How to Prepare STL Files for Printing Minis

A great sculpt can still die an ugly death on the build plate. A sword warps, a cloak peels loose, or a hero’s face comes out softened like it has spent too long in the Warp. Learning to prepare STL files for printing is what turns an instant download into a sharp 32mm warrior, a clean display beast, or the centerpiece your warband deserves.

This is not about drowning every model in supports until it resembles a resin hedgehog. It is about reading the miniature: where its weight sits, where resin can pool, which details must stay pristine, and which surfaces can hide a support scar. The right setup protects the sculpt and makes cleanup far less miserable.

Start With the Right STL Version

Before you open your slicer, check what came in the download. Many miniature releases include several versions of the same model: unsupported parts, pre-supported parts, hollow versions, solid versions, alternate weapons, scenic bases, or split components for smaller printers. Do not assume the largest single file is the best choice for your machine.

Pre-supported files are usually the fastest route to the plate. They are built around a specific orientation and support strategy, often with contact points placed away from faces, armor trim, and focal details. For a detailed grimdark character with a raised gun, banners, and a pile of battlefield rubble underfoot, that saved setup time matters.

Unsupported files offer more control. Choose them when you know your printer’s behavior, use a different resin than the creator anticipated, want a custom pose, or need to fit parts around an already-packed plate. They are also useful if you prefer heavier supports than the provided setup. Neither option is automatically superior. Pre-supported files reward speed and consistency; unsupported files reward experimentation.

Open the file in your slicer and inspect it before adding anything. Confirm that the model is not missing a hand, weapon, base insert, or separate head. Look for obvious mesh errors such as holes, paper-thin surfaces, or inverted geometry. Most modern slicers can flag and repair simple non-manifold errors, but a repair tool cannot restore detail that was never present in the mesh.

Prepare STL Files for Printing at the Correct Scale

Scale mistakes are a cruel kind of hobby tragedy. A goblin intended to menace a 32mm battlefield can become an 80mm monument, while a hulking orc can arrive small enough to lose his threats in the underbrush.

First, understand what the scale label means. A 32mm-scale miniature generally refers to the approximate height from the base to eye level for an average human-sized character, not every model’s total height. A crouched mutant, a towering brute, and a flying creature will naturally fall outside that measurement. Compare the STL dimensions against a familiar miniature, base size, or the dimensions provided with the release before you print.

Avoid changing the scale independently on separate components. If you scale a body to 90 percent but leave its weapon, head, or base at 100 percent, assembly becomes a small nightmare of gaps and misaligned joints. Select all related parts and scale them together. For multipart kits, check pegs and sockets after scaling, especially if you have moved far from the intended size.

Scaling also changes printability. Reducing a model can make spear shafts, fingers, chains, and spikes too delicate to survive cleaning. Enlarging it may reveal layers or make previously solid sections too heavy. If you are moving a miniature dramatically up or down in size, inspect its thinnest parts and reconsider support placement rather than trusting the original arrangement blindly.

Orientation Is Where the Print Is Won or Lost

Flat is rarely your friend in resin printing. A miniature placed directly upright can create large cross-sections that fight the release film with every layer. That force can pull a print from its supports, distort broad surfaces, or leave a failed slab fused to the vat.

For unsupported models, begin by tilting the miniature roughly 25 to 45 degrees off the build plate, then rotate it slightly from side to side. The goal is to reduce large, sudden layer changes and give each new section enough support as it forms. There is no sacred angle. A heavily armored Iron Grin Mob brute has different needs than a thin-winged dark-fantasy demon.

Think about the model’s visual priority. Put supports on the underside of a cloak, the back of a boot, the bottom of a weapon, or hidden contact points inside an assembly joint. Keep them away from faces, chest icons, shield fronts, and broad smooth armor plates whenever possible. A support mark on a rocky base is a quick scrape. A support mark across a character’s eye is an insult from the resin gods.

Use heavier supports to carry the model’s earliest, heaviest load-bearing sections. Medium supports can stabilize major forms, while light supports protect thin details and prevent islands. An island is any section that begins printing without connection to a previous layer. Slicer previews are your best defense here. Move through the layers and look for tiny detached pixels, the start of a weapon tip, an overhanging elbow, or a dangling trophy that has no path back to the main supported mass.

Do not overcorrect by placing heavy supports everywhere. Excessive contact points damage detail, increase cleanup, and can flex delicate pieces as they cure. Strong, deliberate support placement beats a forest of random pillars.

Hollow Large Models and Give Resin a Way Out

For standard infantry-sized miniatures, solid printing is often perfectly reasonable. Small solid parts are durable, simple, and less likely to trap uncured resin. Larger creatures, display busts, terrain pieces, and thick scenic bases are different. Solid prints consume more resin, create more heat during curing, and may be unnecessarily heavy.

Hollowing reduces resin use, but it introduces a non-negotiable requirement: drainage. Every hollow model needs drain holes placed at the lowest points in its print orientation so liquid resin can escape. It also needs at least one higher vent hole to let air enter and prevent a vacuum from locking resin inside.

Place drain holes where they will be hidden after assembly whenever possible: beneath a base, inside a socket, under a cloak, or on the underside of a monster’s body. Use holes large enough for resin to flow and for cleaning fluid to reach the cavity. Tiny decorative pinholes may look discreet, but they often clog and defeat the point.

A sealed hollow print can retain liquid resin for months. If it later cracks, that resin can leak onto your shelf, your paint station, or a treasured unit of finished miniatures. After washing, flush hollow pieces thoroughly and make sure their interior is dry before final curing. Hollowing is useful, not mandatory. For a compact 32mm character, the extra workflow may not be worth it.

Dial In the Slicer Before You Commit a Full Plate

STL preparation does not end with supports. Your slicer settings must match your printer, resin, room temperature, and layer-height goals. A preset from another hobbyist can be a good starting point, but it is not a blood oath. Different mono screens, resins, and workshop temperatures produce different results.

Use a calibration print when changing resin or when failures start appearing. Exposure that is too low can cause weak supports, incomplete details, and broken parts. Exposure that is too high can soften fine features, close shallow recesses, and make support removal more brutal. Lift speed matters too: fast lifts save time but can increase peel stress on large or poorly supported sections.

For detailed tabletop minis, layer height is a trade-off. Finer layers can improve surface smoothness and subtle detail, but they add print time and do not fix poor orientation or bad exposure. A properly supported model at a sensible layer height usually looks better than a badly supported model printed painfully slowly.

Before launching a crowded build plate, print one challenging component first. Test the banner, the outstretched weapon arm, or the largest body section. One small trial can save a vat of resin and an evening of scraping failed supports off the film.

Wash, Cure, and Inspect Before Assembly

A successful print is not finished when the plate rises. Remove supports after washing but before full curing when possible. The resin is firmer than fresh from the printer yet still flexible enough for support contacts to release with less damage. Wear gloves, work in a ventilated area, and follow the safety guidance for your chosen resin and cleaning solution.

Wash recesses, undercuts, and hollow interiors thoroughly. If a miniature has deep armor vents, clustered trophies, or a skull-strewn base, old resin can hide in places that look clean at first glance. Let the print dry completely, then cure it according to the resin manufacturer’s guidance. Too little curing leaves the piece weak; too much can make thin parts brittle.

Inspect every part under strong light before assembly. Trim tiny nubs, test-fit pegs, and gently sand only where needed. A clean dry fit catches warped tabs and narrow sockets before glue turns a five-minute adjustment into a permanent grudge.

Your slicer is part workshop, part battlefield command table. Take a little time to inspect the model, choose the right orientation, and test settings when something changes. Then the next named gunner, pocket-sized menace, or towering warboss has a much better chance of arriving on the plate ready for paint, glory, and a place in the collection.