**4.2 Augmented reality software development kit**

Augmented reality software development kits (AR SDK) have fundamental features such as image, object and location recognition, position estimation and others. Among the popular AR SDKs are ARKit, ARCore, Vuforia Engine, Wikitude AR SDK, Kudan, AR SDK, EasyAR SDK and ARToolKit. They all allow 2D image recognition and are compatible with different platforms (iOS, Android, Windows and others). Some of them provide 3D object recognition features, while others help create geolocation applications. AR SDKs can be used to create augmented reality applications for smartphones, tablets and a variety of wearable devices. This approach results in developing stand-alone applications that users use to view virtual content that augments and enriches real objects.

**Figure 5.** *Wikitude studio project.*

**Figure 6.** *Virtual buttons in BookStatistica application.*

Augmented reality applications, created with AR SDKs, are interactive, are feature-rich and embody the best of augmented reality technology. Their development is a complex and time-consuming process, requiring programming skills.

**Figure 6** shows an augmented reality application BookStatistica, developed with Unity and Vuforia Engine. After scanning different markers, virtual buttons appear on the device screen. Learners can make a choice between different options-for example, video materials that show how statistical methods are done in different statistical packages.
