A print’s surface is decided long before it leaves the printer. Some finishes come from the build plate, some from the slicer, some from the model, some from the spool, and some from your hands afterwards. This note is a map of them, with starting settings, so you can choose a finish on purpose instead of accepting the default layer lines.
1. From the build plate
The face that touches the bed copies the bed. A smooth PEI or glass plate gives a glossy, flat face; a textured PEI plate gives a fine, even grain that hides small flaws and fingerprints. Some makers set fuzzy skin to match their textured plate, so the sides and the bottom of a part look like the same material.
Use it for: flat parts printed face down, such as plates, tags, cards and panels. Put the side people will see on the bed.
2. Fuzzy skin
The slicer makes the nozzle jitter randomly as it prints the outer wall, which gives the sides a matte, felt-like texture and hides layer lines and seams. Two settings control it:
- Point distance: how often the nozzle jitters. Smaller = denser, finer fuzz.
- Thickness: how far it moves each time. Larger = deeper, rougher texture. Keep it below your wall thickness.
A gentle start on a 0.4 mm nozzle is around 0.2 mm thickness with 0.5 mm point distance; many makers like equal values for both. You can apply it to the outer walls only or to the top too, per object with modifiers, or paint it only where you want it. OrcaSlicer also offers different noise types (classic, Perlin, Voronoi and others) for textures that are less uniform.
Use it for: grips, organic objects, and anything where layer lines would look cheap. It makes the print slower and slightly less precise on the outside.
3. Ironing
After the last top layer, the nozzle passes again over the same surface at the same height, extruding very little plastic, to flatten the lines. Starting points: ironing flow around 10% (a little more for PETG), line spacing around 0.1 mm, speed 15–30 mm/s, on the topmost surface only. Set the top layers to a monotonic pattern first, and calibrate flow: a good top surface needs less ironing.
Use it for: flat tops, lids, nameplates, faces where text must read cleanly. It only works on flat surfaces and adds time.
4. Exposed infill and top patterns
Remove the top layers and the infill becomes the surface; or keep the top layer and change its pattern. Concentric, Archimedean chords, Hilbert curve and octagram spiral turn a flat face into an ornament with no extra geometry. The phone holder and the travel sculptures of Alchemic Matter use this: a smooth face on the bed, a patterned face on top.
Use it for: thin flat objects with two readable faces. Check the result in the slicer preview: thin patterns need a well-calibrated flow.
5. Texture in the model
When the texture is part of the geometry, the slicer prints it like any other shape: wood grain, stone, knurling, scales, geometric patterns. You can model it in Blender or CAD, use a pattern generator, or apply a displacement map to an existing mesh: CNC Kitchen’s free browser tool BumpMesh does exactly this, with masking to keep the bottom face flat.
Displacements of a few tenths of a millimetre read well on FDM prints; finer layers capture finer texture. Keep downward-facing surfaces smooth so the part still sticks to the bed and overhangs stay printable.
Use it for: designed textures that must be the same on every print, and functional grip.
6. Layer height as a finish
Layer lines are a texture too. Thin layers (0.08–0.12 mm) make curved surfaces smooth; thick ones make them visibly ribbed. Variable layer height gives thin layers only where the shape curves, and keeps the rest fast. Sometimes the right answer is to keep thick lines and make them part of the design.
7. From the spool
- Matte filaments hide layer lines and look like stone or ceramic.
- Silk filaments shine and show every layer as a band of light: good for flowing shapes, not for precise parts.
- Wood, marble and glitter filaments carry particles; some need a hardened nozzle.
- Translucent filaments show the infill and walls inside: see the transparency note.
8. After the printer
- Sanding with progressively finer grit, wet for the last steps.
- Filler primer and paint, for a surface with no trace of layers.
- Clear coats and resin, for gloss and protection.
- Vapour smoothing for ABS and ASA (with acetone) and some other materials, with proper ventilation and care.
- Heat: a quick pass with a heat gun removes stringing and can gloss PLA, but it softens fine details.
Choosing a finish
| You want | Try |
|---|---|
| Hide layer lines on the sides | Fuzzy skin, matte filament, texture in the model |
| A perfect flat top | Monotonic top layers, then ironing |
| A decorated flat object | Bed face down, patterned top layer or exposed infill |
| Grip | Fuzzy skin or a modelled knurl |
| A material look | Displacement texture plus a matte or wood filament |
| No trace of printing | Sanding, filler primer and paint |