# 3D PDF Viewer vs The Engine

The clearest difference is update cadence: The Engine at every 2 weeks against 3D PDF Viewer's every 10 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

3D PDF Viewer ships an update every 10 months, The Engine every 2 weeks. The most recent releases landed on October 1, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | 3D PDF Viewer | The Engine |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[1.5 (2 ratings)](https://appshunter.io/ios/app/3d-pdf-viewer/id919857557/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 10 months | **Every 2 weeks** |
| Monetization | Free | — |
| Size | 21 MB | 48 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [ProtoTech Solutions and Services Pvt. Ltd.](https://appshunter.io/developer/365252924) | [Nicolas Perry](https://appshunter.io/developer/6776960102) |

## What reviewers say

### 3D PDF Viewer

[App page](https://appshunter.io/ios/app/3d-pdf-viewer/id919857557)

View and interact with 3D models embedded in PDF files on your mobile device. Easily zoom, pan, and rotate models using intuitive multi-touch gestures. Load files directly from cloud storage services like Dropbox and Google Drive.

**Highlights:** 3D PDF model rendering (.prc), Multi-touch gestures (zoom, pan, rotate), Import from cloud storage, Open password-protected PDFs, Integrated Box and Dropbox browsing, Supports meshes and colors

**In-app purchases:** none


### The Engine

[App page](https://appshunter.io/ios/app/the-engine/id6776960100)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is 3D PDF Viewer free?

3D PDF Viewer is free to download, with no in-app purchases.

### Is The Engine free?

The Engine is free to download, with no in-app purchases.

### Do 3D PDF Viewer or The Engine have ads?

Neither 3D PDF Viewer nor The Engine shows ads.

### Which is updated more often, 3D PDF Viewer or The Engine?

3D PDF Viewer ships an update every 10 months, and The Engine every 2 weeks. Most recently, 3D PDF Viewer was updated on October 1, 2026 and The Engine on October 6, 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.*