What Combing Mode Actually Controls
Every travel move in a print (any repositioning where the nozzle isn’t extruding) has to get from point A to point B somehow. Without combing, Cura sends the nozzle in a straight line, retracting first if the distance is long enough. With combing on, Cura instead tries to route that straight-line move through plastic that’s already been printed on the current layer, staying inside the part instead of crossing open air above the bed or outside the model.
Why does that matter? Because a nozzle that’s still slightly pressurized (or a bit oozy from a partial retraction) leaves a trace wherever it travels. If that trace lands on bare infill or inside a wall that gets printed over later, nobody ever sees it. If it lands on a visible top surface, you get a thin string or a faint smear right where you don’t want one. Combing is Cura’s way of hiding those traces inside the print rather than eliminating the ooze itself.
This is also why combing reduces retraction count. If Cura can route the head through the interior of the part without crossing a gap or an unprinted region, it often skips the retraction and travel-move waiting entirely, since the nozzle is moving over material that will get reprinted or was never going to be seen anyway. Fewer retractions means less wear on your extruder gears, less risk of chewing through filament on a Bowden setup, and a small but real speed gain.
Cura’s own description of the setting sums it up as movements that avoid pressure changes inside the nozzle, routing around the print instead of retracting whenever it can. That’s the whole idea in one sentence.
The Four Options in Cura
Combing Mode lives under Travel settings, and in current Cura versions (marked as an expert-level setting, so you’ll need to switch to Expert or Custom mode to see it directly) it offers four choices.
Off
No combing at all. Every travel move goes in a straight line and follows your normal retraction settings on its own terms. This is the safest option if you’re chasing something else, like troubleshooting whether combing itself is causing an artifact, but it also means you lose the ooze-hiding benefit entirely. Most people don’t want this as a permanent setting.
Everywhere (labeled "All" in some Cura versions)
The nozzle is allowed to travel through any part of the currently printed layer, including the outer walls and the visible skin (top and bottom solid layers). This gets you the most retraction savings and the fastest print, but it’s also the riskiest option for finish, because the nozzle can drag or ooze right across a surface you’re going to look at. If you’ve ever seen a print with faint scratch-like lines running across a flat top layer, a combing mode set to Everywhere with a slightly under-tuned retraction is a common cause.
Not in Skin
This is the default in most Cura profiles, and for good reason. The nozzle is allowed to travel through walls and infill, but Cura tries to avoid routing moves across skin areas (the solid top/bottom layers) whenever it can. It’s a middle ground: you still get combing’s retraction-reduction benefit for the bulk of the print, but the layers people actually see stay cleaner because the nozzle isn’t crossing them during travel.
Within Infill
The strictest option. Cura restricts travel moves to infill only, avoiding both the outer walls and the inner walls in addition to skin. Any oozing or dragging during a move gets buried inside the sparse infill lattice where it’s structurally and visually irrelevant. This is the choice for parts where wall finish matters most, vases, enclosures, anything with a smooth outer shell and low infill density. The tradeoff is that Cura has fewer legal paths to route through, so it falls back to retraction more often, and on solid or high-infill parts it may barely have any infill region to route through at all.
There’s a companion setting worth knowing about here: Combing Max Distance, which only applies when Within Infill is selected. It caps how far a combed move is allowed to travel before Cura gives up and retracts instead. Without a cap, a move could wander a long way through winding infill channels just to avoid a straight line over a wall, and that detour can cost more time than a normal retraction would. Setting a sensible max distance keeps Within Infill useful instead of turning small parts into a maze.
Combing, Retraction, and Z-Hop Working Together
Combing doesn’t replace retraction, it reduces how often retraction happens. When a travel move can’t be routed through legal territory (say, the nozzle has to jump between two separate islands, or the distance exceeds your minimum travel threshold), Cura still retracts exactly as your retraction distance and speed settings dictate. So your retraction tuning still matters even with combing on. If your retraction distance is too short or your speed too slow for your hotend, you’ll still see stringing on the moves combing couldn’t avoid.
Z-hop is a separate mechanism and it’s worth being clear about the difference. Z-hop lifts the nozzle vertically before a travel move so it physically clears any bumps or already-printed walls in its path, preventing collisions and scarring from dragging across a printed feature. Combing reroutes the move horizontally to stay over safe territory; z-hop moves the nozzle up so that even if it does cross something, it won’t touch it. Cura even has a "Z Hop Only Over Printed Parts" option, which only triggers the lift when the nozzle is actually about to cross a printed section rather than every single travel move, keeping the extra vertical motion to a minimum.
In practice, combing and z-hop solve different problems. Combing is about hiding oozing marks. Z-hop is about avoiding physical collisions with tall features, which matters more on prints with lots of separate towers or spikes where the nozzle would otherwise have to fly directly over them. Running both together is common and generally safe: combing keeps travel paths sensible, and z-hop is your backup for the cases combing’s routing can’t fully dodge.
Where Combing Goes Wrong
The most common complaint with combing is exactly the failure mode you’d expect from Everywhere or an aggressively tuned Not in Skin setup: visible zit marks or faint lines on top surfaces where the nozzle passed over during a travel move. If you’re seeing this, the fix is almost always to switch to Not in Skin (if you’re on Everywhere) or Within Infill (if Not in Skin still isn’t cutting it), rather than cranking retraction distance further, since the underlying issue is the travel path, not the retraction itself.
The second issue shows up on models with very high infill or fully solid infill. Within Infill needs actual infill space to route through, and on a near-solid part there isn’t much of it, so Cura falls back to retracting constantly or, in edge cases, still has to cross skin because there’s nowhere else to go. If you’re printing something at 80-100% infill and using Within Infill, you may not see the benefit you expect, and Not in Skin is usually the more reliable choice for dense parts.
Small, detailed prints can also suffer from combing detours that eat more time than they save, especially with Within Infill and no distance cap. This is what the Combing Max Distance setting exists to fix, so if slicing time balloons unexpectedly after switching combing modes, check that value before assuming something else broke.
Combing also interacts oddly with models that have very little infill or are mostly hollow. With sparse infill and Within Infill combing selected, there may simply not be a legal path between two points, forcing more retractions than a denser part would need. If you notice retraction counts going up instead of down after switching to a stricter combing mode, that’s usually why.
Quick Guidance
For most day-to-day printing, Not in Skin is the setting to leave alone and forget about. It’s Cura’s default for a reason: it captures most of the retraction savings while keeping visible surfaces clean. Reach for Within Infill specifically when top and outer wall finish is the priority and you’re not running dense infill. Use Everywhere only if you’re chasing print speed above all else and your retraction is already well tuned, since it’s the setting most likely to put a visible mark somewhere you’ll notice it. And if you’re debugging an odd travel-path artifact, temporarily switching to Off is a quick way to confirm whether combing is actually the culprit before you go tuning anything else.
PrusaSlicer and OrcaSlicer don’t call this setting “combing,” but they route travel moves in similar ways behind different labels. If you’re deciding between slicers rather than tuning one you’ve already picked, the Cura vs PrusaSlicer vs OrcaSlicer comparison covers how the three actually differ day to day.