# STL Master — user reviews > 115 indexed App Store user reviews of STL Master by JA Logic Labs LLC, rated 4.20/5 from 49 ratings. - Source: https://appshunter.io/ios/app/stl-master/id1435885139/reviews - App overview in markdown: https://appshunter.io/ios/app/stl-master/id1435885139.md - Rating breakdown: 5★ 37 · 4★ 1 · 3★ 3 · 2★ 1 · 1★ 7 ## What do users think of STL Master? Overall sentiment: mixed **Pros** - 🚀 Fast and smooth rendering performance - 💰 Completely free with no ads or trackers - 🎨 High-quality rendering and visualization - 📱 Works well on mobile devices (iPhone, iPad) - 🌐 AR (Augmented Reality) feature - ☁️ Cloud file browsing integration - 🎬 Video recording capability - 🎨 Multiple material and gemstone color options - 📊 Measurement and dimension viewing - 📁 Support for multiple file formats (STL, OBJ) - 👥 Responsive developer support - 🖼️ Customizable background options - 💡 Multiple hidden features and capabilities **Cons** - 🐛 Frequent crashes and freezing - 🖱️ Difficult object manipulation and navigation - 🔍 Zoom limitations (hard to zoom out/in) - ❌ Inconsistent file loading and orientation - 🎨 Overly shiny/metallic default appearance - 🖥️ Poor Mac compatibility and functionality - 📍 No clear reference points for object centering - 🔘 Confusing and unintuitive UI/button design - 📏 Measurement display issues and reversed dimensions - 🚫 Markup mode is broken and inescapable - 💾 No save functionality for combined files - 📖 Lack of documentation and tutorials - 🎯 Missing basic Mac features (drag-and-drop, menu items) **Commonly reported bugs** - App crashes immediately on launch - Files won't open or load - Objects disappear when moved - Inconsistent file orientation on load - Markup mode traps user and requires app restart - Buttons don't toggle/close properly - Measurement dimensions display as mirror images - HDRI background doesn't affect model lighting - Freezing in editing/pen tip mode - Objects zoomed in with no zoom out capability - Parts of model cut off or not displayed - Mac version has significant stability issues - iOS 10.2 compatibility crash **Most requested features** - More color and material options - Unit measurement display and metric/standard conversion - How-to video tutorials for hidden features - Proper zoom in/out controls - Object positioning/movement button - Measurement and dimension tools - Drag-and-drop file opening support - Menu items for file operations - Closeable menu buttons - More file format support - HDRI lighting affecting model rendering - Save functionality for combined files - Proper markup mode functionality ## Newest reviews (14 of 115) ### 4/5 — Good STL Viewer *2026-03-01, version 5.2* I needed a way to view stl files and this does that and runs well on my phone. It has its quirks but I use it often. The dev could add more color options and turning the metal slider down has helped on certain models that look funny at first load. And it’s completely free, small, and no trackers or spying! ### 3/5 — A little rough but works *2025-09-27, version 1.0.5* First time I opened a file it wasn’t oriented right and I could not see most of it. Second time, it was centered in the viewport. Seems OK, just basic surfacing options. No menu items (like for Open File). Can’t drag and drop a file into the window to open it, or onto the icon. That is BASIC Mac functionality stuff. The “cloud” icon is for open, that doesn’t make sense. View buttons on the bottom don’t close their menus, you have to click in the window to hide them. OK, easy to try options, but clicking the button again doesn’t close them. No way to zoom in/out. ### 4/5 — Simple But Effective *2025-02-28, version 1.0.5* I like this, but my suggestion is to give the units the measurements are in. I assume it’s millimeters. Also, it may be worthwhile to give the ability to change units from metric to standard. ### 4/5 — Просьба устранить проблему *2025-02-03, version 5.2* При замене цвета модели, камней и все остальные открытые панели не закрываются, может их можно как то закрыть, очень мешают при записи экрана, спасибо разработчикам за такую программу :) ### 3/5 — Has potential but has many oddities *2024-10-22, version 5.2* I like this STL viewer but it needs a button to position (move object) the views. It can be difficult to adjust with fingers. The icons make little sense. The ruler icon shouldn’t be to make finish rough or smooth. Should be to measure things or show dimensions. The dimension screen needs to show measurements in a fix manner. Flipping the object around creates backward views of numbers. ### 3/5 — Difficult to Maneuver *2024-04-20, version 5.1.7* Doesn’t load completely every time. It’s hard to maneuver objects when they do load. No reference point for center. Very limited zoom out. And will freeze every time when in the editing mode (pen tip). ### 3/5 — Looks good but don’t go in the markup mode! *2023-12-27, version 5.1.7* If you go into the markup mode, you can’t get out, you can’t do any markups, and you have to exit the app. There also is no way to save if you combine stl files together. Looks good, but the functionality is poor. ### 3/5 — Amazing *2023-10-06, version 5.1.7* Is all good but I can’t modify any things. I need that since the mobile. I can change anything in the for example .stl ### 5/5 — It's fast‍‍​ *2023-04-04* This app needs some how-to videos since there are so many hidden features keeps coming up       ‍ ### 5/5 — It's fine ​ *2023-04-04* Being able to import new files to the scene is amazing feature  ​    ‌ ### 5/5 — Great app    ‌ *2023-04-04* I’m a new jewelry designer and had some flaws at my design for that reASŌn I wasn’t able to render it properly and keep getting error. I contacted the developer to address the issue if related about my design or the app itself, and he helped me out with my design issue. There were lots of open edges apparently. I am so glad to have good people here. ​ ### 3/5 — "Master" ist zuviel, aber es ist ein Viewer *2023-02-26, version 1.0.5* Wie es die Beschreibung anmuten lässt, können mit der App STL-Dateien geöffnet und angeschaut werden. Etwas störend ist die Tatsache, dass die Einstellungen (Hintergrundfarbe, etc.) bei jedem Neustart auf die Programmiereinstellungen zurückgesetzt werden. Da sollten die selbst gewählten Farben dauerhaft bleiben. Ansonsten ganz nett. ### 5/5 — Really nice *2023-02-02, version 5.1.6* Video recording with AR is beyond everything and makes me look so good to my clients and they think as if I’m showing off to them, but I’m not. This app is doing all the work by itself ### 5/5 — So good *2023-02-02, version 5.1.6* I was looking some app to show measurement view of the pieces I’ve done and now I found it I’m so glad ## Most critical reviews (10 lowest-rated) ### 1/5 — Doesn’t work *2026-01-21, version 5.2* Couldn’t get it to open any STLs unfortunately ### 1/5 — Terrible *2023-11-21, version 5.1.7* What a useless app. When I finally worked out how to load a file it just couldn’t be moved around without it disappearing out of the field of view. As far as measuring is concerned why does a 3D object only have 2 dimensions? It’s impossible to see what the labels refer to and they are usually mirror images. Uninstalled. ### 1/5 — Useless *2023-08-03, version 5.1.6* Cannot open STL files. Not sure what this is exists for ### 1/5 — Shiny. Too shiny *2023-03-25, version 5.1.6* I couldn't figure out how to turn off the glittery metallic colors. I just want a plain simple color. The glittery metallic was distracting and unusable. I found many color options but not all that glitters is gold. Looking for something else. ### 1/5 — "Master" Dass ich nicht lache *2022-11-06, version 1.0.5* Absolut schlecht gemacht. ### 1/5 — Absolutely dreadful *2021-10-25, version 5.0.5* This is a completely useless application, that does not show stl 3d models correctly. The objects are zoomed in and you cannot zoom out to see the whole model. Furthermore, parts of the model are cut out and not shown. Don’t bother!! ### 1/5 — Viewable but not useable *2019-08-12, version 1.2* Shows stl 3D files but as solid mass so fine detail is not viewable needs to have a light source to bring out details of files ### 1/5 — Crashes immediately *2019-02-25, version 1.1* Crashes immediately to home screen. Using iOS 10.2. ### 2/5 — Help *2025-01-11, version 5.2* I downloaded this app but when i try to use it, none of the buttons work. Wont do anything at all. Incan change color of brush but wont let me do anything with it? What am i doing wrong ? ### 2/5 — Love the look, but crashes when saving a photo *2024-03-27, version 1.0.5* As the title says, I want this to work well, so many good options. But it crashes when you try to save a photo. ## Most praised reviews (10 highest-rated) ### 5/5 — Превосходно! *2026-03-19, version 5.2* Функционально, удобно, бесплатно! Спасибо, высший балл! ### 5/5 — Спасибо за приложение! *2025-12-12, version 5.2* Оно и размеры показывает! Кроме того, можно подгружать другие STL-файлы! То-есть, если модель была автором разрезана и сохранена в отдельных файлах, просмотрщик может очень просто соединить обе половинки в единое целое! Ребята, ВЫ круты! Дальнейших Вам успехов! ### 5/5 — Отличный бесплатный просмоторщик STL *2025-02-18, version 5.2* Отличная программа! Бесплатна, без рекламы, все работает. Панели типа смена цвета и остальные убираются тапом по любому свободному месту на экране. Можно посмотреть габариты модели (ширину, высоту, глубину). Можно записать видео с экрана. Единственное — по умолчанию модель золотого глянцевого цвета, но цвет можно поменять, я ставлю серый и делаю его матовым. ### 5/5 — Great Idea *2025-02-04, version 1.0.5* Love the idea of this app, unfortunately it doesn’t work on Mac. Still gave it good ratings in hopes the developer considers working on the project again. If they could fix the crashes and add more colours, it would be an amazing Mac app ### 5/5 — Great app *2024-02-24, version 5.1.7* I love the app so far, there is just one bug. When you select the HDRI background, the lightning from the HDRI doesnt affect the model itself, you only get the HDRI background. The model itself is still lit by app default lightning setup. ### 5/5 — this is my life‍ ​‍‍ *2023-04-20* I thought this was only for jewelry designers and stuff but apparently I can open my large industrial designs as well at no cost, so cool!! ‍​ ### 5/5 — Fast   ‍ *2023-04-18* Well done for the 3D community, we appreciate your work and dedication  ‌​​ ### 5/5 — Nice  ‌  ​ *2023-04-18* Very nice background options also AR feature is my favorite    ‌ ### 5/5 — Thanks    ‌ *2023-04-18* Very reliable and gives lots of material options and gem stones when rendering multi piece designs ‍ ### 5/5 — So good     ‍ *2023-04-18* This app became our one and only rendering and sharing platform all in one app   ‍ --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-08.*