Pyron — Documentation & Help
A true GPU volumetric fluid simulation for After Effects. Pyron simulates fire and smoke with a real Navier–Stokes solver and physically based blackbody emission — no stock footage, no flat sprites.
After Effects 2021 & laterWindows & macOSGPU · OpenCL / Metal8 / 16 / 32 bpc
Overview
Pyron generates fire, smoke and burning effects entirely on the GPU. Instead of compositing pre-rendered elements, it runs a 3D fluid simulation every frame: heat rises, fuel burns, smoke trails, and the volume is ray-marched with temperature-driven blackbody color. The result reacts to your parameters, your source layer, your comp lights and your camera in real After Effects 3D space.
Key features
- Volumetric Navier–Stokes solver — buoyancy, vorticity, turbulence, combustion and pressure projection.
- Three emission modes — point/sphere emitter, a source layer (burn your logo or text), and a motion path.
- Physically based color — blackbody (Kelvin) or a fully custom gradient.
- Burn modes — directional, radial, dissolve and iris reveals driven by Burn Progress.
- Integrated lighting — self-shadowing, fire self-illumination and comp Key Light support.
- 16 presets, multiple parameter tabs, full 8/16/32-bit (float) pipeline.
Installation
Pyron is a single plug-in file — you copy it into an After Effects plug-ins folder and restart AE. A step-by-step How to Install guide (with copyable paths) is included in your download.
Windows — Shared location (all AE versions):
C:\Program Files\Adobe\Common\Plug-ins\7.0\MediaCore\
Windows — Specific AE version:
C:\Program Files\Adobe\Adobe After Effects [version]\Support Files\Plug-ins\
macOS — Shared location (all AE versions):
/Library/Application Support/Adobe/Common/Plug-ins/7.0/MediaCore/
macOS — Specific AE version:
/Applications/Adobe After Effects [version]/Plug-ins/
- Extract the downloaded archive.
- Copy
Pyron.aex(Windows) orPyron.plugin(macOS) to one of the paths above. - Restart After Effects.
Tip: if Windows marks the file as blocked, right-click
Pyron.aex →
Properties, tick Unblock (if shown), click OK, then copy it again.
After installation, the plugin appears under Effect > YCraft > Pyron in the Effects & Presets panel.
macOS: run the included Pyron_Setup installer (.pkg) — it places the plug-in automatically. Then restart After Effects.
Registration
When you buy Pyron on ycraft.dev, your license key is shown on screen right after checkout and also emailed to you. One license activates Pyron on up to 2 machines.
Pyron runs in trial mode until a valid license is entered. In trial mode, a watermark overlay is applied to the rendered output. To activate:
- Apply Pyron to a layer in After Effects.
- In the Effect Controls panel, click Options (top-right of the effect header).
- Paste your license key and click Activate.
- The watermark disappears after successful activation.
Activation needs an internet connection once; after that the license is verified offline,
so Pyron keeps working without a connection.
Note: The watermark disappears immediately after successful activation —
Pyron automatically invalidates the cache when license state changes.
In rare cases (e.g. complex MFR pipelines), if the watermark persists,
go to
Edit > Purge > All Memory & Disk Cache or change any parameter to force a re-render.
Quick Start
- Create a Solid (or select any layer) and apply Effect ▸ YCraft ▸ Pyron.
- Open the Presets tab and pick a starting look (e.g. Logo Fire, Fire Trail, Burn Dissolve).
- For a logo / text burn: set a layer as the source (Pattern Type ▸ Source Layer) — its alpha seeds the fire.
For a free flame: use the Source Position point in the comp with the sphere emitter. - Tune Life, Buoyancy and Turbulence for the motion, then Color for the look.
- Design at a light Voxel Size; for final render raise it and set Quality ▸ Ultra. See Performance.
Parameter Reference
Click a group to expand it.
Presets
| Parameter | Description |
|---|---|
| Preset | One-click starting looks (16). Custom leaves your settings untouched; the others stamp a complete look — Logo Fire family (source layer), Fire Trail family (source point), and Burn family (Softness, Sharpness, Directional, Radial, Dissolve, Iris). |
Emitter & Source
How and where fuel enters the simulation. Pattern Type / Mask / Path Emitter / Light Source form the Source Pattern sub-group.
| Parameter | Description |
|---|---|
| Pattern Type | Emission source: sphere emitter, a source layer's alpha, or a custom map. |
| Mask Scale | Scales the source pattern/alpha used to seed emission. |
| Mask Contrast | Increases contrast of the source alpha so edges read sharper. |
| Mask Threshold | Cutoff below which source alpha does not emit. |
| Path Emitter | Emit along a motion path (e.g. a trailing flame following the Source Position). |
| Light Source | Optionally drive emission position from a comp light (Off / Auto / Light 1–4). |
| Emitter Radius | Size of the spherical emitter (point-source mode). |
| Source Size X / Y / Z | Per-axis size of the emission region. |
| Source Temperature | Initial heat injected at the source — drives color (blackbody) and buoyancy. |
| Fuel Amount | How much combustible fuel is injected; higher = thicker, longer-burning fire. |
| Life | How long fire/smoke persists before cooling away. |
| Life Softness | Softens the fade of dying smoke for a smoother tail (render-side). |
| Fade | Global fade of the emission over its lifetime. |
| Fade Softness | Softness of the fade transition. |
| Trail | Length of the emitted trail when the source moves over time. |
| Opacity | Final output opacity of the whole effect. |
Source Position is set with the effect's point control directly in the comp.
Fire Physics
| Parameter | Description |
|---|---|
| Burn Threshold | Temperature at which fuel ignites. |
| Burn Rate | How quickly fuel is consumed into heat + smoke. |
| Heat Output | How much heat each burn produces (brighter, more buoyant fire). |
| Smoke Output | How much smoke each burn produces. |
| Heat Decay | How fast heat cools (faster = shorter flames). |
| Smoke Decay | How fast smoke dissipates. |
Physics
| Parameter | Description |
|---|---|
| Buoyancy | Upward force on hot fluid — the main driver of rising flame. |
| Gravity | Downward force (use for falling embers / heavy smoke). |
| Drag | Air resistance; damps motion for a calmer, more viscous look. |
| Wind X / Y / Z | Directional wind force on the volume. |
| Speed | Simulation time scale — speeds up or slows down the whole sim. |
| Random Seed | Varies the turbulence/noise pattern (active when Turbulence > 0). |
Burn
Reveal-style burning driven by Burn Progress (keyframe it to animate the burn).
| Parameter | Description |
|---|---|
| Burn Mode | Reveal style: Softness, Sharpness, Directional, Radial, Dissolve, Iris. |
| Burn Direction | Angle of a directional burn sweep. |
| Burn Progress | 0–100% of the burn reveal. Keyframe this to animate a logo igniting. |
| Burn Width | Width of the active burning edge. |
| Burn Noise | Irregularity of the burn front for a natural, ragged edge. |
| Spark Boost | Extra heat/brightness along the burning edge. |
Turbulence
| Parameter | Description |
|---|---|
| Vorticity | Vorticity confinement — restores small swirls the solver would otherwise smooth away. |
| Turbulence | Amount of divergence-free curl noise added to the motion. |
| Turbulence Scale | Size of the turbulent features (large rolls vs fine wisps). |
| Turbulence Speed | How fast the turbulence field evolves. |
Heat Distortion
Screen-space heat-haze refraction around the fire.
| Parameter | Description |
|---|---|
| Heat Amount | Strength of the heat-haze distortion. |
| Heat Scale | Size of the distortion ripples. |
| Heat Complexity | Detail/octaves of the distortion noise. |
| Heat Evolution | Animation phase of the distortion field. |
| Heat Rise | How much the haze drifts upward with the heat. |
Color ▸ Fire
| Parameter | Description |
|---|---|
| Color Mode | Blackbody (physical, temperature-based) or Custom (your own gradient). |
| Min / Max Color Temp | Blackbody temperature range in Kelvin (maps cool→hot to color). |
| Source | Custom gradient — hottest color (flame core). |
| Mid | Custom gradient — mid color. |
| Gamma | Bias of the color ramp toward hot or cool. |
| Intensity | Overall fire emission brightness. |
| Burn Cutoff Center / Width | Where (and how softly) the visible flame fades to nothing along temperature. |
Color ▸ Smoke
| Parameter | Description |
|---|---|
| Scatter Color | Color of light scattered through the smoke. |
| Smoke Density | Optical thickness of the smoke (absorption). |
| Smoke Brightness | How brightly the smoke is lit. |
| Scatter Anisotropy | Directionality of light scattering (forward vs even). |
Color ▸ Lighting
| Parameter | Description |
|---|---|
| Self Shadow | Smoke casting shadow on itself for volumetric depth. |
| Fire Light | How much the fire illuminates the surrounding smoke. |
| Key Light | Use a comp light as a key (Off / Auto / Light 1–4). |
| Volumetric Depth | Strength of the depth/volume shading. |
| Ambient Color / Strength | Fill light color and intensity on the volume. |
Color ▸ Grading
| Parameter | Description |
|---|---|
| Color Tint | Overall color tint applied to the result. |
| Brightness Flicker | Subtle animated brightness variation (candle/torch feel). |
| Hue Shift | Rotates the hue of the whole render. |
| Saturation | Color saturation. |
| Exposure | Overall exposure (stops). |
Sharpness
Render-side detail controls that sharpen the flame silhouette without re-simulating.
| Parameter | Description |
|---|---|
| Density Contrast | Contrast curve on density — crisper flame edges. |
| Opacity Threshold | Cuts the faintest haze for a cleaner edge. |
| Edge Sampling | Volume sampling: Smooth (B-spline), Sharp (Catmull-Rom) or Ultra Sharp. |
| Flame Aggression | Master boost to vorticity/buoyancy for more aggressive, licking flames (sim-side). |
| FBM Flow | Flow-advected detail noise for finer, animated structure. |
| Inner Wisps | Adds fine internal filaments inside the flame. |
Render
| Parameter | Description |
|---|---|
| Quality | Render quality (anti-aliasing & ray-march sampling): Draft / Normal / High / Ultra. Affects how the volume is drawn, not how it is simulated. |
| Voxel Size | Simulation grid resolution — the main driver of sim speed and detail. Lighter = faster (use while designing); finer = more detail (use for final render). |
| Detail Noise | Render-side fractal detail added to the volume. |
| Detail Scale | Size of the detail-noise features. |
| Detail Octaves | Number of noise octaves (more = finer, slightly slower). |
| Bloom | Glow around bright fire. |
| Light Cast | Extends the fire's glow/light into the surrounding area. |
| Motion Blur | Off / Effect Only / Comp Settings — velocity-based motion blur. |
| Shutter Angle | Motion-blur shutter (when Motion Blur is on). |
| Volume Density | Global render density/extinction multiplier (thicker or thinner look) without re-simulating. |
| Blend Mode | Normal (premultiplied) or Additive (fully visible glow). |
| Blend Strength | Mix amount for the chosen blend mode. |
Tips
Getting started & running Pyron
Start from a Preset — the fastest way in. Apply Pyron, open the Presets tab, pick a look, then fine-tune.
Design at Small — and Small renders great too. It's plenty for most fire. Only reach for Tiny when you want extra detail, and use it for the final render only, never while editing. (See Performance.)
Feels frozen at Tiny? It isn't crashed — the GPU is catching up. Wait, or edit at Small. Turning off Cache Frames When Idle helps.
Scrub gently — it's a real simulation. Jumping around the timeline forces a re-sim; play or scrub in order for the smoothest preview.
Diagonal watermark = trial mode. Click Options, paste your key, Activate — it clears instantly. (See Registration.)
Building the look
Apply Pyron to a black solid, not directly to your footage. The simulation needs its own canvas — composite the result over your footage with a blend mode (Add / Screen).
Burn a logo or text: assign it as the Source Layer. Its alpha becomes the fuel. Keyframe Burn Progress 0 → 100% to animate the reveal, and pick a Burn Mode (Directional / Radial / Dissolve / Iris) for the style.
Free-standing flame: use the Source Position point + sphere emitter. Move the point in the comp; raise Trail and enable Path Emitter for a flame that follows the motion.
This is a real simulation — motion needs a few frames to settle. It can't start or stop instantly. Plan your animation around that rhythm.
Parameters are coupled. After changing one (e.g. Buoyancy), scan the panel and rebalance the rest (Turbulence, Life, Speed).
Buoyancy is the main rising force. Add life with Turbulence + Turbulence Scale, then hold the swirls with Vorticity — vorticity amplifies existing motion, it doesn't create it.
For realistic fire use Blackbody color; set Min / Max Color Temp in Kelvin. For stylized looks switch Color Mode to Custom and set the Source (core) and Mid colors.
Sharper, more defined flames: open the Sharpness tab — raise Density Contrast, set Edge Sampling ▸ Ultra Sharp, and push Flame Aggression.
Direct the smoke with a comp light. Add an AE Light and set Key Light to it (or Auto) for directional shading and depth.
For curved flame paths, use a mask. Draw a mask path, copy it, and paste onto Source Position as keyframes.
Detail comes from parameters, not comp resolution. Switching the comp to 4K won't add fluid detail — use Voxel Size, Turbulence and the Sharpness tab.
Multiple Pyron layers work, but each adds its own GPU cost. Design one layer, then duplicate for richer choreography.
Working in HDR / 32-bit? Pyron renders true 32-bit float. After changing project depth, purge the cache (or nudge a parameter) so stale frames refresh.
Performance
Pyron is a true volumetric GPU simulation. Two independent controls shape performance:
- Voxel Size (Simulation) — the 3D grid resolution of the fluid solve. The main driver of simulation speed. Finer grids = more detail, much heavier.
- Quality (Render) — render-side detail (anti-aliasing and ray-march sampling). Affects how the volume is drawn, not how it is simulated.
🔥 Important — Voxel Size & your hardware
Small is the recommended everyday Voxel Size — great for most fire and responsive to work with.
- Small renders great on its own — reach for Tiny (the heaviest grid) only when you want extra detail, and only for the final render, never while editing.
- Small and Tiny want a strong GPU; Tiny especially needs plenty of VRAM. If a frame comes back empty, drop to Small — it recovers.
- Mac: Apple Silicon M3 Pro or above recommended (especially for Tiny). On M1 / base chips, stay on Small / Medium.
💡 Snappier editing: turn off Composition ▸ Preview ▸ "Cache Frames When Idle" while you work — Pyron then gives the GPU to the frame you're viewing instead of pre-rendering ahead. Re-enable it for smooth RAM previews.
ℹ️ Note: changing the Voxel Size changes the simulation grid, so the look can shift slightly between a light editing grid and the final one — always do the final render at your chosen Voxel Size.
Windows
- Performance scales with your GPU. A dedicated NVIDIA / AMD card is dramatically faster than integrated graphics.
- More VRAM allows finer Voxel Sizes without running out of memory.
- Keep the GPU driver up to date for best OpenCL performance.
macOS (Apple Silicon)
- Mac is significantly slower than Windows for this kind of GPU compute — plan a larger Voxel Size accordingly.
- M1 / base Apple Silicon: works, but use a larger Voxel Size — at the finest grids it becomes very slow.
- M3 Pro and above (recommended): handles finer Voxel Sizes comfortably for detailed fire.
- As on Windows: design at a light Voxel Size, switch to a finer grid + Ultra only for the final render.
Troubleshooting
The effect renders solid red
Pyron could not initialize the GPU. Update your graphics driver and confirm your GPU supports OpenCL (Windows) or Metal (macOS). See System Requirements.
After Effects freezes while editing at the Tiny Voxel Size
At the finest Voxel Size (Tiny), every simulated frame is very heavy to compute. If you change several parameters in quick succession — or if After Effects is pre-rendering the timeline in the background ("Cache Frames When Idle") while you edit — the GPU becomes saturated and the interface can appear frozen for a while. This is not a crash: the queued work is still being processed, and Pyron recovers on its own once it finishes.
- Wait for the queued processing to finish — playback/scrubbing resumes by itself.
- Or close and reopen After Effects to clear the queue immediately.
- To avoid it: edit at Medium Voxel Size (or Small on a fast GPU/CPU), and switch to Tiny only for the final render when you need maximum detail. Turning off Composition ▸ Preview ▸ "Cache Frames When Idle" while editing also helps a lot.
Output is black / nothing renders
Make sure there is an emission source: either a Source Position in frame with a sphere emitter, or a valid Source Layer whose alpha is non-empty. Check that Opacity and Intensity are above 0.
The fire doesn't follow my logo / Source Layer (or the logo shows through)
Pyron emits fire from the source layer's alpha — it is used as fuel, not composited as an image.
- Assign the layer in Pattern Type ▸ Source Layer, and make sure it actually has alpha. A full-frame solid has no alpha edges, so it won't seed a logo shape.
- Only the alpha is used; the source layer's own RGB is not drawn by Pyron. To also see the logo itself, keep it as a separate visible layer (or composite it separately over the fire).
- If the fire is offset, scaled wrong, or misbehaves with transforms, nest the source layer in a comp-sized pre-composition and point Pyron at that precomp.
A reshaped path still burns the old trail
After you edit a motion path (the Source Position or a light path), Pyron normally refreshes automatically. If an old trail lingers, nudge any parameter or purge the cache (Edit ▸ Purge ▸ All Memory & Disk Cache) to force a clean re-render.
Slow preview / timeline scrubs slowly
Lower the Voxel Size while editing and turn off Cache Frames When Idle (see Performance). Heavy fire on a deep timeline at the finest grid is compute-intensive by nature.
The look shifts when I change Voxel Size
Expected — Voxel Size changes the simulation grid. Choose your final grid before final render.
Looks wrong / stale in a 32-bit project after changing depth
Pyron fully supports 8, 16 and 32-bit (float). If switching project depth leaves stale cached frames, purge the cache (Edit ▸ Purge ▸ All Memory & Disk Cache) or nudge any parameter to force a clean re-render.
Registration dialog keeps appearing
Re-enter your license key and click Activate while online. If it persists, contact ycraft.apps@gmail.com — include the key you purchased with.
Updates
Updates are free and use the same download page as the trial:
- Apply Pyron, open Options → click Check for Update. If a newer version exists, the button becomes Get Update and opens the download page.
- Download the latest ZIP from ycraft.dev/get-pyron.
- Replace
Pyron.aexin your plug-ins folder with the new one (same steps as Installation) and restart After Effects.
Your license stays active after an update — no need to re-enter your key.
System Requirements
- Host: Adobe After Effects 2021 or later (64-bit).
- OS: Windows 10/11 (64-bit) or macOS (Apple Silicon).
- GPU: A GPU with up-to-date drivers — OpenCL on Windows, Metal on macOS. More VRAM allows finer Voxel Sizes.
- Color depth: 8, 16 and 32-bit (float) projects all supported.
Support
- Product page: ycraft.dev/pyron
- Downloads & updates: ycraft.dev/get-pyron
- Bug reports / questions: ycraft.apps@gmail.com