OrcaSlicer Brim, Raft & Skirt: When and Why (2026 Settings Guide)

I printed a 200mm tall vase in PETG without a brim and watched the corner curl off the bed at hour two. Three reslices later I had it stuck down with a 5mm brim and a glue stick, same printer, same filament, same model, just one setting changed. Brim, raft, and skirt are three different tools for three different problems, and most people use the wrong one. Here’s the decision tree I wish someone had handed me before I wasted that spool.

What follows is the practical, opinionated guide I’d give a friend who’s tired of failed first layers. I’ll cover what each option actually does inside OrcaSlicer 2.3.2, when to reach for it, and the exact numbers that work in the real world. I’ll also flag the new brim_use_efc_outline toggle that landed in v2.3.2 and the underused brim ears feature that’s quietly the best fix for corner warping on otherwise-flat parts. If you want the broader picture of how these settings sit alongside everything else, the OrcaSlicer settings master guide covers the full panel.

Table of contents

• Quick decision tree, which one do you actually need
• Skirt, the free 30 seconds you should always spend
• Brim, the workhorse for warping and small footprints
• Brim types, Outer / Inner / Both / Auto / Painted
• Brim width tuning, the 3 / 5 / 8 / 10mm rules
• Brim object gap and flow ratio, the two settings that decide removal pain
• Brim ears (mouse ears), when to paint instead of widen
• New in v2.3.2, brim_use_efc_outline
• Raft, the last resort that you probably don’t need
• Raft anatomy, layers, contact distance, expansion, density
• Bed surface matters more than your slicer settings
• Material-specific recommendations
• Common problems and fixes
• Honest verdict, what 95% of users should do
• FAQ

Quick decision tree, which one do you actually need?

Before we touch a single setting, here’s the flowchart that decides everything else. I run this in my head every time I drop a model on the plate. If you only remember one thing from this article, it’s this.

The default recommendation, for a flat-bottomed slab on a tuned printer with PEI Smooth or PEI Textured, is skirt only. No brim, no raft. Most prints don’t need anything more than this and adding a brim “just in case” creates work after the print and a small scar on the part that you didn’t have to live with.

Skirt, the free 30 seconds you should always spend

A skirt is a perimeter loop printed around the model on the first layer that doesn’t touch the part. It does two jobs. It primes the nozzle so the first millimeter of actual model has consistent flow, and it gives you a visual sanity check on first layer height, squish, and bed leveling before the model starts. A skirt does nothing for adhesion. It’s basically free, costs maybe 30 seconds of print time, and there’s almost no scenario where running a 1 to 3 loop skirt is a bad idea.

You’ll find the controls in Process panel → Others tab → Skirt section. Switch to Advanced or Expert mode via the gear icon at the top of the Process panel, otherwise some of these are hidden in Simple mode.

OrcaSlicer skirt settings, line by line

I run 2 loops at 2mm distance, 1 layer high, on essentially every print regardless of material. It’s the cheapest insurance in 3D printing. If I’m dropping a fresh spool I haven’t used before, I’ll bump it to 3 loops just to watch the extrusion settle in.

When to turn the skirt into a draft shield

Set draft_shield to Enabled and crank skirt_height up to roughly the model’s height (or use Limited mode and let the slicer match the tallest object) and you’ve got a wall around the print that blocks cold air. This matters if you’re printing ABS or ASA on an open-frame machine. Heat retention next to the part keeps each new layer hotter, which keeps the layers below from contracting and pulling the corners up. It’s not a substitute for an enclosure, but it helps. Bear in mind that a tall draft shield uses real filament, and on a long ABS print it can add 10 to 30g.

One annoying caveat: per Issue 12050, skirt and brim don’t always cooperate in per-object mode. If you’re running object sequence printing and the skirt vanishes, switch skirt_type to Per object and re-slice.

Brim, the workhorse for warping and small footprints

A brim is extra material attached to the model’s first layer, fused to the outer (or inner) perimeter and extending outward by a chosen width. It glues the edges of the model to the bed by giving the first layer way more contact area. You peel it off by hand or with a fingernail or a deburring tool after the print. Brims fix roughly 90% of warping and edge-lift problems on materials like ABS, ASA, PETG, and PLA on textured surfaces. The trade-off is removal effort and a small scar at the edge of the part where the brim met the perimeter.

Honest take: if you’re not sure whether you need a brim, you probably don’t. Brims are for known-warpy materials, tall skinny parts, parts with tiny first-layer footprints, and recurring bed adhesion failures. Slap one on a flat-bottomed PLA cube and you’ve just made yourself extra cleanup work for no benefit.

The settings live in Process panel → Others tab → Brim section, right below the skirt block. Below is a sliced view of a tower with a generous brim. You can see the green Brim line type lighting up around the base, which is how I sanity-check that the brim actually attached itself to the perimeter before I send the file to the printer.

OrcaSlicer brim settings, line by line

Brim types, Outer / Inner / Both / Auto / Painted

The Type dropdown is where most people pick wrong. Here’s how I think about each option:

I leave most prints on Auto. The slicer’s heuristic is conservative, it caps computed width at 20mm and at 1.5x the calculated thermal length, and if the computed width comes out under 5mm AND under 1.5x thermal length, Auto Brim outputs nothing. That’s a sensible default. The only times I override it: when I know the geometry is going to fool the heuristic (a tall thin tower with a wide flat base), or when I want mouse ears specifically.

Brim width tuning, the 3 / 5 / 8 / 10mm rules

If you’re doing manual width, here’s how I size it. These aren’t arbitrary, they’re what I’ve landed on after enough failed prints to fill a recycling bin.

Going wider than 10mm rarely helps. By the time the corners are 10mm out from the part, the brim itself starts curling at its own outer edge, and you’re not adding much grip. If 10mm isn’t enough, the answer isn’t 15mm, it’s a draft shield, an enclosure, or a different bed surface.

Below is the same tower from another angle, where you can see the brim lip clearly above the build plate. The brim is a single layer thick, that’s what makes it removable. If you ever see a brim that looks two or three layers tall in preview, you’ve accidentally enabled skirt_height on the wrong setting or set raft_layers to something nonzero.

Brim object gap and flow ratio, the two settings that decide removal pain

Most “the brim won’t come off” or “the brim ripped a chunk out of my part” complaints trace back to two settings: brim_object_gap and brim_flow_ratio. Defaults are 0.1mm and 1.0. Here’s how to move them.

If the brim won’t separate from the part: increase the gap to 0.15 or 0.2mm. This gives you a thin air channel between brim and perimeter that lets the brim snap off cleanly. PETG specifically loves to over-bond, so I run PETG at 0.15mm by default. The Discussion 4776 thread in the OrcaSlicer repo is full of users with this exact problem and the fix is almost always a wider gap.

If the brim falls off mid-print: drop the gap to 0.05mm and bump brim_flow_ratio to 1.05. This forces more material into the brim-to-part connection. Good for ABS, where adhesion failure mid-print is much worse than removal pain after.

If the brim won’t actually connect to the part at all: this is the Elephant Foot Compensation problem. EFC shrinks the first-layer perimeter inward to compensate for squish, but the brim was generated against the original outline, so it ends up offset from the post-EFC perimeter and never touches it. The fix that landed in v2.3.2 is the brim_use_efc_outline toggle, see the next section.

If brim removal scars the part: drop brim_flow_ratio to 0.95. Less material in the connection means the break point is cleaner. You’ll trade a small amount of adhesion strength for a cleaner edge.

Brim ears (mouse ears), when to paint instead of widen

Brim ears are the underused option in the brim panel. Instead of running a full brim around the entire perimeter, you paint small disc-shaped patches only at the corners that actually warp. They use a fraction of the filament of a full brim, are trivial to remove, and target only the at-risk geometry.

Set brim_type to Painted, then go to the Prepare tab and click the Brim Ears Painting tool. The parameters you’ll see:

• Head diameter, the size of each ear circle. 10 to 15mm covers most use cases.
• Max angle, geometry sharper than this triggers an auto-placed ear.
• Detection radius, the Ramer-Douglas-Peucker threshold. Smaller value places more ears.
• Section view, preview slider for ear placement.
• Auto-generate points, automatically detects suitable corners.

I let Auto-generate do the first pass, then add or remove ears manually based on what I know about the part. On a typical PETG bracket with four right-angle corners, four ears at 12mm diameter give me the same anchoring as a 5mm full brim with maybe 20% of the filament and a fraction of the cleanup time. Mouse ears beat a full brim every time on parts where you can identify the at-risk corners by eye.

One caveat from Issue 9702: the Brim Ears toolbar can occasionally reset the per-object brim option. After painting ears, double-check that the per-object brim setting in the right panel still reflects what you wanted, because painting ears is what you want, not painting ears AND a full perimeter brim.

New in v2.3.2, brim_use_efc_outline

This one’s recent enough that most existing tutorials don’t mention it. If you have Elephant Foot Compensation turned on (and you should, on most printers), the slicer reshapes the first-layer perimeter to counter the bulge that happens when hot plastic squishes against the bed. Without the new toggle, the brim is generated against the original perimeter, so it sits a fraction of a millimeter away from the actual first-layer wall and never bonds.

Turn on brim_use_efc_outline in the Brim section and the brim now follows the post-EFC outline. The brim and the model perimeter share a real edge, and adhesion works the way you’d expect. If you’ve ever printed a brim that looked correct in preview but came off the bed as a separate ring while the model lifted, this is the fix.

I leave it on by default for any print using EFC. Cost is zero, benefit is a brim that actually connects.

Raft, the last resort that you probably don’t need

A raft is a separate sacrificial platform printed underneath the entire model. The model sits on top of the raft, and the raft sits on the bed. After the print, you discard the raft. Rafts add significant time and material (often 20 to 40 minutes and 5 to 15g of filament), and they leave a textured or rough underside on the model. There’s no way around the texture, it’s a consequence of how the contact layer separates from the model.

Honest take: in three years of weekly printing across PLA, PETG, ABS, ASA, TPU, PC, and PA-CF, I’ve used a raft maybe four times. Three of those four were Nylon or PC blends without a heated chamber, and the fourth was an old printer with a permanently warped glass bed I couldn’t replace. If you’re considering a raft and your bed is flat and you’re not printing PA or PC, you almost certainly want a wider brim or better surface prep instead.

Rafts exist for three real cases:

1. A severely warped or unrepairable bed where leveling and mesh compensation can’t keep up.
2. Very high-shrinkage materials (Nylon, PC, PC blends) without a heated chamber.
3. Parts whose footprint is so small or spindly that even a brim doesn’t give enough contact area.

The raft settings live in Process panel → Support tab → Raft section, not under Others where you might expect. This catches a lot of users out, because the brim and skirt are on the Others tab and most people assume the raft is the third option in the same place. It’s not, it’s filed under Support because the raft and supports share the same interface-layer logic.

There’s also a known UI quirk per Issue 5478: searching for “Raft contact Z distance” in the search box returns the setting but the link goes nowhere. The setting is real, it lives at raft_contact_distance in the Support tab, and it only becomes visible once you set raft_layers to a nonzero value.

Raft anatomy, layers, contact distance, expansion, density

A raft in OrcaSlicer is built from the bottom up like this:

Here’s the full settings table:

How many layers, and how to tune contact distance

Most raft uses want 3 to 4 layers total. Two is the bare minimum and tends to flex during the print, four is the sweet spot for warpy materials, five or more is overkill that just adds time. The Bambu Lab forum consensus on ABS warping (linked here) is identical: 3 to 4 layers, increase first-layer density, slow first-layer speed.

For the contact distance:

• If the raft and model fuse so hard you damage the part during removal: increase raft_contact_distance from 0.1 to 0.15mm. The wider air gap means the contact layer doesn’t quite touch the model bottom layer, and it pops off cleanly.
• If the model lifts off the raft mid-print: drop it back to 0.08 to 0.1mm. The model needs to actually grip the contact layer, and a too-large gap leaves it floating.

Material and time penalty

A typical 100mm x 100mm base raft adds roughly 8 to 15g of filament and 15 to 35 minutes of print time, depending on layer height and speed. Bigger footprints scale linearly. On a 24-hour print, an extra 35 minutes is noise. On a 90-minute small part, you’ve just doubled the print time. That’s part of why I push back on rafts for small models: the proportional cost is huge.

Removal almost always leaves a textured underside on the model. Sometimes you can sand it smooth, sometimes the texture is fine and nobody will see it (functional brackets, internal parts), and sometimes it’ll annoy you. Plan around it.

Bed surface matters more than your slicer settings

Here’s the thing nobody tells you: 80% of bed adhesion problems are bed surface problems, and another 15% are first layer height problems. Brim, raft, and skirt are tools to compensate for the remaining 5% (or to compensate for a bad surface choice you’ve already made). If your PEI sheet is greasy or your glass plate is oily, no brim width on earth will save you. Wipe with isopropyl alcohol first, dry with a fresh paper towel, then start printing.

This matrix is what I’d hand someone setting up a new printer:

PETG warning, twice because it matters: PETG fuses to bare smooth PEI hard enough to chip the PEI off the spring steel. ALWAYS use a glue stick or hairspray as a release layer with PETG on smooth PEI. This is independent of brim choice. I’ve seen brand-new PEI sheets ruined in two prints because someone skipped the glue. Full settings are over in the OrcaSlicer PETG settings guide.

Garolite for Nylon: if you’re printing Nylon (PA, PA-CF, PA-GF) regularly, the right answer isn’t a fancier brim or a thicker raft, it’s Garolite (FR-4 fiberglass sheet). Nylon mechanically grips Garolite the way no smooth surface can, and you’ll go from brim-and-raft-and-glue to skirt-only basically overnight. MatterHackers has the canonical write-up if you want details on the surface.

If you want to see how the brim settings interact with multi-part plates, here’s a top-down sliced view of the same model arranged on a multi-object plate. Notice how the brim wraps each part individually, and the skirt encloses all of them as a single combined loop. Setting combine_brims to On is what merges touching brims into continuous loops, which is cleaner than letting each part have its own boundary right next to its neighbor’s.

Material-specific recommendations

Quick reference for the materials people actually print. These assume a tuned printer with a reasonably flat bed.

For full per-material profiles, the OrcaSlicer filament settings overview ties this back to temperature, fan, and flow tuning.

Common problems and fixes

Brim won’t actually connect to the part

The number-one cause is brim_object_gap set too high. Drop it to 0.1mm and re-slice. The number-two cause, on parts where you have Elephant Foot Compensation enabled, is that the brim was generated against the pre-EFC outline. Turn on brim_use_efc_outline (new in v2.3.2) and the brim will follow the post-EFC perimeter and bond properly. Discussion 4776 in the OrcaSlicer repo has a long thread of users hitting exactly this problem.

Brim is harder to remove than the print

Two adjustments. First, increase brim_object_gap from 0.1 to 0.15 or 0.2mm, the brim now snaps off cleanly because there’s a thin air channel between brim and perimeter. Second, drop brim_flow_ratio to 0.95, which thins the bond at the break point. Both together if it’s really stubborn. PETG is the worst offender here, ABS is second worst.

Raft fuses to the model

Increase raft_contact_distance from 0.1 to 0.15mm. That extra 0.05mm of air gap is usually enough to let the raft pop off without taking surface material with it. If 0.15 doesn’t do it, try 0.2mm, but at that point you risk the model lifting off the raft mid-print. If you’re soluble-interface printing (PVA or HIPS top layer), this setting is ignored and you don’t have this problem to begin with.

Skirt looks fine but the model still won’t stick

The skirt isn’t there for adhesion, remember. A clean skirt only tells you the nozzle is primed and at the right height. If the skirt looks great but the model lifts, your adhesion problem is elsewhere: bed surface contamination, wrong bed temperature for the material, first-layer Z too high. Wipe the bed with IPA, verify bed temp, drop Z by 0.02mm, and try again. The OrcaSlicer troubleshooting master guide has a longer first-layer diagnostic walkthrough.

Skirt and brim don’t print together with object sequence printing

Per Issue 12050, in object sequence (per-object) print mode, the default Combined skirt type doesn’t always cooperate with brims. Switch skirt_type to Per object, and the skirt will be printed once per object alongside its brim. This also matters if you’re using object sequence printing for clearance reasons and you really do want a skirt on each object as a primer.

Honest verdict, what 95% of users should do

If you take nothing else from this:

1. Run a 2-loop skirt at 2mm distance on every print. It costs you 30 seconds and gives you a free first-layer sanity check.
2. Leave brim on Auto. Trust the slicer to add a brim when geometry warrants it. Override only when you know better than the heuristic.
3. If you see warping, add a 5mm brim. If 5mm isn’t enough, go to 8mm. If 8mm isn’t enough, the answer is probably a draft shield, an enclosure, or a different bed surface, not 15mm of brim.
4. Don’t use a raft unless your bed is broken or you’re printing Nylon or PC without a chamber. Even then, fix the underlying problem first if you can.
5. If you’re on smooth PEI and printing PETG, glue stick is non-negotiable. Yes, every time. Yes, even if it stuck last time.
6. Turn on brim_use_efc_outline if you have Elephant Foot Compensation enabled. It’s new in v2.3.2 and it fixes the most annoying brim failure mode for free.
7. Consider mouse ears (Painted brim type) for parts where you can identify the at-risk corners by eye. Less filament, less cleanup, same result.

Most prints don’t need any of this beyond the skirt. The day you stop reflexively adding a brim to every PLA print is the day your prints get cleaner edges and your post-processing time drops by half. For more on dialing in adjacent settings, the adaptive layer height guide and the normal vs tree supports comparison are the other two pillars I’d read after this one. The fuzzy skin guide covers an unrelated but underused surface feature if you’re going down the rabbit hole.

FAQ

Do I need both a brim and a skirt?

You can run both, and OrcaSlicer handles it fine. The skirt prints first as a separate perimeter loop a few millimeters out from the brim, the brim prints attached to the model. The only caveat is per-object printing, where Combined skirt type can drop one or the other (set to Per object as the workaround). For most users, brim plus 1 to 2 loop skirt is the standard combo on warpy materials.

Why is the raft setting under Support and not Others?

Because the raft’s top contact layer uses the same logic as a support interface layer. OrcaSlicer treats the raft as “support that goes everywhere under the part”, so it lives in the Support tab next to support density and interface settings. It catches a lot of users out the first time, but once you know it’s there, you’ll find it.

Will a wider brim always give better adhesion?

No. Past about 10mm, the outer edge of the brim itself starts to lift, and you’re not gaining anchoring power. You’re just adding cleanup time and a wider scar at the model edge. If 10mm isn’t enough, the answer is a draft shield, an enclosure, a different bed surface, or a raft, not a wider brim.

Can I use a brim and a raft together?

You can, but you almost never want to. The raft already provides a much wider footprint than the model itself, so a brim around the raft is redundant. The exception is if the raft itself is lifting at its corners, in which case yes, add a brim to the raft, but at that point your real problem is the bed surface or temperature.

What’s the difference between mouse ears and brim ears?

They’re the same thing. “Mouse ears” is the older community term for the small disc-shaped patches placed at corners. OrcaSlicer’s official UI calls them “brim ears” and the painting tool is in the Prepare tab. If you read older Cura or PrusaSlicer tutorials, you’ll see “mouse ears” used interchangeably.

Do I need to disable Elephant Foot Compensation if I use brim_use_efc_outline?

No, the new option is designed to work alongside EFC. EFC stays on and reshapes the first layer, the new toggle just tells the brim generator to use that reshaped outline instead of the original. Leave EFC at whatever you had it at, just turn the new option on.

Related OrcaSlicer guides

• OrcaSlicer Settings Master Guide: Every Setting Explained (2026)
• OrcaSlicer for Anycubic Kobra 2 / Neo / Plus / Max: Setup and Best Settings (2026)
• OrcaSlicer for Elegoo Centauri Carbon: Setup and Best Settings
• OrcaSlicer for Snapmaker Artisan, J1 and 2.0: Setup Guide
• How to Send G-code Wirelessly From OrcaSlicer: Per-Printer Walkthrough