Can you achieve the smoothest, most layer-line-free surface finish possible? This challenge pushes your printer tuning, slicer settings, and material knowledge to the limit. The goal is simple but difficult: create a 25mm cube with 2 walls and no top that looks so smooth, people question whether it was actually 3D printed!

This challenge focuses on:

Surface finish quality and smoothness
Proper printer calibration and tuning
Optimal slicer settings for layer adhesion
Material selection and temperature control
The art of making layer lines disappear

Challenge Rules

Materials & Constraints

Filament: 3D Fuel filament (any type: PLA+, Pro PLA+, PCTG etc.)
Nozzle Requirement: Must use a 0.4mm nozzle (REQUIRED)
Estimated Filament Usage: Approximately 3 grams (for reference only)
Model Specification:
- Dimensions: Exactly 25mm × 25mm × 25mm cube (REQUIRED)
- Wall Count: Exactly 2 walls (no more, no less) (REQUIRED)
- Top Layers: 0 (no top surface)
- Bottom Layers: Standard (as needed for proper adhesion)
- Infill: 0% (hollow interior)
Print Mode: Standard FDM/FFF printing (no resin printing)

Competition Categories

Smoothest Surface: Best overall surface finish with minimal visible layer lines straight off the printer
No post-processing allowed - cubes must be judged as-printed

Judging Criteria

Layer Line Visibility (100%): The appearance and visibility of layer lines - less visible is better
- All cubes must meet basic challenge requirements (25mm cube dimensions, exactly 2 walls, no post-processing)
- Winner is determined solely by smoothness of surface and minimal layer line appearance
- Tiebreaker: If two prints are too close to differentiate, the fastest print time wins

Submission Requirements

Physical Model: Bring your printed 25mm cube to the December meetup for judging
Dimension Verification: Must be exactly 25mm x 25mm x 25mm
Wall Count Verification: Must show exactly 2 walls when inspected
Print Time: Record and report your total print time (used as tiebreaker if needed)
Documentation: Include photos showing:
- Close-up surface details
- Overall cube appearance
- Cross-section or wall thickness (optional)
Settings Documentation: Share your winning settings:
- Layer height
- Print temperature
- Print speed
- Cooling settings
- Any special techniques used
Process Notes: Brief description of your approach

Evaluation Process

Dimension & Wall Check: Verification of 25mm cube dimensions and exactly 2 walls (must pass to be eligible)
Visual Inspection: Expert panel examines layer line visibility under good lighting
Community Voting: People's choice for most impressive result

Prizes & Recognition

Awards

Smoothest Surface Winner: Best layer-line elimination straight off the printer
People's Choice Award: Community favorite

Documentation

Winner photos for social media sharing
Settings profiles shared with community
Technique documentation for learning

Timeline

Challenge Announcement: November 12, 2025 (at November meetup)
Submission Deadline: December 10, 2025 (at December meetup)
Judging Period: December 10, 2025 (during December meetup)
Winner Announcement: December 10, 2025 (end of December meetup)

Model Creation Instructions

Using the Provided Model

Download the pre-configured cube:

File Location: Challenge Files/November2025/Cube.3mf
Pre-configured: Already set to 25mm × 25mm × 25mm with 2 walls and no top
Ready to slice: Import into your slicer and adjust settings for your printer

Creating the Cube Model from Scratch

Using Bambu Studio

Step 1: Add Primitive

Open Bambu Studio to a new project
Right-click on the build plate
Select "Add Primitive"
Select "Cube"

Step 2: Resize the Cube

Click to resize the cube
Set X to 25mm and Y and Z should also set to 25mm(If uniform scale cause issue you can uncheck)

Alternative Methods

Fusion 360: Create square sketch (25mm × 25mm), extrude to 25mm height
Tinkercad: Use cube shape, adjust dimensions to 25mm × 25mm × 25mm
FreeCAD: Create cube with specified dimensions
Any CAD Software: Simple cube 25mm × 25mm × 25mm
Use provided file: Open Challenge Files/November2025/Cube.3mf directly

Basic Cube Setup

Slicer Configuration

Create or Download Model:
- Use the provided Challenge Files/November2025/Cube.3mf file
- Or create using any CAD software (25mm × 25mm × 25mm cube)
- Or use the Bambu Studio/Orca Slicer primitive steps above
Slicer Settings (Critical):
- Dimensions: 25mm × 25mm × 25mm
- Wall Count/Perimeters: 2
- Top Layers: 0
- Bottom Layers: 3-5 (as needed)
- Infill: 0%
- Layer Height: Your choice (hint: smaller = smoother, but slower)
Tips for Success:
- Lower layer heights (0.1mm-0.12mm) help reduce visible lines
- Slower speeds improve surface quality
- Temperature tuning is critical for layer adhesion
- Linear advance/pressure advance can help with consistency
- Proper cooling prevents warping without sacrificing layer bonding
- Material choice matters - some filaments naturally produce smoother surfaces

Advanced Techniques to Consider

Slicer Tricks:
- Adjust line width for better wall fusion
- Experiment with different seam positions
- Use variable layer heights if supported
- Try different acceleration/jerk settings
Material Selection:
- Experiment with different 3D Fuel filament types
- Colors can also give different appearance levels

What NOT to Do

Do not exceed 2 walls
Do not add a top surface
Do not deviate from 25mm cube dimensions
No post-processing allowed (no sanding, heat treatment, chemical smoothing, etc.)

Good luck creating the smoothest cube possible! May your layer lines vanish into nothingness!

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November 2025 Challenge: "Wait, This Was Printed? How Are There No Layer Lines?"

Challenge Overview