A fixed layer height is a compromise: thin enough to hide the steps on a curved surface, thick enough not to take all night. Adaptive layer height, sometimes called variable layer height, lets the slicer break that compromise by using different layer thicknesses in different parts of the same print. The idea sits close to what nozzle diameter does to layer height in general, covered in the nozzle size guide on this site, since both settings are really about how visible the steps between layers end up being.
What it actually changes
On a steep or vertical wall, a 0.28 mm layer and a 0.08 mm layer look almost the same, because the step between two layers is barely visible when the wall is close to straight up and down. On a shallow slope or a rounded dome, that same 0.28 mm step becomes an obvious ridge, since the horizontal distance the surface travels for each layer is much larger. Adaptive layer height works by looking at the local slope of the model’s surface at every height and picking a thinner layer where the slope is shallow, then relaxing back to a thicker layer wherever the wall is closer to vertical. The result is one print with genuinely different layer thicknesses stacked on top of one another, smoothed out at the transitions rather than switching abruptly from one to the next.
How slicers decide where to go thin or thick
The exact math differs slightly between slicers, but the logic is shared: each one compares the steepest slope present at a given height against the layer height needed to keep the visible step below a set threshold, then picks the layer thickness that satisfies that threshold without going thinner than necessary. Cura’s implementation, for instance, explicitly measures the angle of the outer wall and adjusts each layer’s thickness against a threshold value you can tune. Bambu Studio and OrcaSlicer expose this as a quality-versus-speed slider: push it toward quality and more of the model gets thin layers, push it toward speed and more of it gets thick layers, with the machine’s minimum and maximum allowed layer heights (something like 0.08 to 0.28 mm for a typical 0.4 mm nozzle) setting the outer bounds either way.
Where each slicer puts the control
PrusaSlicer calls this Variable Layer Height and gives you both an automatic mode driven by a quality-versus-speed slider and a manual mode where you drag directly on a height bar next to the model to thin out or thicken a specific band by hand. Bambu Studio and OrcaSlicer, both built on the same lineage as PrusaSlicer, use a near-identical adaptive slider plus a manual painting tool, with a smoothing option that runs a Gaussian filter over the transitions so the layer thicknesses blend rather than jump. Cura’s Adaptive Layers setting is more hands-off: turn it on, set a maximum variation, a step size and a threshold angle, and Cura handles the rest without a manual override built into the same panel. None of these are compatible with each other’s project files, so if you switch slicers you will need to relearn where the control lives, but the underlying concept transfers directly.
What you give up for a smoother slope
The obvious cost is slicing time, since the software now has to evaluate slope at every height rather than applying one number to the whole model, and on a detailed mesh that calculation can take noticeably longer to run. Print time is not a clean win either. You save time on the sections that get thicker layers, but the sections with thinner layers take longer than they would have at your original fixed height, so the net effect on total print time depends heavily on how much of the model is sloped versus vertical. Multi-color or multi-material prints add a wrinkle too. Bambu Studio’s own documentation notes that a shared prime tower only works if every object on the plate uses the same variable layer height settings, and neither Bambu Studio nor its relatives support variable layer height alongside organic or tree-style supports, so you may need to choose one feature or the other on a given print.
Adaptive layer height also does not replace troubleshooting a Z axis that is already misbehaving. If layers are separating or you are seeing periodic banding up the Z axis, that points to a mechanical or thermal issue rather than something a variable layer height setting will paper over; the guides on fixing layer separation and fixing Z banding and Z wobble are the better starting point for those symptoms.
When fixed layer height is the better choice
Mostly vertical parts, mechanical pieces with few curves, and anything printed for strength rather than appearance rarely benefit enough to be worth the extra slicing time and the support and prime tower restrictions. Adaptive layer height earns its keep on organic shapes, figurines, vases, and anything with domes or shallow slopes where the layer lines are the first thing anyone notices. If you are not sure which category your model falls into, slice it once with a fixed height and once with adaptive turned on, and compare both the estimated print time and a layer preview of where the thin bands actually land before committing a spool to either.
Checklist
- Adaptive layer height thins layers on shallow slopes and thickens them on near-vertical walls, within your printer’s min and max layer height limits.
- PrusaSlicer, Bambu Studio and OrcaSlicer expose both an automatic quality-versus-speed slider and a manual per-band override; Cura’s Adaptive Layers is closer to a set-and-forget toggle.
- Slicing takes longer, and total print time savings are not guaranteed since thin bands take longer to print even as thick bands take less.
- Multi-color prime towers and organic or tree supports have real compatibility limits with variable layer height, so check your slicer’s notes before combining them.
- It will not fix layer separation or Z banding caused by mechanical or thermal issues.
- Reserve it for organic and curved shapes rather than mostly-vertical mechanical parts.