Why we change layer height mid-print

Most 3D prints are produced with a single layer height applied from the bottom of the object to the top. Pick 0.2 mm, press go, come back in four hours. It is simple, predictable, and for a great many shapes it is exactly right.

It is also, for some models, a waste of the machine’s ability.

The problem with one setting

A printed object is a stack of slices. The thinner the slices, the smoother the result — particularly on curves, where thick layers produce a visible stepping, like contour lines on a map.

But thin layers everywhere means a great many more passes, and time on the machine is most of what a print costs. Halving the layer height roughly doubles the print time.

Here is the thing worth noticing: most of an object does not benefit from fine layers at all.

Think about a dragon on a plinth. The plinth is a straight-sided block. Printed at 0.1 mm or 0.3 mm it looks identical, because there is no curve for the stepping to show up on. The dragon’s face, spines and wings are where every fraction of a millimeter is visible.

A single layer height forces you to choose one compromise for both. Either you pay for fine layers on a block that gains nothing, or you accept coarse layers across a face that deserved better.

What we do instead

Our slicing software can vary the layer height through the height of a model. So on pieces where it matters, we do:

• Fine layers — down toward 0.1 mm — through faces, curves, texture and any surface that catches the light.
• Coarser layers — up toward 0.3 mm — through bases, plinths, straight walls and internal structure where nothing shows.

The result is a piece that looks like it was printed slowly, in roughly the time it would have taken to print quickly. The detail goes where the eye actually lands.

Why not do it on everything?

Because it is not free, and it is not automatic.

Someone has to look at the model and decide where the transitions belong. Put a change of layer height in the wrong place — halfway up a smooth curve, say — and you get a faint horizontal band where the surface texture shifts. That is worse than either setting on its own.

So it is a judgment call per model, not a checkbox. On a simple hook or a flat tray there is nothing to gain and we leave it at 0.2 mm. On a sculpture, a face, or anything with a dramatic silhouette, it is worth the setup.

Why we are telling you this

Because a great deal of what separates one printed object from another is invisible on a product photo.

Two shops can sell a print of exactly the same licensed model, at the same size, in the same color, and one will look noticeably better in your hands. The difference is rarely the machine. It is whether anyone spent twenty minutes thinking about the file before pressing print — layer heights, print orientation, where the supports touch the surface and what scar they leave behind.

That part does not photograph. It is, however, most of the job.

If you are curious about the machines this runs on, they are listed here — and if you want something printed with particular care, just ask.