MAST snaps your modular assets to a grid so you can build scenes and levels at the speed of thought.
Unity 6+ · URP and Built-in · free · MIT licensed
Stop dragging prefabs one at a time
MAST is a Unity editor extension for staging modular 3D assets. Instead of positioning prefabs by hand, you pick from a thumbnail palette and paint the level in — clicking, sweeping and stacking on a grid. It works with any prefab, so game-ready objects keep their scripts, lights and colliders, and when the scene is done it can merge the static meshes into an optimised prefab.
Ghost previews
See the piece before you commit it, with rotation, flipping and randomisation on the way down.
Collision detection
Pieces refuse to overlap by accident, so a sweep across a floor doesn't quietly stack six copies.
Face-based building
Build off any face and manipulate the grid at any angle — not just the world axes.
Material painting
Paint materials straight onto placed geometry, with undo, and restore the original in one click.
Merge & make prefabs
Collapse a finished section of static meshes into a single optimised prefab when you're happy.
Rebindable everything
Every hotkey is rebindable and the interface is configurable, because everyone's muscle memory is already spoken for.
Screenshots
Click any shot to enlarge it.
Details
| Unity version | Unity 6.0 or newer |
|---|---|
| Render pipelines | URP and Built-in |
| Price | Free — name-your-own-price, with nothing held back |
| Licence | MIT, open source |
| Works with | Any prefab, including game-ready objects carrying scripts, lights and colliders |
| Status | Maintenance mode — it does what it was built to do, and it's yours to fork |