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Complete Guide on Designing a LEGO® MOC

lego moc

LEGO has a long and storied history with a variety of models and sets that you can buy off the shelf. These sets are often unique with great designs and are fun to build & play with. However, sometimes there are themes, ideas, topics and other genres that are not available in official LEGO® sets. 

Fans and enthusiasts of the hobby also tend to have certain likes and dislike about official sets which lead them to try to create something original based on their preferences and ultimately unique to their collection. These original designs and builds are what we call MOCs (My Own Creations).

Have you ever thought about creating your own LEGO® MOC?

This post shares some general information and techniques about MOCs that would help you get started designing and building the LEGO® MOC of your dreams.

What is a LEGO® MOC?

My Own Creations (MOCs), are personal designs or builds that are not part of the official sets released by LEGO® and are often inspired by an individual’s imagination, a concept, a favorite movie, a TV show, a book, or an interest.

MOCs are usually created by fans who combine LEGO® with their other hobbies or interests (i.e. characters & scenes from a movie). They are also often posted on the internet for others to enjoy (websites such as Belle-Ve Bricks, Flickr, Facebook, Instagram, etc.).

There are different ways to go about creating MOCs. Some prefer to build purely from actual bricks and experiment with the pieces they have to hand.

Others prefer to design their MOCs digitally first and use the vast unlimited supply of parts that the software offers.

Some people choose to combine digital design and physical building combining the advantages of both aspects and sometimes compromising where it is needed.

MOCs are typically created for one of three reasons:

  1. Purely for fun, LEGO® fans just simply enjoy creating MOCs either physically or digitally
  2. To share the work for free and with the satisfaction of knowing that someone has followed your instructions to build the MOC
  3. To create MOCs for the purpose of selling them; turning LEGO® into a part-time/full-time income-generating hobby. Each sale would include digital instructions as well as the parts list so the customer can easily buy the bricks from a website such as

Some examples of amazing LEGO® MOCs can be seen below. 

What types of LEGO® MOCs are there?

There are three types of LEGO® MOCs, these are modification, original designs, and alternate builds. Let’s break them down.


This type of MOC is where you take an existing official set and add parts to it to enhance its overall look and/or function without totally deviating from its original design.

An example of a LEGO® MOC that’s been modified is the modular Privet Drive which was inspired by the official LEGO® set 75968.

The below example was designed by LEGO Artisan and is available from his Belle-Ve Bricks store. You can see that the LEGO® MOC still reflected the overall look and purpose of LEGO set 75968 but it had a new layout of a modular building.

Modular Privet Drive

This type of MOC has the benefit of having a base design to start with which may help you get past the brick wall you hit when you cannot think about what to build or how to get started.

If you have looked at an official LEGO® set before and thought “wouldn’t it be great if this was added on” or “I would love it if there was a third floor to this building” then you should think about giving modification a go.

Original design

As the name suggests, this type of LEGO® MOC is when you take something from real life or your imagination and create it one brick at a time without referencing an official LEGO® set.

Original designs allow the creator to have complete free reign over the design which presents the opportunity for your MOC to be 100% unique in comparison to any other set.

It is important to say that if you intend to take your design and physically build it you need to be mindful of the bricks you use, some can be expensive to buy or really hard to find.

Good news though, is if you are using to design your LEGO® MOC it has an indicator that will highlight any pieces that are expensive. 

It is also worth keeping an eye out if the color you have picked is actually available to buy. Again, has the option to hide the unavailable colors of certain pieces.

An example of a LEGO® MOC that was created by Martin LEGO® Design can be seen below.

Tar Goroth Balrog 3

Alternate Build

An alternate build is in a way a hybrid approach to the two types mentioned above.

This type of LEGO® MOC is where you take the parts used for an official LEGO® set and create a design that is completely different from the original.

An advantage of this type of MOC is that it is easy to collect the pieces required to build your alternate build MOC. You simply just have to buy the official set from LEGO directly, Amazon, eBay, or perhaps a local store. 

The challenge therein lies with utilizing a limited resource of bricks in a certain set to create a cohesive and aesthetically pleasing design.

A sample of this type is the modular Medieval House designed by Gabizon HTBI. This LEGO® MOC is made using only the parts from the official LEGO Tree House set (21318).

medieval modular

What are the steps needed to design and build a LEGO® MOC?

Digitally designing a MOC before building it using actual bricks is an efficient way to utilize your resources. It allows you to create, adjust, modify, and experiment with the design before purchasing the pieces; therefore, avoiding any waste on unwanted pieces in your collection.

In this section of the post, we will cover what you need to get started.

  1. For digital design, a laptop or desktop PC  where or LDD software can be installed. We recommend using which is free to download from
  2. Creating and maintaining an active account on for information gathering and uploading the .IO files.
  3. Learning how to create wanted lists and ordering parts on (assuming you want to physically build your LEGO® MOC)
  4. Studying and experimenting with LEGO® building techniques
  5. Tapping into your imagination to think of awesome LEGO® MOC ideas

Tips and techniques for designing and building LEGO® MOCs

The world of LEGO® MOCs is open to all, and there are no limitations to what you can create. With the right building techniques, anything is possible.

Building with SNOT (Studs Not On Top) technique

This simply means that bricks are not vertically placed on top of each other in the traditional sense. Instead, they could be placed horizontally or at certain angles. 

Modified bricks with studs on the sides, brackets, modified plates, hinges, and other special pieces help with this technique. 

SNOT allows the designer to create textures, façade, aesthetics, and/or functions that would not be normally possible with traditional building styles.


Sometimes your LEGO® MOC will need to have words or letters incorporated into it, this is where the lettering technique comes in.

To use the lettering technique, you will need to think carefully as it can take up a lot of room if you need to spell even just a short word.

Before you commit to making letters out of LEGO® do think about whether you can achieve your goal with a custom-made sticker made instead.

SNIR (Studs Not In a Row)

Studs not in a straight row (SNIR) is a technique used when changing the depth or adjusting the location of the bricks to suit a design requirement using LEGO® pieces like jumper plates, hinges, brackets, and modified bricks.

This is helpful when you want to create texture and depth on a façade with the bricks being placed on different spacing.

A quick note: the technique of using a jumper plate to change the spacing of a brick is also known as AZMEP which is a German acronym for “half stud offset”.

Angled placement of bricks

One legal way of placing bricks at an angle without using hinges is to use the Pythagorean Triangle theorem as the basis for the spacing of the studs.

Using the spacing of a 3-4-5 stud triangle allows you to place a 6-stud brick at a 30-degree or 60-degree angle in proper spacing without putting the bricks under strain.

This technique is helpful in creating angles, corners, and curves in your design without breaking any LEGO® building rules.

To better understand the technique, you can check out the below YouTube video (656 seconds in).

Learning from other Designers/Creators

An effective way to learn new techniques is to read and watch other designers & creators.

There may be techniques that can be applied in your planned design that someone has already thought of, just be careful to not copy their work, this is just for inspiration. 

LEGO is also about sharing ideas and most designers are happy to share their techniques so if you have a question reach out and ask them.

There are lots of blogs & videos on YouTube showing different styles and techniques that other creators have done. Learning from their posts would greatly increase your knowledge of building MOCs.

Building MOCs by other Designers/Creators

Getting your hands on a LEGO® MOC where building instructions have already been done for you is another great way to learn techniques for building, designing, and publishing your MOCs.

When you buy building instructions for a LEGO® MOC, you will typically receive two or three files:

  • Digital building instructions in PDF version
  • Parts list in XML and/or PDF version
  • Design file (for Stud.IO or LDD)

You may or may not get access to the design file though as some designers are not willing to share it. This is normally for copyright reasons.

If you are looking to buy a LEGO® MOC to import it into software like, you may need to check with the designer if the .IO file is included in the downloadable files.

One other benefit of building another designer’s LEGO® MOC is that it lets you get used to using Bricklink to create a wanted list that will allow you to buy bricks for your projects.

There is a guide here that you can take a look at to guide you in uploading the parts list to

In the early days, one benefit of buying your bricks from Bricklink is that it will help you build your knowledge about the different LEGO® pieces available and the dynamics of the website, this will help when trying to design your own MOC.

Belle-Ve Bricks have thousands of LEGO® MOCs available in the shop. you should take a look at what’s available today.

Communicate and collaborate with other LEGO® fans/designers

Sharing information is another key to improving your skills in designing and building MOCs.

There are LEGO® groups from different social media platforms that help disseminate information to/from other designers.

You may ask questions and more often than not, people are generous with answering these queries.

Check out our Facebook page and group below:

Build Build Build

There is no hidden trick for this one. Keep building. Apply what you learn from your experience and from others.

Keep learning and trying out new pieces and new techniques. Slowly but surely, you will improve your MOC designing and building skills.

How do I design and build my first LEGO® MOC?

There are several different types of LEGO® MOCs you can pick from, your decision really depends on your interests, hobbies, and the LEGO® genres you follow.

Don’t overthink it though, start small and work from there.

  1. Choose whether you want to modify an existing set, create your own design or do an alternate build.
  2. Choose whether to build with actual bricks only or design digitally first using software.
  3. Choose what theme you want to create – modular building. Star Wars? Harry Potter? Vehicles?
  4. Choose a certain size or scale you intend for the build
  5. Choose a certain LEGO® element or style that you want to use as the main feature of your design.
  6. In a digital or actual build, start with a fixed section or area of the build. A fixed section is the part that cannot be or is hard to adjust once the design is complete.

    As an example, for a modular building, it’s usually the stairs. Once you have established the position of the stairs, you may design your floor space where it would be easier to adjust the position of furniture, doors, windows, etc.

  1. Continue to design and build while also checking if there are clashes or unstable structures. Adjust when needed. If possible, also try to build portions of the design to scale and check for any issues that the software might not be able to capture.
  2. Continue to improve and optimize the design. Check for any unavailable pieces or colors of a certain piece as well as the prices of some expensive pieces.
  3. Do not forget to save the file as often as possible.
  4. Once the design is complete, generate the XML parts list by uploading the .IO file to
  5. If the purpose of the MOC is for selling on online platforms like Belle-Ve Bricks, generate the instructions as PDF and upload them along with the parts list.

It can be daunting to set out to build your own MOC without any instructions but there are so many resources available online that it is not as scary as you may think.

All in all, never forget making your LEGO® MOC is all about having fun and making something that you can be proud of.

I have mastered building LEGO® MOCs, what now?

There are a few options you can take as “next steps” once you get familiar with the software and have designed a good amount of LEGO® MOCs (successfully that is).

Share your work on social media

There is a huge LEGO® community on social media, especially when it comes to LEGO® MOCs.

This is not a mandatory step to do but you may find that you enjoy sharing your MOCs with like-minded people to see what they think of your work! It is also a great way to get feedback from fellow designers and improve your work.

If you are interested in this, it is advisable to use Flickr, Instagram, and Facebook as the primary social media networks. Click these links if you would like to see our Instagram or Facebook pages to see what sort of MOCs are posted. 

Submit to LEGO® IDEAS

Create a LEGO® MOC and submit it to LEGO® IDEAS. The aim is for your MOC to become an official LEGO® set available for the general public to buy!

More information on this can be found here.

LEGO IDEAS – Submit a Product Idea

Commission work

This is something we do at Belle-Ve Bricks and we know that there are many others out there who do too.

If you have reached a point where you are good at building LEGO® MOCs and you are constantly receiving positive feedback from your followers on social media about your work then this is something you can venture into.

Commission work is when someone wants a custom, unique LEGO® MOC made but they do not have the skills to design it themselves so they come to people like you who can help.

You will estimate the length of time it will take to build the commission for the customer and provide a quote, they are paying for your time to design something you otherwise perhaps would have never designed out of your choosing.

Keep dreaming big

Don’t let this one come away from you, LEGO® is meant to be fun and for 99% of the people that will read this LEGO® will not be their primary job so don’t treat it like one.

Our motto at Belle-Ve Bricks has always been “The Only Limitation Is Your Imagination” and we would encourage you to live by this too.

Have fun, build what you enjoy, and look for new ways that you can challenge your mind to come up with your next LEGO® MOC masterpiece!


If you love LEGO® and want to get those creative juices flowing then creating your own LEGO® MOC is really something I think you should do. 

If you invest the time to try out new techniques to build something that you love, you will soon find your own style that will make you proud to say “Hey, Did you know? That LEGO® MOC was made by me!”.

I hope this post has helped give you a good understanding of LEGO® MOCs and how to get started on your path to LEGO® MOCdom!

Happy building and thanks for reading.

We would love to hear what you thought about this post, drop a comment below to share your thoughts. If you think others would enjoy it why not share it on social media too

Further Reading

Now you have got stuck into the detail of LEGO® MOCs you are ready to start designing your first MOC!

The below posts will give you a good outline to create your very own LEGO® MOC BrickHeadz!


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