James MarlandTechnical Artist - Tools, Pipelines & Shaders

November 2025

Tool Brick

A start-to-end procedural LEGO building tool for Unreal, with 945 parts that snap together by their studs. Released on GitHub.

Emmet's bedroom built from LEGO bricks, warm light from an arched window falling across a studded yellow floor, with a bed, a red wardrobe, a bike, a computer on a round table and a digital clock reading 12:01

Breakdowns

4 deep dives into the parts I built.

  1. A folder of grey 128px part thumbnails beside the terminal logging each download
    01Python and LDraw dataI wrote one script that sifts LDraw's 23,000+ parts down to the 945 worth building with, and makes a browser thumbnail for 720 of them.
  2. The underside of a quarter round part in Houdini, green points marking every anti-stud position
    02Houdini PDG and the stud algorithmOne PDG network builds all 945 parts with Stefan Müller's LDraw2Houdini, then my stud algorithm raycasts each one to find where other bricks connect.
  3. Rows of 2 x 2 bricks in every solid, transparent, glitter, pearl and metallic colour against a blue sky
    03The Unreal toolsetThe in-editor toolset artists build with: search, 73 colours and stud snapping, holding 92.9 FPS with 6,406 actors in the editor.
  4. A low angle across Emmet's studded LEGO floor towards the bed, a green blanket catching the lamp light and the clock reading 12:01 behind it
    04Emmet's apartmentI rebuilt Emmet's bedroom from The LEGO Movie brick by brick with my own tool, in 5 hours including lighting and camera.

Overview

Tool Brick is an Unreal Engine 5 tool for building environments out of LEGO bricks inside the editor. I made it over 8 weeks for my final year Advanced Specialism module at Escape Studios and released it on GitHub. It’s aimed at rendered work like brickfilms, but could be adapted for real-time use.

It started as a reaction to LEGO’s brick-by-brick mode in UEFN, which gives you around 50 preset parts and a clean look that suits Fortnite (Epic Games and LEGO Group, 2025). I wanted the realism of The LEGO Movie (The LEGO Movie, 2014) instead, scratches and fingerprints included. Animal Logic built the film’s sets in LEGO Digital Designer (Fxguide, 2015), and my idea as a TA was to move that step into the engine, so artists don’t have to export, import and set up parts by hand.

Building the showcase set, sped up.
The Unreal editor with the Tool Brick panel docked on the left, a grid of colour swatches above a searchable list of slope parts, and the finished bedroom set lit warm orange in the viewport
The full showcase: the browser, colours, snapping, the test levels and the apartment.
Setting it up, with every Python stage run on camera.

Get it

Everything is on GitHub under a CC BY-NC 4.0 licence, including an Unreal 5.5 project with the tool, the generated part library and the showcase level. You can also download my full written breakdown.

Tool Brick on GitHubProject breakdown (PDF)

Reflections

I hit every goal I set myself at the start, from the editor tool through to an environment built with it.

The biggest weakness was building it all in Blueprint. Editor utilities and JSON handling don’t give you enough control, and I kept having to write workarounds. Written in C++ it would probably have been a smaller tool, but a much better integrated one.

If I came back to it, I’d move the snap handles inside the brick as components, and generate parts on request through Houdini Engine instead of baking the whole library up front. I’d also like to build the smaller tools I dropped from my original brief to focus on the core, like placing fences, rocks and walls from a few settings instead of brick by brick.

Tool Brick wouldn’t have been possible without LDraw (LDraw.org, 2002) and Stefan Müller’s LDraw2Houdini (Müller, 2023). The thumbnails come from Rebrickable, the surface textures in the master material are credited on the Unreal toolset page, and everything else is credited on the project’s GitHub.

Tool Brick is released under the CC BY-NC 4.0 licence.

LEGO® is a registered trademark of the LEGO Group, which does not sponsor, endorse or authorise this tool. Visit the official LEGO website at lego.com.

Sources