaks with a high res sim.

So I was wondering - is there some sort of direct math correlation between all of these parameters?

For instance, in the camera world there is a direct relationship between your F-stop & your shutterspeed in terms of the amount of light being let into the camera. If you have to adjust your shutter speed, but don't want to change the amount of light being let in, you can quickly consult the chart to figure out exactly how much to tweak your f-stop in order to compensate; the same being true in reverse - If you need to adjust your exposure, you can consult the chart & know exactly how much to change your shutter speed.

Is there something similar for FLIP sims that shows the relationship between the different parameters - so that if I need to adjust parameter X, I'll know exactly how much I need to adjust parameters Y & Z?

Thanks,

Luke

Edited by LukeLetellier

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