UVtools Review

UVtools is free software for checking and editing sliced resin-printing files. I recommend it if you want to inspect suspicious layers, look for trapped resin inside a hollow model, or change a supported print setting after slicing. Its biggest drawback is the judgment it asks of you: finding a possible problem and choosing a good repair are different jobs.

If you’re willing to inspect what it flags, UVtools can earn a place between your slicer and printer. If you want one button that guarantees a successful print, it won’t meet that expectation. Your existing slicer remains the better place for major support changes.

Where UVtools fits in your resin-printing workflow

A resin slicer turns your 3D model into thin layers that the printer will build one at a time. You normally use it to position the model, add supports that hold delicate parts during printing, and choose print settings. UVtools comes after that preparation: it opens the resulting sliced file so you can examine the layers and make changes.

That distinction matters when something looks wrong. If a small part starts printing with nothing beneath it, UVtools can help you locate that area. You can then decide whether a small edit will do or whether the model needs better supports in your slicer. It gives you another way to examine the job you’ve prepared, rather than taking over all the preparation.

UVtools is free and open source under the AGPL-3.0 license, with optional donations. There’s no paid upgrade required to unlock its repair tools. What you do spend is time learning, scanning files and reviewing changes.

Use it when you have a reason to look more closely at the sliced result. A longer list of checks doesn’t, by itself, establish that you’ll have fewer failed prints.

Check that UVtools works with your setup

Get UVtools from the official sn4k3/UVtools GitHub project’s Releases page. The current release is 6.2.0. It includes fixes to layer repairs and adds GOO 5.0, 5.1 and 5.2 support, so older tutorials may describe different behavior.

Windows users have installer and portable options, plus Winget and Chocolatey installation routes. Linux and macOS packages are also available. The listed Windows minimum is Windows 10 on a 64-bit system; for Mac, plan on macOS 13 or newer and check the processor-specific package. The documented memory requirement is 8 GB plus 512 MB per CPU core. Don’t assume an old laptop will make large-file checks quick simply because it can launch the program.

For Lychee, export the sliced printer file to your computer, then open it in UVtools. Lychee also documents a UVtools quick-launch option under its Utils preferences. That shortcut is convenient, but it doesn’t establish compatibility with every export.

For Chitubox, finish slicing and save the printable file, such as CTB, before opening it in UVtools. Saving your editable project is a different step. Keep that project for support changes later.

For PrusaSlicer, UVtools documents installing printer profiles through its Help menu, checking the settings in PrusaSlicer, exporting SL1 and converting it to the printer’s required format. The setup guide is older, so check that it actually includes a suitable profile for your printer. Conversion can ignore settings the destination format cannot store.

Before using an edited file, record your slicer and UVtools versions, exact printer model, firmware version and output format revision. Firmware is the software running on the printer itself. The CTB extension alone doesn’t tell you whether a file will work. Save a separate edited copy and reopen it to check the layers and settings. You still need to confirm that your printer follows those settings.

What checking a file in UVtools involves

Start with the official wiki’s Recommended workflow page. Basic inspection uses a graphical interface; you don’t need to write code. Open a copy of your sliced file, run issue detection and select a result to inspect the affected layer. Look at nearby layers too, so you can understand how that part of the print develops.

An island is an area that starts without enough connection to the layer below. Think of the first tip of a finger appearing before anything supports it. Some warnings are false positives, so don’t delete every marked area. Tiny details and unwanted stray pixels need different treatment, even if both look small on screen.

Empty layers need context. An unnecessary blank layer at the end is different from a blank layer halfway through your model. If it’s halfway through, return to the slicer and check what should be there. Removing a layer doesn’t bring back missing model detail.

Resin traps are enclosed spaces where liquid resin can remain. In a hollow model, inspect whether drainage holes connect the cavity to the outside. UVtools can fill small unwanted pockets. For a large intended cavity, return to the slicer to place suitable drain holes; filling it would defeat the purpose of hollowing. UVtools also offers vertical hole editing, but the slicer is the more useful choice when hole direction or placement needs substantial work.

Once you understand the warnings, choose the relevant repair options. Review the result, including any remaining islands or overhangs—parts that extend beyond what’s supporting them. The pixel editor can make small additions or removals in the layer images. A large unsupported section usually calls for new supports and another slice.

Run detection again after your changes. If you use Ignore, remember that you’ve dismissed a warning; you haven’t repaired that area. Don’t chase an empty issue list by removing details you meant to print.

Keep the original slice and compare repaired areas before sending the edited file to your printer. If you return to the slicer, inspect the newly exported file again: it won’t automatically contain the layer edits you made in UVtools. That back-and-forth is part of the workload to consider, especially when a model needs extensive support work.

What to check before changing print settings in UVtools

Parameter editing is useful when the model looks right but a setting needs attention. UVtools’ Edit print parameters tool can change supported values without rebuilding the model’s supports. The important word is “supported”: a visible field doesn’t prove your printer’s firmware will use it, particularly for settings that vary between layers.

Rest times are one example. A wait before curing gives resin time to settle before the next exposure. The older UVtools rest-time guide specifically covers Chitubox 1.9.0 and CTB v4. It distinguishes a direct rest time from light-off delay, which can include movement time. Don’t copy a number between those fields or assume the guide describes a newer tilting-vat printer. Extra waits also add to print time.

Another useful tool addresses elephant foot, where the bottom of a part printed directly on the build plate spreads wider than intended. UVtools can trim pixels from the edges of bottom-layer images or make those edge pixels dimmer. Dimming requires a compatible printer and file format that support gray pixel values. Test the compensation for your printer, resin and exposure settings, and avoid applying compensation in both your slicer and UVtools. Repeat that test when you change printers, resin or exposure settings.

Those file edits are separate from changing the printer’s leveling behavior or installing firmware. Don’t treat UVtools as a verified way to prevent LCD cracking. Saturn 4 Ultra discussions mix file-setting advice with machine changes, including reports from different 12K and 16K models. They don’t establish a universal fix or recalibration procedure. For a suspected hardware fault or a claimed firmware patch, use the manufacturer’s guidance for your exact model; a UVtools repair can’t certify that the machine is healthy.

Is UVtools worth the extra step?

UVtools makes the strongest case when you’re preparing hollow models, investigating a suspicious slice or making a specific edit your slicer doesn’t conveniently offer. Its useful combination is inspection plus control: you can find an area of concern, examine it layer by layer and choose what to change.

Owner feedback supports that use, with limits. In a 2023 Reddit discussion, users described finding islands and filling unwanted resin pockets. One described repeated trips between Chitubox and UVtools because automatic repair couldn’t finish the job; another reported false island warnings in a particular file. Those accounts illustrate why the tool can be useful and why manual review remains necessary. They aren’t a measured success rate.

Processing time deserves attention too. A March 2026 owner report described one to three hours for some plates on a roughly 14-year-old W530 laptop, using detection, repair and manual filling of remaining traps. The UVtools version wasn’t identified, and that mixed workload predates 6.2.0. It isn’t a benchmark for a modern computer or the current release, but it’s a reason to try a representative file before making UVtools mandatory for every job.

There’s no solid basis here for promising a particular time saving, failure reduction or long-term printer benefit. That uncertainty doesn’t make the documented tools less useful; it means you should judge them by the problem you need to solve.

If you’re new, start with inspection and learn what one warning means before enabling broad repairs or changing exposure settings. You don’t need to learn every advanced tool to decide whether the layer view helps you.

If your existing Lychee or Chitubox workflow already gives you the checks and settings you need, staying there is the closest useful alternative. Keep UVtools available for a difficult file rather than adding work by habit. Add it routinely when the extra inspection helps you make a clear correction and you’re comfortable reviewing the result.