Help How to stack different colors but keep their volumes

[wm4583816]

Q1 -Fluid compressibility depends on what your simulation budget is. If you spend few iterations and have a large-ish timestep, fluid will be more compressible. In other engines, it would outright explode or become inestable. Obi degrades much more gracefully though, as it is unconditionally stable.

Try increasing the amount of density constraint iterations, and/or the amount of substeps. To see how iterations/substeps affect the simulation, see:
http://obi.virtualmethodstudio.com/tutor...gence.html

A trick that many games use to avoid having to crank up simulation quality, is to simply reduce gravity a bit. This reduces the fluid pressure, and allows density constraints to be more effective.

Q2 - More particles->less performance. If you want a clearer interface between the two fluids, you can try reducing "smoothing" in the fluid renderer.

Thanks for your reply. The Q1 is mostly solved. But the Q2 still exists. I upload a pic that shows the interface between the two fluids. There is a serious graininess at the interface.