Install
BareBlocks is free, open source (GPL-3.0), and a single Blender extension. It needs Blender 4.2 or newer (developed and tested on 5.1) and has no other dependencies.
- Download the latest
bareblocks.zipfrom the releases page. - Open Blender → Edit ▸ Preferences ▸ Get Extensions ▸ Install from Disk…
- Pick the
bareblocks.zip. - Enable BareBlocks if it isn't already on.
Find everything in the 3D viewport sidebar: press N and open the BareBlocks tab. Blocks are also under Shift+A ▸ BareBlocks.
Add a block
In the Add Blockout panel, each category shows a big thumbnail. Click it to open a grid of large icons, then click a shape to drop it into the scene.
- At 3D Cursor — place new blocks at the cursor instead of the world origin.
- Snap to Grid — round the placement to the grid size.
Edit dimensions
Every block is live Geometry Nodes — nothing is baked. Select a block and the Blockout Tools panel exposes its parameters (the same fields also appear on the modifier). Change a size, step count or radius any time and the block rebuilds instantly.
Block types
42 blocks across 11 categories. All are declared in one registry, so the palette, menu, edit panel, gizmos and AI tools stay in sync.
| Category | Blocks |
|---|---|
| Primitives | Box · Plane · Cylinder · Tube · Sphere · Cone (top/bottom radius) |
| Structural | Wall · Floor · Pillar · Sleeve (taper + skew) |
| Ramps & Corners | Ramp (run/width/rise) · Corner Curved (convex or inner) |
| Openings | Window · Doorway · Arch |
| Stairs | Stairs · Stairs Curved (spline) |
| Path | Track · Railing (spline) |
| Signage | Sign · Billboard |
| Trees | Tree + Pine · Palm · Oak · Birch · Willow · Cypress · Acacia · Cherry · Banyan · Baobab · Bamboo |
| Nature | Bush · Rock |
| Structures | Well · Bridge · Tower |
| Props | Barrier · Bench · Lamppost · Fountain |
Corner Curved is a solid rounded corner — convex by default, scooped with Is Inner. Window / Doorway / Arch leave a connected frame. Trees are presets of one generator: pick a Canopy Shape (Sphere / Cone / Column / Umbrella / Fronds / None) and set width, height, multi-trunk and droop.
BareBlocks mode & gizmos
Click Enter BareBlocks Mode at the top of the panel (or pick the BareBlocks tool from the toolbar, T). In the mode:
- Blender's move / rotate / scale gizmos stay on, and BareBlocks face handles appear on the active block.
- Drag a face handle to resize. The opposite face stays anchored; hold Alt to grow symmetrically from the center.
- Hold Shift to snap to major grid lines, Ctrl for minor lines. A header readout shows the live size (
Size X: 1.10 m). - Per-type handles — each block shows handles for its own parameters: Cylinder/Sphere/Corner Radius, Track Width / Wall Height, Stairs Width, Curved Stairs Inner Radius plus an angle dial for sweep.
Spline paths
Track, Railing, Wall and Stairs Curved follow an editable spline. Press Tab to enter Edit Mode, then drag, add or extrude control points — the profile sweeps along the path live.
- Track — a channel (floor + side walls) with optional rails and posts.
- Wall — a slab that bends smoothly (curved handles) or turns sharp corners (poly handles).
- The grid material flows along the path, so cells stay square around bends.
Grid material
All blocks share a procedural Blockout Material: a triplanar grid + checker locked to each block, so it doesn't swim when you move or rotate. Minor lines mark every cell; brighter major lines help you read distance.
| Control | Does |
|---|---|
| Color | Base block color (defaults to blueprint blue). |
| Use Grid | Toggle the grid lines on the checker. |
| World Aligned | One shared world grid instead of a per-block grid. |
| Grid Size | Cell size in metres. |
| Top Color | Optional tint on upward faces. |
Make Material Unique detaches an editable copy for the active block; Use Custom assigns your own material to the selection.
Align & distribute
Select 2+ objects and use the Align & Distribute panel — it works like Illustrator, in the view plane. In an orthographic view (numpad 1/7/3) it behaves as a true 2D layout tool.
- Align left / center / right and top / center / bottom along the screen axes.
- Distribute evenly spaces centers; the two outermost stay put.
- Align To — the whole selection's bounds, or the active object (the key object).
Bundles & assets
Turn a selection into a reusable prefab from the Bundles panel.
- Save Bundle — writes the selected objects to a
.blendin the bundle folder and marks them as assets. - Import Bundle — append a saved bundle back into the scene.
- Register Asset Library — add the bundle folder to Blender's Asset Libraries for drag-and-drop from the Asset Browser.
AI assistant
Build and edit scenes from a prompt — “a race-track loop with railings and a billboard,” then “make the walls taller.”
Setup
Paste your OpenAI API key in Preferences ▸ Add-ons ▸ BareBlocks and pick a model (default gpt-4o). The key is stored in Blender preferences and sent only to api.openai.com.
Use
- Plan — the agent returns an editable checklist. Reword a step, uncheck steps to skip them, or add your own.
- Approve & Build — it runs only the enabled steps, placing blocks live with the model's reasoning streaming into the Activity log.
- Build directly skips planning for quick edits; Esc cancels a run.
add_block, edit_block, move_block, set_color, shape_path, delete_block). Its base rules keep pieces on the ground, at human scale, evenly spaced. No packages to install — it uses Blender's bundled Python on a background thread, so Blender never freezes.Convert to mesh
When a block is final, Convert to Mesh (Blockout Tools panel) applies the modifier on the selection, turning it into a plain editable mesh while keeping the Blockout material.
FAQ
Is it really free?
Yes — BareBlocks is free and open source under the GPL-3.0. Download it, use it on any project (personal or commercial), read the source, and fork it. The only thing you might pay for is your own OpenAI usage if you use the AI assistant.
Can I contribute or report a bug?
Please do — issues and pull requests are welcome on GitHub.
Which Blender versions are supported?
Blender 4.2 and newer. It ships as the new extension format and is tested on 5.1.
Does the AI cost extra?
BareBlocks doesn't charge for it — you bring your own OpenAI API key, and OpenAI bills you for usage. The rest of the add-on works fully without a key.
Can I add my own block types?
The kit is registry-driven: a new type is one registry entry plus a Geometry-Nodes builder, and it automatically appears in the palette, menu, gizmos and AI tools.
Do blocks stay editable after I save?
Yes. Parameters are stored on the modifier and persist with the .blend; blocks also auto-upgrade when the node groups change in an update.
Is it destructive?
Never, until you choose. Everything is live Geometry Nodes; Convert to Mesh bakes only when you ask.