PELA blocks are designed for easy 3D printing, strength, and rapid customization using free software. One time calibration gives perfect snap-together objects in exotic materials and geometries to help you explore your ideas and build with exotic materials and any motors and electronics you like. Example enclosures with many options for custom sensors, actuators, computers and IoT devices are included, or create your own.
These designs are not by the LEGO corporation. LEGO-compatible blocks are available from multiple manufacturers. Associated patents expired long ago in a forgotten age.
The name PELA comes from the Finnish “pelataan” meaning “let’s play”. Pelataan.
These open source designs are brought to you by Futurice and contributions from the community. Come work with the best.
The software needed is free and open source, OpenSCAD. You can probably learn it in less than an hour.
The STL files shown are examples only. To get a good snap fit with your 3D print, you need to fine tune the size of top and bottom connectors. It is also easy to personalize PELA designs- start by turning on or off optional features.
git clone email@example.com:LEGO-Prototypes/PELA-parametric-blocks.git --recurse-submodules, then
git lfs installin each git module
See Advanced Setup for additional tricks sparse update to save you space and bandwidth, Raytraced image generation, command line STL cleanup and and batch file generation of all models when you change filaments.
See the Slicer Recommendations for settings recommendations and material information.
To get a perfect LEGO-compatible and technic-compatible fit, do some test fits against a printed calibration block tune 3 numbers before generating the STL model for your plastic and printer.
Print one of the 4 calibration blocks below. Test fit some LEGO on the top and bottom to find the perfect fit. Test fit a technic connector on the side. When you update those material settings in
print-parameters.scad then one time calibration is complete.
PELA Calibration Bar, Normal Filament, Thin Sockets PELA Calibration Bar for normal filament (non-flexible) and a fine extruder (nozzle less than 0.5mm diameter- thin bottom socket walls)
PELA Calibration Bar, Normal Filament, Thick Sockets PELA Calibration Bar for normal filament (non-flexible) and a large extruder (0.5mm diameter or greater, or if you prefer to avoid thin walls)
PELA Calibration Bar, Flexible Filament, Thin Sockets PELA Calibration Bar for flexible filament (TPU etc) and a fine extruder (less than 0.5mm diameter- thin bottom socket walls)
PELA Calibration Bar, Flexible Filament, Thick Sockets PELA Calibration Bar for flexible filament (TPU etc) and a large extruder (0.5mm diameter or geater, or if you prefer to avoid thin walls)
TL;DR : To get a nice snap fit, print
PELA-calibration.stl and test the fit with commercial LEGO. Type the best
print-parameters.scad. Now open any model in OpenSCAD, press
Export as STL.
Your printer, slicer settings, and plastic effect the precise fit. To correct for this, we adjust the models slightly for your printing process. Calibration is a one time process for each material. It is as simple as fitting two blocks together and editing a text file,
print-parameters.scad to indicate which test block fits best.
Before you print the calibration bar, be sure to set the
large_nozzle settings in
After you print the clibration bar, you update three settings to get a tight fit:
axle_hole_tweak. These can be read from the side of the calibration bar.
top_tweak(on the side, near the top) and
bottom_tweak(on the side, near the bottom) values that you can read from the side of the bar into
PELA Blockin OpenSCAD using these new settings, press
F6to render, and
.STL. Windows command line scripts are provided:
.\block.ps1 2 2 1or
.\technic-block.ps1 2 2 1
axle_hole_tweaknumbers change along with
An alternative set of individual calibration blocks are available, and if you have an unusual material there are other numbers you can tune such as various part thicknesses. See Advanced Calibration
parameters.scad to adapt these models before printing them. The example models below are not yet calibrated for your slicer and printer. Calibrate and then make the tuned model from the .scad file.
3D PELA Block with technic connectors Optional vents help to dissipate heat. There are several types you can select from.
3D PELA Socket Panel Insert knobs from both the top and bottom. Zoom in to see the subtle flexure ridges for enhanced “snap” fit.
3D PELA Knob Panel Optional corner holes for M3 bolts can be enabled
3D Double-sided PELA Knob Panel Double sided. Enable print supports in the slicer.
3D PELA Technic Pin This is difficult to print with some material, but useful you run short and don’t want to wait for mail order. It works best with slightly flexible materials.
3D PELA Technic Pin Array A set of technic pins for multi-point connection.
3D PELA Technic Raspberry Pi 3B Mount A Raspberry Pi 2/3 holder.
3D PELA Technic Raspberry Pi 3B Cover A Raspberry Pi 2/3 holder optional top cover.
3D PELA Technic Raspberry Pi 3B Corner An optional Raspberry Pi 2/3 techic corner to help attach the top cover.
3D PELA Technic Pi Camera Mount A Raspberry Pi 3 camera holder.
3D PELA Technic NodeMCU v2 Mount A technic mount for NodeMCU v2.
3D PELA Technic Seeed Respeaker Core v2 Mount A technic mount for the Respeaker Core v2 microphone array.
3D PELA Technic Seeed Respeaker Core v2 Top The opaque part of the lid for the Respeaker Core v2 microphone array. Change “two_color_print=false” in “print-parameters.scad” or two color print this with the “clear ring” part below.
3D PELA Technic Seeed Respeaker Core v2 Clear Ring The clear part of the top lid to for the Respeaker Core v2 microphone array. Part of a two color print with the “top” part above. In a two_color_print, the top board mounts are included in this clear material since some overlap these LED viewports.
3D PELA Technic Bar A minimalist technic bar.
3D PELA Technic Bar A technic bar with a center section of holes rotated 90 degrees.
3D PELA Technic Bar 30 Degree A technic bar at a 30 degree angle from a second technic bar.
3D PELA Technic Bar 45 Degree A technic bar at a 45 degree angle from a second technic bar.
3D PELA Technic Bar 60 Degree A technic bar at a 30 degree angle from a second technic bar.
3D PELA Technic Bar 90 Degree A technic bar at a 90 degree angle from a second technic bar.
3D PELA Technic Bar 120 Degree A technic bar at a 90 degree angle from a second technic bar.
3D PELA Technic Axle Rigid and flexible material shafts of adjustable length for attaching to other 3D printed designs such as wheels which you want to rotate freely.
3D PELA Technic Cross Axle Rigid and flexible material torque drive shafts for adjustable length for attaching to other 3D printed designs.
3D PELA Openbeam 15 Twist Connector Insert into Openbeam 15 aluminum extrusion and twist 90 degrees to lock. This has the advantage over some other connection types that you do not need access to the ends of the beam which may require disassembly.
3D PELA Sign Change the text to label your designs. Options include front and back text with either etched for raised text.
3D PELA Panel Sign Change the text to label your design either edtched for raised text.
3D PELA Intel Compute Stick Box Lid Enclosure cover. You may prefer a knobbed or flat panel, but ensure proper ventilation.
3D PELA Grove Module Attach a Grove module to your build such as a plug-in electronic sensors (ultrasound, touch..) with a 4 wire plug in connector. Snap your design together with no breadboarding and no soldering!
3D PELA N20 Gearmotor Enclosure Add a commonly available small gear motor to your design. Adjust the model parameters to fit other motor sizes.
3D PELA HTC Vive Tracker Screw Use this printable bolt for flush mounting the HTC Vive Tracker (above), or use a standard tripod bolt. The printed version works better than you might expect.
3D PELA Velcro Mount For attaching using Velcro or similar straps through the bottom slot.
3D PELA Velcro Mount For attaching the HTC Vive Tracker or other sensors using Velcro or similar straps. Use this for example to attach position sensors to your shoes.
3D PELA Raspberry Pi 3 Board Mount A base allowing snap-in holding of the board with full connector access and optional top cover
3D PELA PCA9685 16 Channel Servo Board Mount For holding a servo board within a PELA block with connectors exposed at one end
3D PELA NodeMCU-32s Board Mount For holding an NodeMCU-32s microcontroller board within a PELA block
3D PELA NodeMCU v2 Board Mount For holding an NodeMCU v2 microcontroller board within a PELA block
3D PELA Arduino Mega Board Mount For holding an Arduino Mega within a PELA block
Advanced | External Thing Wall Type | Allow single extrusion walls
Creative Commons Attribution-ShareAlike 4.0 International License
These designs are by PELA project contributors, not by the LEGO corporation. They are compatible with LEGO and similar blocks available from multiple manufacturers and online projects. The associated patents have expired. These designs are not identical to LEGO; they have been specially modified for easy 3D printing and offered in the spirit of open source collaborative innovation.
If what you want is available as injection molded plastic, buy it for the higher quality and durability. These model are helpful when you want something customized, a special color, an unusual material, and for replacement parts when you just can’t wait.
The generated 3D models displayed here are hosted in a separate GitHub project to minimize the size of pulling changes in this repo: PELA-parametric-blocks-render
If you don’t find what you need, consider adding it, contact us or check out the many other excellent design available.
Thingiverse Parametric LEGO Group are alternate source of these and other block designs.
New models, collaboration and pull requests are welcome. You have the tools- now create something cool and share with the world : https://github.com/LEGO-compatible-gadgets/PELA-parametric-blocks
If you like what you see, please tweet and let others know!