Atomizer: Beyond Non-Planar Slicing for Fused Filament Fabrication

This repository contains the implementation of Atomizer, a novel toolpath generation algorithm for fused filament fabrication (FFF) 3D printing. Atomizer introduces the concept of atoms as a replacement for traditional slices. This method enables collision-free toolpaths that tightly conform to complex geometries and offer new fabrication capabilities.

• Project page
• Article (preprint)
• Supplemental Video

Xavier Chermain, Giovanni Cocco, Cédric Zanni, Eric Garner, Pierre-Alexandre Hugron, and Sylvain Lefebvre

Université de Lorraine, CNRS, Inria, Loria

Computer Graphics Forum (Proceedings of the Symposium on Geometry Processing), 2025

SGP Honorable Mention

Key Features

• Toolpath generation using frames (i.e., atoms) instead of slices
• Control of the deposition direction and tool orientation
• Collision-free toolpath ordering
• Support for anisotropic appearance on curved surfaces

Replicating One Result (for the Impatient)

This set of PowerShell commands reproduces the colored mesh of Fig. 17 (top left) from the article. You’ll need Windows 10 or newer and Blender to visualize it.

Open PowerShell as Administrator, then run:

.\install_git_blender_miniconda.ps1

Close and reopen PowerShell. Then run:

git clone https://github.com/xavierchermain/atomizer
cd atomizer
conda create --name atomizer python=3.10
conda activate atomizer
pip install -e .
python tools/atomize.py data/param/tubes.json
python tools/toolpath_to_ply.py data/toolpath/tubes_smoothed.npz data/mesh/tubes.ply
blender --python see_toolpath_with_blender.py -- "data/mesh/tubes.ply"

Notes

• The script install_git_blender_miniconda.ps1 sets up Git, Blender, and Miniconda if needed.
• pip install -e . installs the repo in editable mode inside the atomizer conda env
• If blender isn’t on your PATH, use the full path to blender.exe.
• If something goes wrong, please read the following.

Installation

The code compiles, runs, and is maintained on Windows 10 or newer. It has also been tested on Linux and macOS, but we do not provide installation guidance for those platforms. The following installation instructions target Windows 10 or newer.

Dependencies

To install the dependencies (Git, Blender, and Miniconda), we provide a script that automatically downloads and installs all of them:

.\install_git_blender_miniconda.ps1

The script checks whether the softwares are already installed; if not, it installs them and adds them to the PATH. Alternatively, you can install them manually by following the instructions on the respective software websites.

• Blender must be installed and added to your executable path. It is used to remesh the model (see tools/process_for_atomizer.py) for the atomizer. We tested with Blender 4.4 and 4.5.
• Git and Miniconda are optional dependencies if you are already comfortable with code cloning, Python environments, and modules.

Clone the Repository

git clone https://github.com/xavierchermain/atomizer

Install Python and Module Dependencies

This implementation is written in Python 3.10. Supported versions are Python >= 3.7 and < 3.11, as required by the Taichi module dependency. The implementation also relies on the local library src/atom. Please refer to pyproject.toml for the complete list of Python module dependencies.

Conda

We recommend using Miniconda to install a specific version of Python, the dependencies, and the local library src/atom:

conda create --name atomizer python=3.10
conda activate atomizer
pip install -e .

Usage

Atomize

python tools/atomize.py data/param/<json_filename>.json

The parameters in the JSON file are:

• solid_name: the filename of the STL representing the 3D solid, without the extension. The STL file must be located in the data/mesh/ folder and have the .stl extension.
• deposition_width: the deposition width in millimeters. The layer height is half the deposition width in our implementation.
• max_slope: the maximum tilting angle of the tool, in degrees.
• top_lines and bottom_lines (optional): paths to single-channel, 8-bit-per-pixel PNG files representing the target tangent directions for the top and bottom surfaces, respectively. The mapping is $[0, 255] \leftarrow [−\pi/2, \pi/2]$. The orientation defines a 2D line in the xy-plane. The 2D line field is defined on the upper face of the solid’s bounding box and is planarly projected onto the top and bottom surfaces along the z-axis.
• ortho_to_wall (optional): if true, forces the tool orientation to be parallel to the boundary. By default, this is false, as enabling this feature causes many tool orientation changes that are detrimental to surface quality.

The inputs and outputs are:

• STL input: data/mesh/<json_filename>.stl
• Toolpath output: data/toolpath/<json_filename>.npz
• Log file: data/log/<json_filename>.log

Refer to the log file to see all the individual computation and visualization commands.

Add the --warmup option to exclude the compilation time from the computation time reported in the log file. Caution: this causes each step of the pipeline to run twice, as Taichi uses just-in-time compilation.

Example

python tools/atomize.py data/param/tubes.json

Visualize

After using the atomizer, you can visualize the generated <toolpath> with:

python tools/visualize_toolpath.py data/toolpath/<toolpath>.npz

Use the WASD keys and the right mouse button to move the camera. Press H to hide the travel paths.

Check the log file generated by the atomizer tool to see all individual visualization commands.

Example

python tools/visualize_toolpath.py data/toolpath/tubes_smoothed.npz

Export Toolpath Mesh

python tools/toolpath_to_ply.py data/toolpath/<toolpath>.npz data/mesh/<toolpath>.ply

The generated mesh <toolpath>.ply can be visualized in Blender.

blender --python see_toolpath_with_blender.py -- "data/mesh/<toolpath>.ply"

The script displays the toolpath relative length using the Turbo colormap.

To do it manually, you need to add a material to the mesh. Then, in the Material tab, do the following:

1. Select Base Color.
2. Choose Color Attribute.

To visualize the vertex color attribute:

1. Select Shading (shortcut z).
2. Choose Material Preview (shortcut 2).

Example

python tools/toolpath_to_ply.py data/toolpath/tubes_smoothed.npz data/mesh/tubes.ply
blender --python see_toolpath_with_blender.py -- "data/mesh/tubes.ply"

Commands Manuals

Tool manuals are accessible by typing --help, e.g.,

python tools/atomize.py --help

Repository Structure

atomizer/
├── tools/                             # The main tools
│    │── atomize.py                    # Main pipeline entry point
│    │── bpn_to_sdf.py                 # SDF generation and voxelization
│    │── compute_tool_orientations.py  # Tool orientation field optimization
│    │── compute_tangents.py           # Deposition tangent field optimization
│    │── align_atoms.py                # Tricosine field optimization
│    │── extract_explicit_atoms.py     # Atom extraction
│    │── order_atoms.py                # Atom ordering
│    │── visualize_bpn_sdf.py          # Visualize SDF
│    │── visualize_bpn_df.py           # Visualize tool orientation field
│    │── visualize_bases.py            # Visualize deposition tangent field
│    │── visualize_implicit_atoms.py   # Visualize tricosine field
│    │── visualize_explicit_atoms.py   # Visualize explicit atoms
│    │── visualize_toolpath.py         # Visualize generated toolpath
│    └── ...                           # Other tools
│── data/                              # Input and output data
│    │── mesh/                         # Input STLs
│    │── param/                        # Input parameter JSON files
│    │── toolpath/                     # Output toolpaths
│    └── ...                           # Other data
├── src/atom/                          # Local library with core functionalities
├── experiment/                        # For experimenting with core functionalities
├── generate_results.ps1               # Script to generate toolpaths
└── README.md

3D Printer

Atomizer was tested on a custom 3-axis printer with independently controlled Z-axis screws. The customization is intended for experts; consequently, we do not provide any GCODE to prevent users from damaging their machines. The code generates only the sequence of positions, each associated with a tool orientation and a travel type (deposition or no deposition). The generated toolpaths are available in data/toolpath. To print, you must use the inverse kinematics model of your machine.

Citation

If you use this code in your research, please cite:

@article{Chermain2025Atomizer,
author = {Chermain, Xavier and Cocco, Giovanni and Zanni, Cédric and Garner, Eric and Hugron, Pierre-Alexandre and Lefebvre, Sylvain},
title = {{Atomizer: Beyond Non-Planar Slicing for Fused Filament Fabrication}},
journal = {Computer Graphics Forum (Proceedings of the Symposium on Geometry Processing)},
year = {2025},
doi = {https://doi.org/10.1111/cgf.70189},
}

License

The source code is under the BSD 3-Clause "New" or "Rivised" license. See LICENSE for more details.