Sprite Animation Toolkit

Sprite Animation Toolkit is a Unity Editor tool that turns grid-based spritesheets into frame-by-frame AnimationClips and connects them to your Animator Controller in one step.

Define a sheet layout once — frame size, slicing direction, pivot, import settings and the animation table — save it as a preset, and reuse it for every spritesheet that shares that layout. A single click on Build & Sync Animator slices the texture, creates or updates the clips, and assigns them to Animator states. Regeneration updates existing assets in place, so prefabs, controllers and scenes that reference them keep working.

Designed for 2D and pixel-art projects, it works with any frame-by-frame animation arranged on a regular grid.

How it works

1. Select a spritesheet and, optionally, an Animator Controller or Animator Override Controller.

2. Set frame size, grid offset, cell padding and pivot — or load a preset. Auto-Fill From Grid fills the animation table from the grid.

3. Define animations per row (or per column): clip name, target state, frame count, sample rate and loop.

4. Click Build & Sync Animator: the texture is sliced, clips are generated or updated, and assigned to their states.

5. Review the generation report and preview each state's animation.

Only the states listed in the animation table are touched. Missing states are added to the controller's base layer; transitions, parameters and all other states stay unchanged. With no controller assigned, the tool generates clips only.

Features

Slicing & import

* Slice grid-based spritesheets by rows or by columns

* Frame size, grid offset, cell padding, pivot presets or a custom pivot

* Auto-Fill From Grid detects how many animations and frames fit in the texture

* Optional texture import settings (Pixel Art profile, PPU, filter mode, compression and more), with a list of planned importer changes shown before anything is written

Clips & Animator

* Generate AnimationClips with per-animation frame count, sample rate and loop setting

* Assign clips to existing Animator states or create missing states automatically

* Share one clip between several states

* Write clips into an Animator Override Controller without modifying the base controller

* Choose the output folder and clip naming scheme

* Safe regeneration: existing clips are updated in place and sprite IDs stay stable, so references survive

* Overwrite / Skip / Overwrite All confirmation for existing clips

* Warnings for clips that are no longer referenced — nothing is deleted automatically

Presets

* Save slice settings, import settings and the animation table as reusable preset assets

* Modified fields are highlighted; restore a single value (right-click) or all of them at once

* Confirmation before loading another preset over unsaved changes

Preview & validation

* Preview the clip of any Animator state with play/pause, restart and frame-by-frame stepping

* With an Override Controller assigned, the preview shows the overriding clip, falling back to the base clip

* Detects keyframes with missing sprites

* Live validation keeps Build & Sync disabled — and explains why — while the setup can't produce valid clips

* Color-coded generation report, copyable to the clipboard

Preview actual controller output

Select an Animator state to preview the clip it actually plays. When an Animator Override Controller is assigned, Sprite Animation Toolkit resolves each state through the override, making it easy to verify character variants, alternate skins or equipment sets without hunting for individual clips.

Designed for repeatable workflows

Useful whenever a character, enemy, prop or visual effect has several animations laid out in spritesheet rows — idle, walk, run, jump, attack, hurt, death. Instead of repeatedly slicing artwork, creating clips, finding Animator states and assigning motions by hand, load a preset, assign the sheet and rebuild — whenever the artwork changes or a new variant with the same layout arrives.

Typical use cases

* Pixel-art characters and enemies

* 2D action, platformer, RPG and roguelite projects

* Animated props and sprite-based visual effects

* Multiple character or equipment variants sharing one sheet layout

* Animator Override Controller workflows

* Teams that need predictable clip naming and state assignment

Included sample

Basic Spritesheet Demo — a slime spritesheet with Idle, Jump and Die animations, a preset, an Animator Controller and a ready-to-play scene.

Requirements

* Unity 2022.3.42f1 or newer (tested on Unity 2022.3 and Unity 6.3)

* 2D Sprite package (com.unity.2d.sprite) installed in the project

* A grid-based spritesheet texture (PNG recommended)

* Generated clips animate SpriteRenderer.sprite; the Animator and SpriteRenderer must be on the same GameObject (UI Image is not supported)

Sprite Animation Toolkit is Editor-only. It generates standard Unity assets (sprites, AnimationClips, Animator states) and adds no runtime code to your builds.