More Than Meets the Brick

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Have you ever wanted to build a truck that transforms into a robot, a car that converts into a plane, or a Grandfather Clock that can stand up and walk around? What about a wall with a secret staircase or a hidden doorway built into it? The possibilities are endless and creating these types of transforming Lego builds can be a challenging but rewarding experience that combines art and engineering.

In this article, I’m going to go over my thought processes on some of the transforming Lego builds I have made over the years.

Before You Start

There are three points to consider before building a transforming MOC:
  • Purpose: Maybe you like the theme or a specific character, maybe you are looking for an engineering challenge, or a reason all your own.
  • Inspiration: Be clear on what is inspiring you. For one of my builds, I wanted to turn the Santa Fe Super Chief (10020) into a robot.
  • Scale: Dependent on the first two points, the scale of your MOC may be hard set to a specific size. Be aware that things like minifig scale or the size of a specific piece will influence your build.


Once you decide what you want to build, online research allows you to see if/how there are similar MOCs. Some skip this step but I like seeing the techniques of others to help me visualize and find ways to improve upon them.

I use many blogs, YouTubers, and Facebook groups because sometimes they lead me down a totally new and unforeseen path that adds to my inspiration.


Consider how both modes will look and choose the mode you wish to look best or most recognizable, for me it is usually the non-robot mode.

Typically, you have more creative freedom with the robot mode so I start with the alt-mode since it has more specific constraints. Visualizing this will help you decide if the hood of the car should form the feet or the shoulders for example. For my Santa Fe Super Chief, I wanted the front of the locomotive to be the main part of the body. Lastly, keep in mind color choices, as we all know some parts may not be available in the color you want.


While you build keep in mind that it will need to transform and try not to use large parts that will make transformation difficult. If your build is symmetrical you can do just half of it then mirror it at the end.


If you are building something that is going to stand up, use joints and hinges that will provide the articulation you want but gives the MOC the strength it needs. Sometimes having both is not possible, especially for larger builds, so articulation is always sacrificed for stability.


I keep on hand as many joints and hinges as I can find and am always on the lookout for ones I don’t have. Parts like the 1x2 plate with tow ball and socket (14419) work great for smaller scale builds but don’t provide much strength.


For larger builds, parts like the 2x2 brick with ball (57909) work much better. Ratcheted joints like the 2x2 brick with the rotation joint ball half (48171) and the 2x2 brick with rotation joint socket (48169) are some of my favorites because they provide good articulation and strength. The strongest joints I have found are the technic rotation joints (44224) and (44225) but they are difficult to use because of their large size. I try to avoid joints that just use stud friction but they can be useful in small-scale builds.

Failed Attempts


Sometimes you work really hard on a build and for one reason or another it doesn’t work. Don’t worry, failed attempts can help you figure out issues you may not have realized so keep at it. Go back to your research and see how others might have solved the problem.

If the roadblocks persist, take a break from it but don’t take it apart. Time can provide new inspiration, new techniques, heck, even new parts. Sometimes failed attempts can hold answers to new and completely different builds.


My transforming Santa Fe Super Chief, Switchtrack, technically took 3 years to complete. My First attempt was July 2016, the next was September 2017, and the last attempt was late 2018 after I met and spoke about it with another builder at Brickworld. Finally, Switchtrack made its debut at the 2019 Brickworld where it was nominated for best train! Talk about a robot in disguise!!



Something I learned early on is that a build with two modes is at a disadvantage in static displays, it needs to be shown how it changes to those looking at it. Engage people at shows who are interested or build two copies so you can display both modes. How you want to tackle this depends on your circumstance and preference, there is no wrong choice.

The most important thing I’ve learned while building my transforming MOCs is there is always a different technique or part to try. Take inspiration from official Lego builds, other MOCs, anywhere you can because we all learn from each other.


Article and images provided by William Sabo

If you want to see more of William’s transforming builds check out his Flickr and Instagram pages.