# STL Simple Viewer vs AI Viewer

The clearest difference is rating: STL Simple Viewer at 4.3 against AI Viewer's 2.9. STL Simple Viewer also leads on ratings volume (909 vs 14). AI Viewer's advantage is update cadence (fortnightly vs every 5 months) and review sentiment (29% vs 18%). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. STL Simple Viewer sells 4 in-app purchases, starting at $0.99 per 7 days and AI Viewer sells 1 in-app purchase, starting at $24.99 per year. Whichever you choose, the download price is not the number that matters.

STL Simple Viewer holds the better App Store score, 4.3 against 2.9. That said, the two scores are not equally well evidenced: STL Simple Viewer has 909 ratings behind it against 14, so its average is the more settled of the two. Written reviews complicate that: 18% of STL Simple Viewer's written reviews are positive against 29% of AI Viewer's, so the app with the better star average is not the one people write more warmly about.

STL Simple Viewer ships an update every 5 months, AI Viewer fortnightly. The most recent releases landed on October 21, 2026 and September 21, 2026 respectively.

## The numbers

| Metric | STL Simple Viewer | AI Viewer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.3 (909 ratings)](https://appshunter.io/ios/app/stl-simple-viewer/id1493598400/reviews)** | [2.9 (14 ratings)](https://appshunter.io/ios/app/ai-viewer/id1505083223/reviews) |
| Number of ratings | **909** | 14 |
| Positive reviews | 18.1% of reviews | **28.6% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | Yes | Yes |
| Update frequency | Every 5 months | **Fortnightly** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 19 MB | 19 MB |
| Requires iOS | 17.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Victor Bovio](https://appshunter.io/developer/327627515) | [Vaibhav Singhal](https://appshunter.io/developer/1719416463) |

## What reviewers say

### STL Simple Viewer

[App page](https://appshunter.io/ios/app/stl-simple-viewer/id1493598400)

Easily view and interact with 3D STL CAD models. Supports various file types and offers advanced rendering options for detailed analysis. Get model information and explore interiors with clipping planes.

**Highlights:** View ASCII and Binary STL files, Load STL from ZIP, Rotate, pan, and zoom, Orthogonal and Perspective modes, Model info (triangle count, bounding box), Rendering options (faces, edges, transparency), Clipping plane for interiors

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro version (1 week plan) | $0.99 | per 7 days |
| Pro version (1 month plan) | $1.99 | per month |
| Remove Ads | $2.99 | one-time |
| Export Pack | $3.99 | one-time |

**What reviewers like**

- 🚀 Simple and intuitive viewer
- 👍 Useful viewing options
- 💡 Supports multiple file formats

**What reviewers complain about**

- 🐛 Frequent crashes
- 🔋 High battery consumption
- 🚨 Excessive and intrusive ads
- 🔍 Limited functionality for larger files

**Reported bugs**

- App crashes when opening larger STL files
- Inability to open some file formats
- Ads continue to appear even after paying for ad removal

**Requested features**

- Add ability to save color/lighting settings
- Improve stability and reduce crashes
- Provide an ad-free paid version


### AI Viewer

[App page](https://appshunter.io/ios/app/ai-viewer/id1505083223)

View Adobe Illustrator (.ai) files on your mobile device without needing a license. Convert .ai files to PDF or PNG, zoom in on previews, and easily locate Illustrator files stored on your device.

**Highlights:** Preview .ai files, Save as PDF or PNG, List all .ai files on device, Pinch to zoom, Remove ads permanently, Contact support

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Yearly Subscription | $24.99 | per year |


## Frequently asked questions

### Is STL Simple Viewer free?

STL Simple Viewer is free to download, with in-app purchases available.

### Is AI Viewer free?

AI Viewer is free to download, with in-app purchases available.

### Which has better reviews, STL Simple Viewer or AI Viewer?

STL Simple Viewer is rated higher. STL Simple Viewer averages 4.3 out of 5 from 909 ratings, while AI Viewer averages 2.9 from 14 ratings.

### Do STL Simple Viewer or AI Viewer have ads?

Both STL Simple Viewer and AI Viewer show ads.

### Which is updated more often, STL Simple Viewer or AI Viewer?

STL Simple Viewer ships an update every 5 months, and AI Viewer fortnightly. Most recently, STL Simple Viewer was updated on October 21, 2026 and AI Viewer on September 21, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*