OpenCube – Modular marble run system

OpenCube – Modular Marble Run System

Build endless marble run layouts by combining modular 44 mm cubes.

OpenCube is a modular marble run construction system designed from scratch for 3D printing. Combine different cube types to create surface tracks, hidden tunnels, level transitions and multi-level layouts.

✨ Features

• Modular 44 mm cube-based construction system

• Same-level routes and multi-level transitions

• Surface tracks and hidden tunnels

• Integrated magnetic alignment system

• Optimized for support-free 3D printing

• Open and expandable design

📦 Suggested Sets

Starter Set

• 2 × Base Cubes

• 6 × Track Cubes (T1, T2, T2, T3, T4, T5)

• 7 × Drop Cubes (D1, D2, D3, D4, D4, D5, D6)

• 1 × Start Cube

• 1 × Finish Cube

• 1 x 16mm marbles

Total: 17 cubes

📂 Cube Categories

Base

Cubes without paths.

Used as foundations and supports for taller constructions.

Track

Cubes that keep the marble on the same level.

A cube belongs to the Track category when the marble enters and exits at the same elevation.

Drop

Cubes that change the marble's elevation.

Drop cubes use sloped channels and tunnels to move the marble between levels.

Start & Finish

Cubes used to begin and end a marble run.

These elements define the starting point and destination of the track.

🧲 Magnetic Alignment System

OpenCube cubes include integrated pockets for 6 × 2 mm neodymium magnets.

For reliable operation and maximum stability, I strongly recommend installing magnets in all cubes.

Magnets improve:

• Vertical stability

• Cube alignment

To install magnets:

1. Add a pause at the appropriate layer in your slicer.

2. Insert the magnets.

3. Resume printing.

⚠ Ensure magnet polarity remains consistent throughout the entire system.

🖨 Recommended Print Settings

Material: PLA

Infill: 5%

Supports: Not required

OrcaSlicer Recommendations

The models shown in the photos were printed using the following settings:

• Adaptive Layers: 40

• Smoothing: 5

• Mouse Ear Brim: Enabled

Adaptive Layers and Smoothing improve curved tunnels, level transitions and reduce stair-stepping on sloped surfaces.

Mouse Ear Brim helps preserve bottom-face geometry, prevents corner lifting and ensures accurate cube alignment.

📐 Model Orientation

All models are already provided in the correct printing orientation.

✔ Rotation around the vertical axis is acceptable.

❌ Do not place another face on the build plate.

Changing the orientation may affect cube functionality and prevent magnet installation.