Pick a flat face or a cylinder on a model and make part or all of it open-cell gyroid, for printing fillable carbon filters. The gyroid replaces the solid wall, so air can pass through while the carbon granules stay inside.
It works with Cura, PrusaSlicer and OrcaSlicer:
| Slicer | How you use it |
|---|---|
| Cura | A plug-in adds a Gyroid Filter tool. Select the model, pick the tool, click a face or cylinder. |
| PrusaSlicer | Pick in the app, press PrusaSlicer 3MF, open the file. The open-cell regions are already there as modifiers. |
| OrcaSlicer | Same, with OrcaSlicer 3MF (see what is tested). |
PrusaSlicer and OrcaSlicer have no plug-in system that can pick faces, so for them the companion app does the picking and hands the slicer a normal 3MF. Your original model is never changed.
Quick start (no terminal needed)
- Unzip, and double-click the launcher for your computer:
- Linux:
GyroidFilter-Linux.sh(choose Run or Run in Terminal) - Windows:
GyroidFilter-Windows.bat - Mac:
GyroidFilter-Mac.command(first time: right-click, then Open, because it is unsigned)
- Linux:
- Your browser opens. Press Load example cartridge (or open your own STL/3MF).
- Click a face or a cylinder on the model. The picked surface turns orange; a yellow preview shows the region that will become open-cell.
- Press Add open-cell region. Repeat for other surfaces.
- Press PrusaSlicer 3MF, OrcaSlicer 3MF or Region STLs, and open the file in your slicer. For Cura see below.
Needs Python 3.8 or newer (nothing else; no packages to install). The launcher says what to do if Python is missing.
What the options mean
| Option | What it does |
|---|---|
| Open all the way through the wall (default) | Measures the wall thickness under the picked surface and makes the region that deep, plus 0.3 mm so it breaks through. For a filter wall this is what lets air cross. Untick to choose a depth. |
| Gyroid density (5–60 %) | The slicer's infill density inside the region. Lower means bigger pores. How big the pores are for a given density is not measured yet: print a small test piece with your nozzle and your carbon before you commit. |
| Solid rim (mm) | Leaves a solid frame around the open area (for a cylinder: at both ends) so the part keeps its strength and has somewhere to glue or seal. 0 = the whole surface. |
| Only part of it | Limits the region to a window on a flat face (rectangle or oval, in % of the face), or to a stretch along and around a cylinder. |
"Open-cell" here means the region is printed with no walls, no top or bottom skin and no "small area becomes solid" rule, so the gyroid strands are the surface.
The settings it applies
| Cura (cutting mesh) | PrusaSlicer (modifier) | OrcaSlicer (modifier) | |
|---|---|---|---|
| Pattern |
infill_pattern = gyroid |
fill_pattern = gyroid |
sparse_infill_pattern = gyroid |
| Density | infill_sparse_density |
fill_density |
sparse_infill_density |
| Walls |
wall_line_count = 0 |
perimeters = 0 |
wall_loops = 0 |
| Top/bottom skin |
top_layers, bottom_layers = 0 |
top_solid_layers, bottom_solid_layers, *_solid_min_thickness = 0 |
top_shell_layers, bottom_shell_layers, *_shell_thickness = 0 |
| Small areas |
min_infill_area = 0 |
solid_infill_below_area = 0 |
minimum_sparse_infill_area = 0 |
If a 3MF does not do what you want in your slicer, you can do the same by hand: add the Region STLs as modifiers and set these five things.
Cura
- In the app open the Cura plug-in tab, press Install next to your Cura version, restart Cura.
- In Cura: select your model, choose the Gyroid Filter tool in the left toolbar, and click a face or cylinder.
- The region appears as a child of the model (a cutting mesh carrying the settings above). Slice, then look at the layer view.
- Change density or rim in the tool panel and press Re-apply to last pick; Remove gyroid regions clears them.
Cura's log (cura.log) gets a line GyroidFilter: core self-test PASS when the plug-in loads; the Cura tab in the app reads it and shows a green tick.
What is tested, and what is not
| Part | Status |
|---|---|
| Face and cylinder detection, region solids, thickness probe | ✅ unit tests on the example cartridge, boxes, a half-pipe and a finely tessellated cylinder |
| PrusaSlicer 3MF | ✅ sliced in a real PrusaSlicer 2.7.2: inside the region only gyroid-style infill, no perimeters; above the rim normal walls; flat oval window in a plate also checked |
| OrcaSlicer 3MF | ⚠️ not opened in Orca yet. Written to Orca's own layout by reading Orca's importer source and its setting names. If it misbehaves, use the Region STLs route |
| Cura plug-in | ✅ Tested by the author in a real Cura on Linux Mint: it works well. Also tested against stand-ins for Cura's API, and every Cura setting name is checked against Cura's fdmprinter.def.json. Windows and Mac are not tested yet. Please report what happens on your setup |
| Web app | ✅ driven in headless Chrome (pick, preview, add, export, Cura tab): no JavaScript errors |
| Linux launcher | ✅ run for real. Windows and Mac launchers were not run |
| Printing a filter | ❌ nothing has been printed or filtered with this yet. Pore size versus density is unmeasured |
| 7th-gen Core i3 | ⚠️ not measured on one. On the 2-core test machine a 200,000-triangle model loads and picks in about a second and needs about 200 MB; see DESIGN_NOTES.md |
More
- HOW_IT_WORKS.md: what it reads, changes and never does
- DESIGN_NOTES.md: research notes, decisions, rejected ideas, measurements
- CHANGELOG.md · docs/HISTORY.md · THIRD_PARTY.md · CONTRIBUTING.md · SECURITY.md
Related projects by the same author: flatlock / Shift-LoK (interlocking walls for the same three slicers) and cura-hybrid-supports (another Cura plug-in). This project shares their approach of working inside the slicer's own settings rather than rewriting G-code.
Project started 2026-11-09 09:55. Built by Matthew Armstrong with Claude.
Source code: The-Dorkknight/gyroid-filter on GitHub
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