# ARPen vs TDMS

The clearest difference is update cadence: ARPen at every 4 months against TDMS's every 26 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.

ARPen ships an update every 4 months, TDMS every 26 months. The most recent releases landed on October 9, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | ARPen | TDMS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.5 (2 ratings)](https://appshunter.io/ios/app/arpen-mid-air-interactions/id1459493311/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 months** | Every 26 months |
| Monetization | Free | — |
| Size | 55 MB | 4 MB |
| Requires iOS | **14.2** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [RWTH Aachen University](https://appshunter.io/developer/371466796) | [TOHNICHI MFG.CO., LTD.](https://appshunter.io/developer/1609166229) |

## What reviewers say

### ARPen

[App page](https://appshunter.io/ios/app/arpen-mid-air-interactions/id1459493311)

Create 3D drawings and models in mid-air using a marker or a custom Bluetooth pen. Explore advanced geometry creation, object manipulation, and depth visualization. Export your creations as STL files.

**Highlights:** Draw freehand in mid-air, Create simple and complex geometries, Manipulate objects in 3D space, Explore depth visualization, Export models as STL files, Use marker or custom Bluetooth pen

**Features:** macOS Compatibility

**In-app purchases:** none


### TDMS

[App page](https://appshunter.io/ios/app/tdms/id6479276073)

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

**In-app purchases:** none


## Frequently asked questions

### Is ARPen free?

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

### Is TDMS free?

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

### Do ARPen or TDMS have ads?

Neither ARPen nor TDMS shows ads.

### Which is updated more often, ARPen or TDMS?

ARPen ships an update every 4 months, and TDMS every 26 months. Most recently, ARPen was updated on October 9, 2026 and TDMS on October 25, 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.*