Mecabricks is a free editor for building digital LEGO models in a web browser, and one of the main routes to photorealistic LEGO renders through Blender. It describes itself as a way to build and render 3D LEGO models online, with no plug-in or installation: you make an account and start building. This guide covers what it does well, where its free and paid parts begin, and how to get a design out of Mecabricks and onto your table as real bricks.
Quick answer: use Mecabricks to build in the browser and to render through Blender with its free Blender Lite add-on, upgrading to the paid Blender Advanced add-on only if you want its extra materials and part packs. When the model is done, export the parts list as BrickLink XML from the model page's Inventory tab. For printed building instructions, BrickLink Studio is the better tool.
What Mecabricks is
Mecabricks is a browser-based LEGO CAD tool. You build in the workshop by choosing parts from its library, placing them, and changing their colors, then save the model to your account. Models can be shared publicly, and every public model has its own page with a 3D viewer and an inventory of the parts it uses.
Because it runs in the browser, it works the same way on any computer with a modern browser. The tradeoff is that large models ask more of your machine, and the most polished images come from exporting to Blender rather than from the browser.
Getting started
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Create a free account on the Mecabricks site. You need it to save models.
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Open the workshop and pick parts from the library. Each part can be colored before or after you place it.
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Build in small groups. Assemble a wall, a window or a roof section, then move it as a unit. That keeps a big model manageable.
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Save often, and publish the model when you want its public page and inventory.
If you are planning your first design, our guide to planning your first MOC covers the steps before you open any software.
Importing models you already have
Mecabricks imports LEGO Digital Designer and LDraw files. Those formats store which parts go where, not the shapes of the parts themselves, so Mecabricks rebuilds the model from its own library. A Mecabricks moderator explains the catch: if a part does not exist in Mecabricks yet, it cannot be imported, and the browser console shows which parts failed.
If you work with LDraw files, our free LDraw Model Checker lists a model's parts with catalog links and shows which bricks connect, and the LDraw 3D Viewer lets you turn a model around and step through its build in the browser.
Rendering with Blender
Blender is a free, open-source 3D program, and Mecabricks connects to it through add-ons sold in its own shop:
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Blender Lite is free. It brings Mecabricks models into Blender scenes.
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Blender Advanced is paid. Mecabricks lists high-resolution part packs, optional real geometry bevels, scratches and fingerprints, automatic detection of stickers and printed areas, instancing to keep memory use down, and support for CPU and GPU rendering (CUDA, OptiX and Metal). Its product page lists support for Blender 2.80 to 5.1, and Mecabricks says future versions are free for current buyers.
The shop also sells other paid add-ons, so check what each one covers before buying. For the wider picture of LEGO rendering, including Studio's own renderer and LDraw options, see our guide to rendering photorealistic images of MOCs.
From the screen to real bricks
The most useful step for a physical build is the parts list. On a public model's page, not in the workshop, the Inventory tab exports the parts as a CSV file or as BrickLink XML. The XML can go straight into a BrickLink Wanted List, which lets BrickLink find stores that stock the parts. Our BrickLink buying guide explains Wanted Lists and how to keep an order to a few stores, and our guide to sourcing parts for a MOC compares BrickLink with LEGO's own Pick a Brick.
Two habits save money. Check colors against what LEGO actually makes, because a digital model can use a part in a color that is hard or impossible to buy. And before ordering, compare the list with the parts you already own; our Sorting Planner helps organize a collection so that check is quick.
Mecabricks, Studio or LDraw?
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Mecabricks suits building anywhere in a browser and rendering through Blender.
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BrickLink Studio is a free desktop program for Windows and macOS from the LEGO Group, with its own photoreal renderer and an instruction maker. Our BrickLink Studio tutorial covers it.
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LDraw tools such as LeoCAD and LDCad build on the open LDraw parts library, which many other programs read. See our LDraw tutorial.
None of these is a dead end. Mecabricks reads LDD and LDraw files, Studio imports several formats, and many builders design in one tool and render or document in another.
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