Scatter — Quick Start

What is Scatter?

Scatter (ABS_Scatter.lua) solves a specific, recurring problem in sample-based production: assigning randomized audio files to child tracks without broken paths, duplicate picks, or manual drag-and-drop.

You define a library directory and per-track file filters. Scatter scans the directory, applies your filters, and assigns one file per track per roll — at the edit cursor, non-destructively, with full REAPER undo support.

The result: a new, randomized variation of your layer stack in a single keystroke.

Before You Start

Ensure the following are installed:

  • REAPER 7.x
  • ReaImGui 0.9.x (required for the GUI)
  • Scatter installed via ReaPack or manual install — see Installation Guide

Basic Workflow

1. Set up your track hierarchy

Scatter works on a parent track with child tracks. Each child track represents one layer that will receive a file.

Parent: Kick Layers
  ├── Child 01 — receives one kick sample
  ├── Child 02 — receives one kick sample
  └── Child 03 — receives one kick sample

Select the parent track in REAPER before opening Scatter.

2. Place the edit cursor

Position the edit cursor at the point in your timeline where you want items inserted. Scatter inserts items at the cursor position.

3. Open Scatter

Open the REAPER Actions list (?), search for ABS_Scatter, and run it. Assign it to a shortcut (e.g., Alt+S) for fast access.

4. Set your library root

In the Scatter window, set the Library Root — the top-level folder containing your samples. Scatter scans this directory recursively.

Screenshot placeholder: Scatter window with Library Root field.

5. Set per-track filters (optional)

Each child track can have its own filter string. Scatter matches files where the filename contains the filter text (case-insensitive).

Examples:

  • kick_hard — only files containing "kick_hard" in the name
  • room — only files with "room" in the name
  • (empty) — any file in the library root

6. Choose an assignment mode

| Mode | Behavior | |------|----------| | FREE | Each track picks independently. Duplicates across tracks are allowed. | | UNIQ | Each track gets a unique file. No file appears on two tracks in the same roll. | | LOCK | Track keeps its current file. Excluded from the roll. |

7. Roll

Click Roll All (or press Enter). Scatter assigns one file per track at the cursor position, colored by track, with inline result counts shown in the window.

To roll again and get a new variation, click Roll All again. Each roll is a separate REAPER undo point — use Ctrl+Z to step back through variations.

Example Use Cases

Layered drum variation

You're building a layered kick with 3 elements (sub, transient, room tail). Each has a folder of 20–30 variations.

Setup:

  • Parent: Kick
  • Child 01, filter: sub
  • Child 02, filter: transient
  • Child 03, filter: room
  • Mode: UNIQ

Each Roll gives you a fresh combination. 20+ variations in under 30 seconds.

Foley randomization

You have 50 footstep files and need to fill 8 tracks for a walking sequence.

Setup:

  • Library root: Footsteps/
  • All 8 children, no filter
  • Mode: UNIQ

Each roll produces 8 non-repeating footsteps. Roll across multiple cursor positions to build a full walking cue quickly.

Locked reference layer

You've found the perfect sub, but want to keep rolling the transient.

Setup:

  • Child 01 (sub): mode LOCK
  • Child 02, Child 03: mode FREE or UNIQ

Scatter skips locked tracks entirely. Your sub stays put.

Saving Presets

Once you've configured filters and modes for a session, save the configuration as a named preset. Presets survive project changes and are stored in your REAPER resource path.

Click the preset name area → Save preset → name it.

Next Steps