Particle guide
Browse Particle controls by UI section
Particle controls define what each particle looks like. They appear in PARTICLE for the selected system. Entropy draws the selected particle type as the simulation advances.
Choose a particle type
| Particle Type | What it draws | Useful starting point |
|---|---|---|
| Sprite | A flat shape or image. | Dust, sparks, graphic shapes, image particles. |
| Geometry | A three-dimensional mesh for each particle. | Debris, beads, crystals, solid objects. |
| Volume | Density combined into a cloud or merged form. | Smoke, plumes, soft clouds, liquid-like blobs. |
| Tracer | A three-dimensional tube along particle paths. | Trails, filaments, flowing lines. |
Start with life, size, and opacity. Then tune the controls for the selected type.
Life, size, and opacity
Life (seconds) sets how long timed particles survive. Longer life keeps more particles in the scene when the creation rate stays constant. Size sets their base scale. Opacity sets their visibility.
An over-life curve changes a value as a particle ages. In Size & Opacity Graphs, choose a channel and a domain. A domain is the input that moves through the graph: particle life, or an axis of a static emitter.
For a timed particle fade:
- Select Opacity and the Life domain.
- Choose a fade-in/out curve, or draw a curve that starts low, rises, and ends low.
- Replay the system. Particles should appear and disappear gradually.
For Static emission, use X, Y, or Z to vary the result across the source. Static particles do not progress through life.
Click empty graph space to add a point. Drag a point to move it. Double-click an interior point to remove it. Reverse flips a curve horizontally; Invert flips it vertically.
Color and gradients
A gradient is a row of color stops. Entropy selects colors from that row.
| Color Mode | Result |
|---|---|
| Solid | One color swatch. |
| Gradient | A gradient sample selected by the Gradient Axis. |
| Random from gradient | A random gradient sample for each particle. |
| From Parent / Light | Color from the parent or source light. |
| From Layer | Color from the source layer. |
Gradient Axis can use Life, X position, Y position, Z position, or Index. Index means the particle's position in the sequence.
Click the gradient bar to add a stop. Use Reverse to reverse color order. Use Distribute Evenly to space stops evenly without changing their order or colors.
Sprites
Choose Circle, Square, Star, or Custom. Custom uses an assigned image from Custom Sprites. Color Apply offers None, Tint, and Fill when you need to control how particle color affects that image.
Star controls adjust two sets of rays and the center glow. Glow adds a soft halo. Drop Shadow adds an offset, softened copy behind each sprite to separate overlaps.
Geometry and materials
Choose a built-in Mesh Type, Custom for an OBJ model, or Mixed for a selection of shapes. Built-in shapes include Sphere, Cube, Pyramid, Torus, Icosahedron, Cylinder, Cone, Octahedron, and Capsule.
A material controls how the surface responds to light. Material presets set Roughness and Metallic together. Choose Custom to edit those two values yourself. Specular remains available to control highlight brightness.
Roughness changes highlight width. Metallic shifts the surface toward a metal response. Specular changes highlight brightness. These controls solve different problems.
For glass-like Geometry, increase Transmission. IOR means index of refraction; it controls how strongly light bends. Thickness changes apparent depth and absorption. White Absorption keeps glass clear. A colored Absorption produces a tint that grows with the light's path through the shape.
Dispersion separates red, green, and blue refraction. Start low. Any value above zero adds substantial glass rendering work.
Volumes
Volume Density controls optical thickness. Diffusion lets aging particles spread and become thinner. Erosion breaks up cloud edges. Metaball blends the soft density toward a merged, hard surface.
Curl controls fold the density into billows. Lower Curl Scale makes broader folds; higher values make finer folds. Curl Evolution changes how quickly the pattern evolves. These controls shape the rendered density. Turbulence changes particle motion.
Voxel Detail raises the detail budget. A voxel is one cell of the 3D volume grid. Higher detail costs more to render. Render Margin enlarges the region used to draw the volume. Increase it if the cloud clips at its bounds, then check whether fine detail remains sufficient.
Diffusion depends on age, so it does not spread a Static emitter over time.
Tracers
Tracers turn motion into connected tubes. Establish a useful particle path before tuning the tube.
Tube Sides changes the cross-section from angular to round. Taper Start narrows the oldest tail. Taper End narrows the leading tip. Trail Fade fades toward the oldest tail.
When a tracer follows its own particles, Trail Follows Forces lets the recorded trail continue moving with Wind, Vortex, and Turbulence. Turn it off to leave the recorded path in place. Geometry and Tracer surfaces share the 3D Material controls.
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