A brim in 3D printing is a single-layer flat area printed around the base of your model, directly connected to its edges. It works by increasing the surface area that touches the build plate, which helps the print stick better and prevents the corners or edges from lifting during the job. Think of it like the brim of a hat: a thin, flat extension radiating outward from the bottom of your object.
How a Brim Works
When your printer starts a job with a brim enabled, it first lays down a series of concentric outlines around the footprint of your model, all on the very first layer. These outlines are physically attached to the model’s edge, creating a wider “anchor” against the build plate. The larger that anchor, the harder it is for thermal contraction to pull the print’s corners upward as the plastic cools.
This is especially important because warping almost always starts at the edges of the first layer. Hot plastic shrinks as it cools, and the corners of a print experience the most pulling force. A brim counteracts that force by spreading adhesion across a much bigger area than the model’s base alone would cover.
Brim vs. Skirt vs. Raft
These three terms come up together constantly, and they do very different things:
- Skirt: A perimeter printed around your model but not connected to it. Its job is to prime the nozzle and get filament flowing consistently before the real print begins. It also lets you visually confirm that the bed is level. A skirt does nothing for adhesion.
- Brim: Essentially a skirt that’s connected to the part. It extends outward from the model’s first layer to increase bed contact area. It’s one layer thick and focused specifically on preventing warping and lifting.
- Raft: A multi-layered grid printed underneath the entire model. The part prints on top of the raft rather than directly on the build plate. Rafts provide the most adhesion support and are useful when the bed surface is uneven or the model’s geometry makes direct bed contact unreliable, but they use more material and leave a rougher bottom surface.
For most adhesion problems, a brim is the lightest-touch solution. It uses minimal filament, adds almost no print time, and is far easier to remove than a raft.
When You Need a Brim
Two main factors push you toward using a brim: the material you’re printing with and the shape of the object.
High-Warp Materials
Some filaments are far more prone to warping than others. ABS, ASA, and polycarbonate all print at high temperatures, which means the temperature difference during cooling is large and shrinkage forces are strong. Semi-crystalline materials like nylon and polypropylene also have high shrinkage rates. For any of these, a brim is often the default recommendation. PLA and PETG are more forgiving, but even they can benefit from a brim on larger prints or tricky geometries.
Difficult Geometries
Tall, narrow objects are the classic case. A cylinder that’s 8 mm in diameter and 170 mm tall has almost no contact area with the bed relative to the forces acting on it as the print grows. Any slight bump from the print head can knock it loose. A brim gives that tiny footprint a much wider base to hold onto. The same logic applies to models with thin legs, small contact points, or large flat surfaces where edge-lifting can cascade into a full detachment.
Typical Brim Settings
In your slicer software, whether that’s Cura, PrusaSlicer, Bambu Studio, or OrcaSlicer, brim settings generally come down to two key values.
Brim width controls how far the brim extends from the model’s edge. A minimum of 3 mm is a common starting recommendation, but for materials like ABS or tall prints, you might go to 5 mm or more. Wider brims provide stronger adhesion but take longer to remove afterward.
Brim gap (sometimes called “brim offset” or “brim-object distance”) is a small space between the brim and the actual model edge. This gap makes the brim dramatically easier to peel off after printing. Setting it to zero gives maximum adhesion but can make cleanup tedious. Many users report that a gap of 0.10 to 0.15 mm hits the sweet spot: the brim still holds the print firmly to the bed but peels away cleanly. Some prefer an even tighter gap of 0.05 to 0.075 mm for more demanding prints.
One thing to watch for: some slicers apply “elephant foot compensation,” which automatically shrinks the first layer slightly to prevent bulging at the base. This compensation can inadvertently create a gap between the brim and the model even when you haven’t set one, making the brim less effective. If you notice your brim isn’t actually touching the print, check whether elephant foot compensation is enabled and adjust the brim offset separately.
Removing a Brim
Because a brim is only one layer thick, removal is straightforward compared to a raft. In most cases, you can snap or peel it off by hand, especially if you’ve set a small brim gap. For a cleaner edge, a deburring tool with a swivel blade works well for tracing along the model’s perimeter and shaving off any remaining material. A flat scraper or hobby knife also does the job. The bottom edge of the print may show a slight line where the brim was attached, but light sanding smooths this out quickly.
If you find yourself spending a lot of time cleaning up brims, try increasing the brim gap by 0.05 mm increments until removal becomes easier. You’ll eventually hit a point where the brim no longer holds, so it’s a balance between easy removal and reliable adhesion.
When to Skip the Brim
Not every print needs one. If you’re printing PLA on a clean, level build plate with good first-layer adhesion, a brim just adds cleanup work for no benefit. Models with wide, flat bases already have plenty of contact area. And if the bottom surface of your print needs to be perfectly smooth, even the slight mark left by a brim attachment point may be undesirable. In those situations, a skirt (for nozzle priming) is all you need, or you can rely on adhesion aids like glue stick or a textured PEI sheet instead.