Bed Adhesion Settings in PrusaSlicer: Skirt, Brim, Raft and Elephant Foot, Explained

If your prints keep peeling, warping or popping off mid-job, the fix is usually buried in three or four settings you’ve scrolled past a hundred times. This guide covers the bed adhesion settings that actually matter — skirt, brim, raft, brim separation gap and elephant foot compensation — with the real numbers, where to find them, and how they interact. We give the values for the ATN Slicer (our free OrcaSlicer-based slicer with the AI print-doctor built in) as the main route, with notes for PrusaSlicer and OrcaSlicer too. No hype, just the dials that keep a part stuck to the plate.

Before we dig in: adhesion is a system. Settings sit on top of a clean, level bed at the right temperature. If your first layer is fundamentally wrong, no brim will save you. If you’re not sure which it is, start with our piece on first layer adhesion checks that actually work, then come back here to tune the slicer side. If you want the settings checked before you even press print, the ATN Slicer flags bad combinations the moment you slice — it’s a free Windows download.

The three adhesion assistants: skirt, brim and raft

Every modern slicer gives you three build-plate adhesion aids, and they sit on a clear scale of “how much help do I need?”:

Skirt — best when you just want to confirm the bed is level and extrusion is flowing. It barely helps adhesion; it primes the nozzle.
Brim — best when you want a meaningful adhesion boost without wasting much filament or fighting a raft off the bottom afterwards.
Raft — for when you want maximum adhesion help, typically on awkward materials or tiny contact patches, at the cost of filament, time and a rougher bottom surface.

Most functional prints never need a raft. Reach for a brim first.

Skirt settings: priming and a free level check

The skirt is a printed outline around all the models on the plate, laid down before any model. Its main job is to stabilise filament flow through the nozzle, but it’s also genuinely useful for verifying first-layer adhesion. Because it prints first, you can watch it and nudge Live Z (or your printer’s baby-stepping) on the fly if the line is too squished or barely sticking.

In the ATN Slicer (and OrcaSlicer, which shares the same setting names and locations), you’ll find these under Others → Skirt. In PrusaSlicer they live under Print Settings → Skirt and brim:

Loops — the number of outlines. Set this to 0 to disable the skirt completely.
Distance from object — how far the skirt sits from the part.
Skirt height (layers) — how many layers tall the skirt is.

One tip carried over from Prusa’s own profiles: a one-layer skirt can be fiddly to peel off the bed, which is why stock profiles often use a three-layer-tall skirt. Also note that if a minimum extrusion length is set, the slicer may print more loops than you configured to hit that priming volume.

Brim settings: where the real adhesion gains are

A brim is a single-layer-tall apron of multiple walls printed around your part, with the final wall connected to the first layer of the model. That extra connected surface area is what holds the part down — it’s the most cost-effective adhesion insurance you can buy.

In the ATN Slicer/OrcaSlicer, set a brim width greater than 0 under Others → Brim (choose a brim type to enable it). In PrusaSlicer, set the brim width under Print Settings → Skirt and brim → Brim.

Brim width — the horizontal width printed around each object on the first layer. The general advice is at least 3 mm to meaningfully help adhesion. Community guidance commonly lands around 5–10 mm for everyday prints, and roughly 8 mm when you want a strong hold on a part that’s prone to lifting.
Brim type — choose Outer brim only, Inner brim only, or Outer and inner brim. Inner brims fill enclosed holes in the footprint, which helps tall parts with internal cavities.
Brim separation gap — the offset between the brim and the object, for easier removal (more on this below).

The ATN Slicer and OrcaSlicer also support per-object brim: right-click an object to override its brim settings independently of the rest of the plate. In PrusaSlicer this lives in Advanced and Expert modes. Handy when one part is a tall, tippy thing and the rest are fine.

Getting the brim separation gap right

The brim separation gap exists to account for first-layer squish and to tune how firmly the brim grips the part. Here’s the catch most guides skip: the gap value is not the literal physical gap. The separation is measured from the line the nozzle follows, so if you squish your first layer harder or softer, the filament spreads differently and the real-world gap shifts with it.

A sensible repeatable starting point is roughly half a nozzle diameter (so around 0.2 mm on a 0.4 mm nozzle), then calibrate from there. Worth knowing: in PrusaSlicer, negative separation — deliberately overlapping the brim into the part for a stronger bond — is not supported in the UI. It’s been requested but isn’t a setting you can dial in there today.

Elephant foot compensation and why it can detach your brim

When the first layer is pressed against the heated bed it squashes out a little wider than designed. Elephant foot compensation (EFC) shrinks the first layer to correct that bulge. In the ATN Slicer/OrcaSlicer find it under Quality → Precision → Elephant foot compensation; in PrusaSlicer it’s under Print Settings → Advanced → Elephant foot compensation (Advanced or Expert mode only).

Recommended value: around 0.2 mm works well for the default 0.4 mm nozzle, and it’s on by default in official profiles.
Thin-line protection: these slicers detect thin first-layer lines and avoid over-shrinking them, so EFC doesn’t gut fine detail.

The critical interaction: EFC weakens the brim’s connection to the model. If your brim prints but won’t actually grip the part, your elephant foot compensation is probably set too high. This used to be a real headache.

The good news — in the ATN Slicer and OrcaSlicer (and in PrusaSlicer since 2.4.0), the brim is generated after EFC, and the brim separation parameter is independent of it. As long as your brim separation is set to zero, EFC should never detach the brim from the object. (One PrusaSlicer quirk: when you open a 3MF saved by an older version, the brim separation is set equal to the old EFC value so the result matches the original.)

A practical recipe

Start with a three-layer skirt to prime and confirm your first layer visually.
For anything taller than it is wide, or any material that lifts, add a 5 mm brim (8 mm for stubborn parts).
Leave EFC at ~0.2 mm and brim separation at 0 for the strongest brim bond; only raise separation if the brim is impossible to remove.
Only escalate to a raft when a brim genuinely can’t hold the contact patch.
Slice in the ATN Slicer and let the built-in pre-flight engine flag anything that’ll fail before you waste filament.

If you’re still chasing peeling and curling after this, it’s often a warping problem rather than pure adhesion — see how to fix warping in 3D prints. For material-specific quirks, our guides on PLA first-layer problems and PETG sticking too well (or not at all) go deeper. And for the full settings rundown beyond adhesion, see our best first layer settings in PrusaSlicer. If you’re slicing in OrcaSlicer instead, we’ve got an OrcaSlicer first layer adhesion settings guide too. Related: still not sure whether your issue is adhesion at all? Our overview of why prints fail and the exact fixes covers the wider picture.

FAQ

How wide should a brim be?

At least 3 mm to meaningfully help adhesion. Most everyday prints do well around 5 mm, and 8 mm is a good choice for tall or warp-prone parts. Wider than that rarely adds much and just wastes filament and removal time. This holds whether you’re in the ATN Slicer, OrcaSlicer or PrusaSlicer.

Why won’t my brim stick to the part?

Two usual culprits: elephant foot compensation set too high (it shrinks the first layer away from the brim), or a brim separation gap above zero. In the ATN Slicer and OrcaSlicer (and PrusaSlicer 2.4.0+), set brim separation to 0 and EFC weakening the bond should no longer be an issue.

How do I disable the skirt?

Set Skirt → Loops to 0 — under Others → Skirt in the ATN Slicer/OrcaSlicer, or Print Settings → Skirt and brim in PrusaSlicer. Note that a minimum extrusion length, if configured, can still force extra priming loops.

Skirt vs brim vs raft — which should I use?

Skirt to prime and check levelling, brim for solid adhesion without much waste, raft only when you need maximum hold on a difficult material or a tiny footprint. Start with a brim; reach for a raft last.

Stuck on a specific failure rather than settings in the abstract? The free ATN Slicer has the Diagnose and Ask AI panels built right in beside the gcode preview — or upload a photo to our Diagnose tool in the browser and it’ll identify the defect and hand back exact, slicer-specific fixes — including downloadable .ini patches for PrusaSlicer and OrcaSlicer. Or run your gcode through the pre-flight checklist before you commit a long print.