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PostRoll Help

Presets and effects

A preset is a named recipe that turns a plain light into a torch, a pulsing magical aura, a sunbeam through a window, or a stage-style key light. Presets bundle together animation, colour shifts, and shaping into a single drop-down choice — and you can stack your own effects on top.

This page covers how to apply presets, what each effect primitive does, and the per-light colour-grading knobs.

Applying a preset

Section titled “Applying a preset”

In the Light Tool’s Animation tab → Preset select, you’ll find recipes grouped by namespace:

  • foundry/ — Foundry-equivalent recipes (Torch, Pulse, Dome, Sunburst, Revolving, …). Useful when importing scenes from Foundry.
  • postroll/ — Postroll originals (Eldritch, Aurora, Will-o-the-wisp, …). Authored to feel native.
  • cinematic/ — Stage-lighting recipes (Key, Fill, Rim, Candlelit-room, Theatrical-spot, Eldritch-altar, Daybreak-window, …). Authored for set-pieces and posed scenes.

Picking a preset replaces the light’s effect stack with that recipe. Unsaved per-light tweaks below (effects, animation modifiers) get blended in on top.

What an effect stack is

Section titled “What an effect stack is”

Underneath every preset is a list of effect steps — small reusable shader fragments that combine to produce the final look. The stack is visible (and editable) below the preset picker, listed in execution order.

Each step has:

  • A primitive type (the kind of effect)
  • Parameters specific to that primitive
  • An optional speed and intensity multiplier
  • An optional reverse flag (plays the animation backwards)

You can add, remove, or reorder steps to build your own animations.

The primitives at a glance

Section titled “The primitives at a glance”
Primitive What it does Typical use
BasePulse Radial intensity pulse — sin / noise / expanding ring Heartbeat, magic charging, throb
ColorCycle Animated hue rotation Rainbow, faerie fire, chroma
NoisePattern Perlin / simplex noise overlay Flicker texture, ripples, organic feel
RadialMask Polar-coordinate falloff curve Custom radius shaping (sun rays, spotlights)
ShapeWarp Distort the boundary with directional sweep Wobbly ghost light, lens shimmer
GridOverlay Scanline or grid pattern Sci-fi force fields, holograms
ColorBlend Apply one of 19 blend modes (overlay, soft-light, hue, exposure, …) Subtle tint, dramatic re-grading
GoboProjection Project a stencil through the light Window blinds, leaf dapple, runes, cathedral rose

For ColorBlend, available modes are: multiply, screen, overlay, softLight, hardLight, colorBurn, colorDodge, linearBurn, linearDodge, lighten, darken, difference, exclusion, hueOnly, saturationOnly, luminosityOnly, vibrancy, exposure, plus a passthrough.

For GoboProjection, available stencils today are: blinds, crosshatch, leafDapple, cloudShadow, rune, chainLink, brick, plus a passthrough.

Building your own stack

Section titled “Building your own stack”

To build a custom torch from scratch:

  1. Set Preset to None.
  2. Add a BasePulse step with mode noise and a small amplitude.
  3. Add a ColorCycle step with low speed for subtle flame-colour drift.
  4. Add a NoisePattern step at a fine scale for the flicker texture.
  5. Tweak the per-step speed and intensity to taste.

If you save this often, see Tags and preset packs for exporting it as a reusable pack.

Per-light colour grading

Section titled “Per-light colour grading”

The Color tab has four knobs that grade the light’s contribution after the effect stack runs:

Knob Range Effect
Attenuation 0..1 Adjusts the falloff curve (steeper or shallower fade).
Saturation -1..1 -1 = grey, 0 = identity, 1 = oversaturated.
Contrast -1..1 Stretch / compress the brightness range.
Shadows 0..1 How much shadow detail bleeds through.

These knobs apply per-light, so you can grade one torch warm and another cool without touching the scene-wide mood.

Negative lights

Section titled “Negative lights”

The Negative switch (or Luminosity < 0) inverts the light into a darkness emitter — it pulls light out of the scene instead of adding it, useful for spell effects like Darkness or for shaped shadow zones inside an otherwise lit area.

The strength of the negative effect is |luminosity| clamped to 1.

Scene blend mode

Section titled “Scene blend mode”

In the Advanced tab, Blend mode controls how this light composites onto the lighting layer:

Mode Result
add (default) Brightens — additive lighting.
screen Softer than add; doesn’t blow out as easily.
normal Paints opaque colour.
multiply Darkens — like a shadow projector.
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