How to Design Your First MOC: A 10-Step Guide From Idea to Instructions

Every builder reaches the moment where the instructions aren't enough anymore. You look at a set and think "I'd have done that roof differently", or you see a building on holiday and want it on your shelf. That's the start of your first MOC, short for My Own Creation. This guide takes you from that first idea to a model that holds together, looks great, can be built by someone else, and can be ordered brick by brick. No talent required, just a method.

Digital or physical? Choosing your tools

You can design with real bricks on a table, or with virtual bricks on a screen. Most experienced designers do both: they sketch digitally and test tricky sections with real parts.

Our recommendation for a first MOC: design in Studio. You never run out of parts, you can undo anything, and when you're done you can export a part list in one click. Before you start, load the BuyMeBricks Studio palette: it contains only part-and-colour combinations we can actually send you, over 35,000 of them. It's the single best way to avoid designing something you can't build.

Step 1: Pick the right first subject

Your first MOC should be small enough to finish and personal enough to care about. Unfinished mega-projects are the number one reason new designers give up. Good first subjects:

• A building you know: your favourite café, your grandparents' house, a corner shop from your street.
• A vehicle: a van, a tractor, a small boat. Vehicles teach proportion and angles fast.
• A vignette: a tiny scene on a 6×6 or 8×8 base. Big storytelling, few parts, and a fantastic way to practise detail.
• An object from your desk: a camera, a plant, a typewriter. Life-size objects are surprisingly forgiving.

Aim for 200 to 600 pieces. Big enough to be satisfying, small enough to finish in a few evenings.

Step 2: Choose a scale (with the maths)

Scale decides everything else: how big the windows are, how many parts you need, how much it costs. Decide it first, and write it down.

The quick formula: real size ÷ scale ÷ 8 mm = studs. A 4.5 m long van at minifig scale (roughly 1:40) is 4,500 ÷ 40 ÷ 8 ≈ 14 studs long. At 1:20 it would be 28 studs. Do this for length, width and height, and you'll have a bounding box before you place a single brick.

Common scales: microscale (a whole skyline on a baseplate), minifig scale (figures fit inside, roughly 1:35 to 1:45), and display scales like 1:20 or 1:12 for vehicles and objects.

Step 3: Collect references

Great MOCs look "right" because the designer studied the real thing. Gather 10 to 20 photos before you start: front, side, back, top if you can, and close-ups of the details that make it recognisable. A shared board or a folder on your desktop is enough. Pay special attention to:

• The silhouette. If the outline is right, people recognise the subject even with almost no detail.
• The two or three signature details: the round window, the striped awning, the chunky front grille. These matter far more than accuracy everywhere else.
• The proportions. Measure ratios (height vs width) on the photo and keep them in your model.

Step 4: Block out the shape

Sculptors start with clay, not with eyelashes. Do the same: build the rough volumes first with big, simple bricks in any colour. A building becomes a few boxes; a vehicle becomes a chassis, a cabin and wheels. Then look at it from a distance (or zoom out in Studio). Does the silhouette read? Are the proportions right? Fixing a block-out takes minutes; fixing a finished, detailed model takes days.

Step 5: Build a strong core

A model that looks great but falls apart when someone lifts it is a model nobody will build twice. Strength comes from the inside:

• Overlap your bricks like a real brick wall. Stacked columns of the same brick split apart; staggered joints lock together.
• Use long plates as beams. A layer of overlapping long plates under a floor or along a chassis turns many small sections into one solid piece.
• Technic bricks and pins add serious rigidity to long or tall models, and can be hidden inside.
• Build in modules. Floors that lift off, a body that slides onto a chassis. Modules are easier to build, to display and to explain in instructions.
• Keep attachment points generous. A detail held by one stud will be the first thing to fall off in the box.

Legal and "illegal" connections

Builders call a connection "illegal" when it forces parts into positions that stress them: wedging a plate between studs, bending a part to make it fit, or relying on a gap that only works because of tolerance. They might hold today, but they stress the plastic, may not fit in another batch, and frustrate whoever builds your model. Official-quality designs avoid them, and so should yours, especially if you plan to share or sell your MOC.

Step 6: Choose your colours

Beginners tend to use every colour they have. Experienced designers use few. A limited palette looks intentional, photographs better and is easier to source.

• The 60-30-10 rule: one dominant colour (about 60% of the visible surface), one secondary (30%) and one accent (10%). It works for interiors, and it works for bricks.
• Use darker tones low and lighter tones high. It makes models feel grounded and stable.
• Greys and tans are your friends for roofs, roads, stone and machinery. They make the accent colours pop.
• Hide structural parts in any colour, but only where nobody will ever see them, and keep them in common colours so the model stays easy to source.
• Avoid rare colours for big areas. A wall in a colour that exists in only a handful of parts will force compromises everywhere.

Step 7: Detailing techniques that level you up

Detail doesn't come from adding more bricks. It comes from building in more directions and using parts in unexpected ways. Here are the techniques that separate a first MOC from a great one.

Learn by studying others. Browse the MOC Store and look closely at how other designers solve corners, roofs and windows. Every great designer started by borrowing techniques, then made them their own.

Step 8: Stress-test your model

A digital model can't fall over. A real one will. Before you call it finished:

• Check for floating parts. In a digital model, parts can hang in mid-air without being connected. Rotate the model and look underneath; Studio's collision check helps spot parts that overlap.
• Build it for real if you can, at least the risky sections: long overhangs, thin towers, anything on a hinge.
• The "lift and swoosh" test: pick it up by the place a person naturally would. Does anything bend, creak or drop?
• Hand it to someone else. Watch where they struggle. That's where your instructions or your structure need work.

Step 9: Make sure every part exists

This is the step that catches almost every first-time designer. A digital library contains parts in colours that were never produced, or haven't been available for years. Your model might be perfect on screen and impossible to build in real life.

1. Export the part list from Studio (BrickLink XML) or Rebrickable (CSV).
2. Upload it on our upload page. In seconds you'll see which parts are in stock, the ones that aren't, and the total price of the model.
3. Swap the missing parts for available ones, using the Studio palette to see which colours each part comes in, then re-upload.

Our Studio and Rebrickable tutorial walks through it with screenshots. It's also a reality check on cost: if your 600-piece model costs more than you expected, look for big areas built from lots of tiny parts and simplify them with larger plates or bricks.

Step 10: Make instructions people can follow

If you want anyone else to build your MOC (a friend, your followers, or paying customers) the instructions matter as much as the model. Studio's built-in instruction maker does most of the work. These habits make the result feel professional:

• Three to eight new parts per step at the start, a little more once the builder knows the model. Never make people hunt for a tiny part hidden behind a big one.
• Use submodels for repeated or separate sections (wheels, windows, a tree). Build them once in a callout, then attach them.
• Rotate the view whenever the next part goes on the side or back. A builder should never have to guess where something goes.
• Show the parts list for each step, and put a full bill of materials at the end.
• Add a cover page with a render of the finished model, its piece count and dimensions.
• Test-build from the PDF, not from memory. You will find at least one step that makes no sense. Everyone does.

10 beginner mistakes (and the fix)

MOC glossary

MOC

My Own Creation: any model you designed yourself.

SNOT

Studs Not On Top: building sideways or upside down.

NPU

Nice Part Usage: a part used creatively for something else.

Greebling

Small parts layered to suggest technical detail.

Jumper

A plate with one central stud, used for half-stud offsets.

Vignette

A small scene on a tiny base, often 6×6 or 8×8 studs.

Modular

Sections designed to connect to each other or lift apart.

BOM

Bill of materials: the full part list of a model.

Illegal connection

A connection that stresses or bends parts to make them fit.

WIP

Work in progress: what you post to get feedback.

FAQ

What is the best free software to design a MOC?

Studio is the most complete free option for most people: a huge parts library, an instruction maker, photo-realistic renders and part list export. Mecabricks runs in a browser, and LeoCAD and LDCad are open-source alternatives.

How many pieces should my first MOC have?

Between 200 and 600 pieces is a good target: big enough to be satisfying, small enough to finish in a few evenings.

How do I know if the parts in my design actually exist?

Export the part list from Studio or Rebrickable and upload it on the BuyMeBricks upload page. You'll see in seconds which parts are in stock and the price of the whole model. Designing with the BuyMeBricks Studio palette avoids the problem from the start.

What does "illegal" building technique mean?

A connection that stresses or bends parts to make them fit, or relies on a gap that only works by luck. It may hold, but it can damage parts and doesn't work reliably for other builders.

Can I sell instructions for my MOC?

Yes, as long as the design is original and doesn't use other companies' trademarks or characters. On the BuyMeBricks MOC Store you can publish it for free or with a designer fee, and builders can order the parts in the same click.