Guides

How to make building instructions for your MOC

Instructions turn a model into something other people can build. They also help you rebuild your own MOC after it comes apart. Here is what makes them easy to follow, and the tools builders use to make them.

What good instructions do

• A few parts per step, close together, so there is one place to look.
• A parts box for each step, showing exactly which pieces to pick up.
• Subassemblies shown separately, then attached, for parts that are easier to build on their own, like a wing or a bumper.
• A clear view: every new part visible, and an arrow or a rotation icon when the model turns.
• No floating parts: every part lands on something already built.
• A full parts list at the start or end.

These match what research on assembly instructions found (Agrawala et al., SIGGRAPH 2003): group related parts, keep new parts visible and give enough context to see where they go.

Tools

• BrickLink Studio’s Instruction Maker is what most designers use. It splits the model into steps automatically, then lets you rearrange steps, add callouts for subassemblies, lay out pages and export a PDF. Expect to spend most of your time fixing the step order and camera angles by hand.
• LPub3D, free and open source, makes instructions from LDraw files you build in LeoCAD or LDCad.
• MOCsmith plans the step order for you from an LDraw file (.ldr or .mpd), which you can export from Studio, LeoCAD or LDCad. On 36 test models it planned steps with no floating parts and at most six parts each, grouped hanging parts into subassemblies and picked a camera view for each step. It makes a PDF book, and it is a quick way to get a first draft to check.

Planning steps one layer at a time from the bottom, which is what a quick automatic split tends to do, leaves parts hanging in mid-air whenever something attaches from above. On our 36 test models that happened in 35. Whatever tool you use, check every step for this.

Test before you share

Build the model from your own instructions with real parts, or ask a friend to. Watch for steps where a part is hidden behind the model, where dark parts disappear against each other, and where the model has to be turned without a hint.

Share or sell them

Rebrickable is where most designers publish MOC instructions. You upload the PDF and the parts list, then choose whether they are free or paid. Builders can then check the design against their own collection. BrickLink’s Studio gallery is another place to share the model file itself.

Make instructions from an LDraw file