# UmaViewer: a standalone viewer for Uma Musume models and animations > UmaViewer is a Unity application that opens the asset data of Uma Musume: Pretty Derby so you can look at character models, swap costumes and animations, play the live audio with lyrics, and export animations to MMD. It needs the game's full data download and a Windows exemption from Smart App Control, and its asset export and scenery support are still marked incomplete. **katboi01/UmaViewer** — Asset Viewer for Uma Musume - Repository: https://github.com/katboi01/UmaViewer - Stars: 899 · Forks: 178 - Language: C# - License: not declared - Published: 2026-10-20 · Updated: 2026-10-20 · Language: en - Canonical page: https://hysenlabs.com/projects/katboi01-umaviewer ## The unsigned build is the first thing that stops you The very first item in the README is a warning, and it is the one thing a new user is most likely to hit. If you see the message Failed to load il2cpp, or the application simply will not start on Windows, it may be blocked by Windows Smart App Control. The fix is given as a path through the Windows settings, from App and browser control to Smart App Control settings and then Off. The path through the Windows settings, as the README writes it: ```text Windows Security → App & browser control → Smart App Control settings → Off ``` The cause is stated plainly: Windows is blocking unsigned builds, and the program should start normally after moving it to a local folder or disabling Smart App Control. That last part matters, because it means the folder you extract to is part of the problem, not only the setting. The failure mode is not graceful either: a blocked binary gives you an il2cpp error rather than a message about code signing, which sends people looking for a Unity problem instead of a Windows policy problem. Turning off a system security control to run a hobby tool is a real trade, and it is worth deciding deliberately rather than reflexively, since Smart App Control is a default that protects against exactly this class of unsigned application. ## Finding the game data is the part that varies by install The tool needs Uma Musume: Pretty Derby with the full data download, and the data location depends on how old and how fresh the installation is. Older DMM and Steam installations keep it under the Cygames folder in LocalLow, while fresh installations put it in the Umamusume_Data Persistent directory inside the installation folder. Rather than trust either, the README tells you to confirm the file listing in the target folder, and it gives the shape you are looking for: a meta folder, a master folder containing master.mdb, and a dat folder with numbered subdirectories such as 2A and 2B. The application tries to detect the data folder automatically on startup. If the detection fails or an error appears, you go to Settings, then to the Other tab, and use Change DataPath to select the folder manually. For the English and Global builds there is one extra step: set WorkMode to Default and Region to Global in that same Other settings tab. The viewer currently supports only the default work mode, which means you need to have used the Download All button in the game's own settings, and anything else will not populate correctly. ## Installing it is a zip file, not an installer There is no installer and no package manager entry. The process is short. Download the most recent UmaViewer.zip from the Releases tab, extract the archive anywhere, including over a previous version, and run UmaViewer.exe. The release list is a stream of auto-generated builds with the commit hash in the name, such as AutoBuild with a long hash and the matching UmaViewer build, and the most recent of them is from 2026-07-02. The last push to the repository was on 2026-07-18, so the source and the binaries are being worked on. For anyone who wants to build it rather than download it, the developer instructions are equally short. Unity Hub with Unity Engine version 2022.3.62f1 is recommended, with the note that it should be possible to run on newer 2022.3.X versions. You clone or extract the repository, import and open the project in Unity Hub, where missing files should be repaired automatically, and then open the Assets/Scenes/Version2 scene. If the console shows errors, the JSON .NET For Unity package may be required. The project is a standard Unity layout with an Assets folder, a Packages folder, ProjectSettings and a UserSettings folder. ## What works, what is partial, and what is missing The feature table uses a three state legend, working, incomplete and unsupported, and reading it honestly is more useful than the screenshot gallery. What works includes viewing the main character models and their animations, swapping costumes and animations between characters, chibi models and animations, mob models for the non-player characters, facial animations with custom sliders, cloth and hair physics, playing the live audio with lyrics, exporting animations to MMD, and recording animations as gif files or taking screenshots. The incomplete items are viewing props, scenery and live scenes, and exporting models. The table also states that all characters and animations are supported, and the images show mobs and background characters as well as mixed outfits. The model export gap is the one to think about before committing, since exporting animations to MMD and exporting models are different things, and only the first is listed as working. ## This is a viewer, not a mod, and the difference is the point UmaViewer is described as a Unity application that makes it easy to view assets from the game, and the distinction from a mod is what makes the project safe to use and limited in what it can do. It reads the game data, presents it, and can export animation data in a format other tools understand. It does not alter the game. That has two consequences worth naming. The first is that the licensing question stays simple, because you are not shipping the game's assets with a modified game. The second is that the viewer can support every character and every animation the game ships without any of them being individually reverse engineered, since the data format is read generically. The credit list at the bottom names where one piece of the decoding came from, with a special thank you to MarshmallowAndroid for the acb and awb decoder, which is the kind of acknowledgement that tells you the project builds on a community decoder for the archive format rather than having solved the format alone. ## The related project shows where the fork went The README points at one related project, UmaChat by kagari, described as a model viewer fork that lets you chat with the characters using AI plus text to speech. That is a useful signal about the codebase, because it tells you the viewer is a forkable starting point rather than a sealed application, and that someone has taken it in a direction the author did not. It also gives you a comparison point. UmaViewer focuses on the inspection and export side, with the animation tools, the recording and the MMD export, while the fork takes the same asset browsing and adds a conversation layer on top. If you want the asset pipeline, the base project is the one with the feature table filled in. If you want the interaction model, the fork is further along. The project also uses a Visual Studio configuration file, the .vsconfig, in the repository root, which is the file that makes the required editor components visible when the project is opened. ## Conclusion UmaViewer suits a Uma Musume player or 3D hobbyist who wants to inspect the game's models, reuse the animation set in another pipeline, or record the character animations, and who is willing to install the game's full data set and adjust a Windows security setting. It does not suit someone who wants to extract the game's assets for redistribution, since model export is marked incomplete, and the tool is a viewer rather than a mod. Before installing it, confirm the game's data was downloaded in full, set WorkMode to Default and Region to Global in the Other settings tab if you play the English or Global build, and read the Smart App Control note, because an unsigned build will simply refuse to start on a current Windows install. ## FAQ ### Why does UmaViewer show Failed to load il2cpp on Windows? Windows Smart App Control may be blocking the unsigned build. The README says to turn it off through Windows Security, App and browser control, Smart App Control settings, Off, and notes that the program should also start normally after moving it to a local folder. ### Where does UmaViewer look for the Uma Musume game data? Older DMM and Steam installs keep it in the Cygames folder under LocalLow, while fresh installations keep it in the Umamusume_Data Persistent directory inside the install folder. The viewer detects the folder automatically, and if that fails you set it manually with Change DataPath in the Other settings tab. ### Can UmaViewer export the character models? Not yet. The feature table marks model export as incomplete, while exporting animations to MMD, recording gif files and taking screenshots are all listed as working. Viewing props, scenery and live scenes is also marked incomplete. ### Do I need anything special to run UmaViewer on the English or Global game version? Yes. Set WorkMode to Default and Region to Global in the Other settings tab. Only the default work mode is supported, which means the game's own Download All button has to have been used so the data is present. ## Sources - [Issues](https://github.com/katboi01/UmaViewer/issues) - [katboi01/UmaViewer on GitHub](https://github.com/katboi01/UmaViewer) - [README](https://github.com/katboi01/UmaViewer/blob/master/README.md) - [Releases](https://github.com/katboi01/UmaViewer/releases) --- Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/katboi01-umaviewer