Reaction Diffusion
Grow source-aware chemical patterns such as spots, stripes, labyrinths, coral, and mitosis cells.
Add Reaction Diffusion
Open an image or build the source composition first. Put this effect after the content it should process in stack processing order. Choose Material → Organic → Reaction Diffusion in the effects picker, or search for Reaction Diffusion with Cmd/Ctrl + F. Select the new layer in Layers to open its Effect Panel.
Choose a growth model
Choose Model and a starting pattern, then set Source and Influence for the relationship to the incoming image. Adjust Growth Time to see the pattern develop.
Tune the chemistry
Change Growth Supply, Pattern Decay and the spread controls in small increments. Seed placement and edge behaviour change where growth forms.
Finish the material
Choose Palette or Tint, then use the lighting controls for relief. In Video or Live, animate supported growth controls and play forward to inspect the change.
Edit the shared palette
Set Output to False Colour to show Palette. Colors and Palettes explains adding and moving stops, editing colour and opacity, extracting colours and saving a palette for reuse.
Set an individual colour
Click the relevant colour swatch to open its picker. Colors and Palettes explains colour values, transparency and the canvas sampling controls where available.
Compare and finish
Toggle the layer eye to compare with the incoming composition. Use the Effect Panel footer for opacity and blend mode, or add a mask to limit the affected area. In Video or Live, use the function menu on a supported control to add keyframes or a driver.
Control reference
Show individual controls
| Control | What it does | Values and animation |
|---|---|---|
| Edge Behavior | Edge Behavior: what the chemistry sees past the canvas edge | Hold Edge / Wrap Around / Mirror Edge Default: Hold Edge Discrete keyframes |
| Center Seed | plant a small V blob at a chosen point | On / Off Default: Off Not keyframeable |
| Center Seed Radius | Size: radius of the authored seed disk | 0.005 to 0.1 Default: 0.02 Continuous keyframes |
| Center Seed X | Horizontal position of the additional reaction seed blob, as a fraction of the simulation width. | 0 to 1 Default: 0.5 Continuous keyframes |
| Center Seed Y | Vertical position of the additional reaction seed blob, as a fraction of the simulation height. | 0 to 1 Default: 0.5 Continuous keyframes |
| Palette | false-colour palette for the output | Available presets Default: viridis Discrete keyframes |
| Tint | tint painted over the source where V is high | Colour Default: #E8E5DE Colour keyframes |
| Pattern Amount | how strongly the composite colour replaces the source | 0% to 100% Default: 55% Continuous keyframes |
| Background Spread | Background Spread: how quickly the background field smooths outward | 0.1 to 2 Default: 1 Continuous keyframes |
| Pattern Spread | Pattern Spread: how quickly the visible activator spreads before forming dots and bands | 0.05 to 1 Default: 0.5 Continuous keyframes |
| Step Size | Step Size: how far each solver step jumps; higher is faster but less stable | 0.5 to 2 Default: 1 Continuous keyframes |
| Growth Supply | Growth Supply (F): adds fresh background chemical; paired with Pattern Decay to pick the look | 0 to 0.1 Default: 0.029 Continuous keyframes |
| Guide Angle | Guide Angle: direction for set-angle growth | 0° to 360° Default: 0° Continuous keyframes |
| Direction | Direction: optional guide that bends growth across the canvas | Off / Follow Image / Set Angle Default: Off Discrete keyframes |
| Guide Strength | Guide Strength: how strongly diffusion follows the direction guide | 0% to 100% Default: 0% Continuous keyframes |
| Recovery Offset | Recovery Offset: shifts the recovery field's resting state | 0 to 1.5 Default: 0.7 Continuous keyframes |
| Recovery Pull | Recovery Pull: how strongly the pulse pulls back to rest after firing | 0 to 1.5 Default: 0.8 Continuous keyframes |
| Baseline Excitation | Baseline Excitation: constant firing pressure across the canvas | -1 to 1 Default: 0 Continuous keyframes |
| Recovery Speed | Recovery Speed: lower values recover slowly and make denser spirals | 0.001 to 0.5 Default: 0.08 Continuous keyframes |
| Invert Colormap | Reverses the direction in which the reaction-diffusion field maps into the selected colour palette. | On / Off Default: Off Not keyframeable |
| Invert | flip light and dark in the output | On / Off Default: Off Discrete keyframes |
| Growth Time | How far the reaction has grown. Animate upward to keep it evolving; looping playback restarts growth | 1 to 99999 Default: 5000 Discrete keyframes |
| Pattern Decay | Pattern Decay (k): removes activator chemical; paired with Growth Supply to pick the look | 0.04 to 0.075 Default: 0.057 Continuous keyframes |
| Light | azimuth of the Relief light | 0° to 360° Default: 135° Continuous keyframes |
| Elevation | height of the Relief light | 0° to 90° Default: 45° Continuous keyframes |
| Intensity | strength of Relief shading | 0 to 2 Default: 1 Continuous keyframes |
| Model | Gray-Scott for spots and labyrinths, FitzHugh-Nagumo for spirals | Gray-Scott / FitzHugh-Nagumo Default: Gray-Scott Discrete keyframes |
| Steer | Steer: which simulation value the source image pushes each step | Off / Growth Supply / Pattern Decay / Background Spread / Pattern Spread / Supply + Decay / Pattern Map Default: Off Discrete keyframes |
| Source | Source: which channel of the source drives image influence | Luminance / Red / Green / Blue Default: Luminance Discrete keyframes |
| Influence | Influence: how hard the image pulls the chosen value | 0% to 100% Default: 30% Continuous keyframes |
| Contrast | boost weak patterns or soften hard edges | 0 to 2 Default: 1 Continuous keyframes |
| Gamma | above 1 brightens the pattern, below 1 darkens | 0.1 to 3 Default: 2 Continuous keyframes |
| Output | how the chemistry is converted into pixels | Tinted Source / Pattern (B&W) / Pattern Inverse / U/V Channels / False Colour / Edges / Displace / Relief / Source Mask (alpha) Default: Pattern (B&W) Discrete keyframes |
| Dark Pattern | pattern recipe used for dark source regions | Spots / Stripes / Labyrinth / Coral / Mitosis / Solitons / Chaos Default: Spots Discrete keyframes |
| Bright Pattern | pattern recipe used for bright source regions | Spots / Stripes / Labyrinth / Coral / Mitosis / Solitons / Chaos Default: Labyrinth Discrete keyframes |
| Preset | pre-built recipe; Custom lets you dial it in yourself | Available presets Default: labyrinth Discrete keyframes |
| Ambient | minimum light kept in Relief shadows | 0% to 100% Default: 32% Continuous keyframes |
| Height | height scale of the simulated chemistry field | 0 to 4 Default: 1 Continuous keyframes |
| Height Field | which chemical field becomes the Relief height map | V Field / U Field Default: V Field Discrete keyframes |
| Channel | which colour channel is used as V | Red / Green / Blue Default: Red Discrete keyframes |
| Start From | Start From: how the initial activator islands are placed | Brightness / Edges (Sobel) / Threshold / Image Channel / Random / Uniform (Generative) Default: Uniform (Generative) Discrete keyframes |
| Noise | small random sprinkle that breaks symmetry | 0% to 100% Default: 2% Continuous keyframes |
| Seed Points | authored seed disks on the canvas | Editable reaction seeds Default: 16 entries Per-seed keyframes |
| Seed | change for a different random pattern | 0 to 9999 Default: 0 Continuous keyframes |
| Threshold | brightness cutoff that splits the image into U and V | 0% to 100% Default: 50% Continuous keyframes |
| Pattern Detail | Pattern Detail: internal simulation cap; higher is sharper but slower | Low (512) / Medium (768) / High (1280) / Max (2048) / Full (no cap) Default: Medium (768) Discrete keyframes |
| Stops | Editable palette stops used to colour the reaction-diffusion simulation. | Gradient stops Default: None Not keyframeable |
| Use Gpu | run the simulation on the GPU when available | On / Off Default: On Not keyframeable |