# EnginoRobot BT (Controller) vs Merge Object Viewer

The clearest difference is in-app purchases: EnginoRobot BT (Controller) at none against Merge Object Viewer's 4. EnginoRobot BT (Controller) also leads on iOS requirement (12.0 vs 15.0). Merge Object Viewer's advantage is update cadence (monthly vs every 4 months). On price, ads and device support there is nothing between them.

Both are free to download. Merge Object Viewer sells 4 in-app purchases, starting at $9.99 per month. EnginoRobot BT (Controller) asks for nothing beyond the download.

EnginoRobot BT (Controller) ships an update every 4 months, Merge Object Viewer monthly. The most recent releases landed on May 17, 2026 and August 12, 2026 respectively.

## The numbers

| Metric | EnginoRobot BT (Controller) | Merge Object Viewer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.5 (390 ratings)](https://appshunter.io/ios/app/merge-object-viewer/id1367544362/reviews)** |
| Number of ratings | — | **390** |
| Positive reviews | — | 48.1% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Monthly** |
| Monetization | — | Free with in-app purchases |
| Size | 50 MB | 414 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [ENGINO TOY SYSTEMS LIMITED](https://appshunter.io/developer/875789415) | [Merge Apps](https://appshunter.io/developer/1253049593) |

## What reviewers say

### EnginoRobot BT (Controller)

[App page](https://appshunter.io/ios/app/enginorobot-bt-controller/id1067244128)

**Features:** macOS Compatibility

**In-app purchases:** none


### Merge Object Viewer

[App page](https://appshunter.io/ios/app/merge-object-viewer/id1367544362)

Explore hundreds of 3D digital teaching aids with this app. Students can interact with models of rocks, mammals, cells, and more. The app also allows users to upload and view their own 3D objects on a compatible device.

**Highlights:** Hundreds of 3D teaching aids, Interactive 3D models, Learn about science and biology, Upload and view custom 3D objects, Hands-on digital learning

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Object Viewer Premium Monthly | $9.99 | per month |
| Merge EDU Individual | $9.99 | per month |
| Object Viewer Premium Annual | $99.99 | per year |
| Merge EDU Individual | $99.99 | per year |

**What reviewers like**

- 🚀 Engaging AR STEM tool
- 👍 Intuitive interface
- 👍 Seamless object merging
- 👍 Extensive file format support
- 👍 Convenient sharing options

**What reviewers complain about**

- 🐛 Frequent crashes
- 🐛 Slow rendering/loading
- 🐛 Compatibility issues on older devices
- 🔒 Paywall for full access
- 🐛 Unstable login/account management

**Reported bugs**

- Objects not loading or displaying incorrectly
- App freezing or closing unexpectedly
- Labeling/annotation issues with 3D objects
- Compatibility problems on iPads and older iOS versions

**Requested features**

- Adjustable lighting for 3D objects
- Ability to snap objects together
- Camera button for capturing scenes
- Restore VR support
- More free 3D content options


## Frequently asked questions

### Is EnginoRobot BT (Controller) free?

EnginoRobot BT (Controller) is free to download, with no in-app purchases.

### Is Merge Object Viewer free?

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

### Do EnginoRobot BT (Controller) or Merge Object Viewer have ads?

Neither EnginoRobot BT (Controller) nor Merge Object Viewer shows ads.

### Which is updated more often, EnginoRobot BT (Controller) or Merge Object Viewer?

EnginoRobot BT (Controller) ships an update every 4 months, and Merge Object Viewer monthly. Most recently, EnginoRobot BT (Controller) was updated on May 17, 2026 and Merge Object Viewer on August 12, 2026.

---

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