What Is a Slicer and How Do You Pick One for 3D Printing, CNC, or Laser Cutting?
A slicer is the software step that turns a 3D model or 2D image into machine instructions: per-layer paths for an FDM printer, exposure images for an SLA printer, or toolpaths for a CNC mill or laser cutter. Pick one by matching it to your machine type first, then to how you want to run it — installed on a desktop, or in a browser with no install and no account. Grid.Space's Kiri:Moto, for example, is a browser-based toolbox that handles 3D printing, CNC milling, and laser cutting, and runs entirely on your device with no cloud dependency.
What a slicer actually does
The name comes from FDM printing, where a solid model is cut into horizontal layers. The same job applies elsewhere:
- FDM: converts a mesh into per-layer extrusion paths, plus supports, infill, and travel moves.
- SLA: produces per-layer exposure images for a resin printer.
- CNC: generates toolpaths (roughing, finishing, drilling) from a model, with feeds, speeds, and stepover.
- Laser: converts 2D artwork or a sliced model into cut and engrave paths, including stacking for multiple passes.
In every case the output is a machine-readable file — G-code for FDM/CNC, a job file for laser, a layer archive for SLA — that the machine or its control software executes.
Match the slicer to the machine, not the other way around
The most common mistake is choosing a tool because it is popular, then discovering it does not support your process. Use the same dimensions when comparing options:
| Dimension | What to check |
|---|---|
| Machine types | FDM, SLA, CNC, laser — does it cover yours? |
| Input | 3D mesh, 2D image, or parametric model |
| Preview | Layer-by-layer visualization before export |
| Repair | Mesh repair, boolean operations, void filling |
| Export | G-code, layer images, laser job formats |
| Where it runs | Desktop install, browser, or cloud |
| Accounts | Required or not |
| Cost | Free, paid, or open-source |
Kiri:Moto covers FDM/SLA printing, CNC toolpath generation, and laser cutting in one tool, and includes simple mesh editing and repair plus parametric CAD modeling. That breadth is unusual — most slicers specialize in one process.
Browser-based vs desktop vs cloud
This choice affects privacy, portability, and offline use more than print quality.
- Desktop install: full local control, but tied to one machine and needs updates and disk space.
- Cloud service: convenient from any device, but your models leave your computer and you usually need an account.
- Browser-based local: runs in the browser sandbox on your own device. Kiri:Moto states that all slicing and toolpath generation happen locally, with no installs, no accounts, and no cloud dependency, and that it works even offline.
Browser-local is the middle path: nothing to install, nothing uploaded. The trade-off is that performance depends on your device and browser rather than a dedicated workstation.
A practical first run
- Import a 3D model or 2D image.
- Choose the process — FDM, SLA, CNC, or laser — since this changes every downstream setting.
- Set machine and material parameters: nozzle or tool diameter, layer height or stepover, speeds, and temperatures where relevant.
- Slice or generate toolpaths, then preview layer by layer or path by path.
- Fix what the preview shows — add supports, reorient the part, or repair the mesh.
- Export the machine file and send it to the machine.
The preview is the verification step. If the preview looks wrong, the machine output will be wrong.
Common failure points
- Non-manifold or broken mesh: the slicer cannot decide what is inside or outside. Repair or boolean-fix the model first.
- Wrong scale: models often import in millimeters when authored in inches, or vice versa. Check dimensions against the real part.
- Missing or misplaced supports: overhangs fail without them; auto-supports sometimes need manual edits.
- Path anomalies in CNC or laser: wrong tool diameter, stepover, or feed settings produce gouges, burns, or broken bits.
- Machine rejects the file: usually a format or firmware mismatch — confirm the export format your controller expects.
Who should consider a browser slicer
If you work across a Chromebook, a shared computer, or several devices, a browser-based local slicer avoids installs and account juggling. Kiri:Moto has been in continuous development for over a decade, is fully open-source and free to use, and is aimed at makers, educators, and prosumers. If you need vendor-specific profiles, tight integration with one printer ecosystem, or heavy simulation, a dedicated desktop slicer may fit better. The deciding question is simple: does the tool support your machine type and let you verify the output before you commit material?