Overview
Vorticity Confinement measures local curl and applies a force that restores visually important rotational detail.
SpecializedSource checked
Vorticity Confinement
Adds small swirling forces back into fluid simulations to counter numerical damping.
Quick Facts
Compact metadata for implementation and discovery.
- Category
- Simulation
- Difficulty
- Advanced
- Family
- Fluid Detail Enhancement
- Tier
- Specialized
- Status
- Verified
- Review
- Source Checked
- Sources
- 2
- Formulas
- 1
- Relationships
- 3
- Code example
- Ready
- Visualization
- Ready
Core Concepts
curlvorticity magnitudeconfinement forcefluid detail
Quick facts
Complexity
Runtime and memory behavior at a glance.
Best
O(cells)
Average
O(cells)
Worst
O(cells)
Space
O(cells)
When to Use
- Use when fluid motion looks overly smooth because numerical dissipation removed swirls.
- Use when smoke detail enhancement is a central requirement.
When Not to Use
- Avoid when physically measured turbulence is required.
- Avoid when the timestep, constraints, or stability requirements exceed what the method can handle.
What It Does
- Computes fluid detail enhancement within Fluid Detail Enhancement workloads (O(cells) time, O(cells) space).
- Works by Adds small swirling forces back into fluid simulations to counter numerical damping.
- Maintains key invariants across curl, vorticity magnitude, confinement force.
Use Cases
- Smoke detail enhancement
- Game fluid effects
- Visual turbulence control
Inputs
- Velocity field
- Vorticity strength
Outputs
- Adjusted velocity field
Key Formulas (1)
Confinement force
force = ε · normalize(∇(|curl|)) x curl
force = epsilon * normalize(gradient(|curl|)) x curlAdds force near vorticity gradients to restore swirling detail.
Pseudocode
- 1.Compute curl at each grid cell
- 2.Compute gradient of curl magnitude
- 3.Normalize the gradient direction
- 4.Apply a force perpendicular to the gradient and curl
- 5.Add the force to velocity
Canonical Example
- Input
- smoke plume has weak curl
- Output
- added force creates visible rolling detail
- Explanation
- The correction amplifies local rotational features.
Implementation Notes
- Expose the confinement strength as an artist- or simulation-tunable parameter.
- Keep units, timestep size, and state variables explicit in tests.
- Keep a tiny example with expected output beside the implementation.
Common Pitfalls
- Too much confinement creates artificial boiling motion.
- Large timesteps can add energy, damp motion, or make constraints explode.
- Not defining boundary, empty, or degenerate inputs before implementation.
Interactive Mechanism Walkthrough
Iterative Convergence & State TrajectoryShow damped smoke gaining small rolling vortices after confinement forces are applied.
Step 1 of 5: Compute curl at each grid cell
simulation-stateNotes
This is a visual correction, not a substitute for a high-resolution physical solve.
Sources (2)
What each reference supports for this entry.
Visual Simulation of Smoke
PaperReference for vorticity confinement and stable smoke simulation techniques.
Open sourceFluid Simulation for Computer Graphics
BookFluid-simulation reference supporting Vorticity Confinement advection, incompressibility, particle-grid transfer, or numerical fluid update behavior.
Open sourceExplore Next
Good next jumps from the relationship graph, ranked for useful discovery.
Relationships
View full relationship pageOften paired withNavier-Stokes Projection
Vorticity confinement adds small-scale rotational detail to projected fluids.
Conceptual neighborSmoothed Particle Hydrodynamics
Both are used to improve perceived fluid motion detail.
Related Algorithms
Tags
SimulationFluid SimulationPhysicsMesh Method