WEEK 5
updated 2/5/2025
Simulation Tests
Sim_v08 using APIC Velocity Transfer mode
Sim_v10 using FLIP Velocity Transfer mode
Reference
reference
The general shape of the water is fine; I like how the water can be seen from the reflection of the watch. But there is a lot of work to do next:
Make it slow motion.
Camera angle. Now the FX water is not quite visible.
Table reflection.
R&D
Crown_Splash_Particle_Fluid
The shelf tool looks nice, but when I tried to add an Ocean Spectrum on the wavetank to create an ocean surface effect, it was broken.
Crown_Splash_Particle_Fluid with Ocean Spectrum
The reason is that the shelf tool customizes the gravity. However, even though I have made the gravity values equal in both places, the effect is still not ideal.
Shelf tool Gravity
Gravity of both set to -0.098
Velocity Transfer
In FLIP solver, there are two ways of Velocity Transfer, FLIP and APIC.
FLIP (Splashy)
In FLIP mode, it only updates particles using the velocity change (ΔV) from the grid.
Characteristics:
Preserves fine details of fluid motion and reduces numerical dissipation.
It can introduce numerical instability, leading to excessive noise or jittering.
Best for:
Fast-moving, turbulent fluids (e.g., waterfalls, splashes).
Simulations requiring highly detailed motion.
APIC (Swirly)
In APIC mode, the particle velocity is completely replaced by the velocity from the grid.
Characteristics:
Very stable and reduces noise in the simulation.
Causes numerical viscosity, making the fluid appear thicker and less detailed.
Best for:
High-viscosity fluids (e.g., mud, tar).
Situations where excessive particle jittering needs to be avoided.
In current settings, FLIP is way too noisy, and APIC is way too smooth, so a way to mix them is needed.
Substeps
with substeps of 5
with substeps of 1
Dop level Substeps are also a significant factor in simulations when it comes to slow motion.