# Augmented Reality as a Didactic Resource for Teaching Mathematics
## 2 Materials and Methods  
One of the most widely used technology resources in math classrooms is GeoGebra. It has many advantages: it is free, its use is very intuitive, and there is a vast amount of resources developed by teachers and available to anyone. However, we decided not to use GeoGebra in our project for technical reasons.  
Geogebra uses Google's augmented reality library (ARCore, it is a software development kit developed by Google (Google LLC, California, USA) to built AR apps) to implement augmented reality. To use ARCore you need to have a fairly new and expensive mobile phone. Mobile phones and tablets before certain dates do not support ARCore and therefore you cannot use augmented reality with Geogebra (it does not work even if you update to new versions of Android). In addition, not all new mobile phones use Android, so in principle you will not be able to use ARCore.  
In this project, the development of AR teaching resources will be carried out using Unity software. The reason for this choice is mainly because it is a very powerful and versatile tool that allows the creation of different types of applications.  
Using Unity we can create applications for any platform without problems. Today, videogame design engines are the best to design AR experiences. Moreover, something very important for us, being coherent and realistic with the Spanish public educational system, is to design resources in AR which can be applied without having very expensive hardware, but rather something in a mid-range, available to students and teachers.  
Unity is the most popular game development software among developers around the world (about half of the videogames that are designed are made using this tool). It creates applications and designs AR experiences for all types of platforms such as mobile phones, consoles, or personal computers. The company that provides this software is Unity Technologies, which is based in San Francisco. It was founded in 2004 by [PERSON], [PERSON], and [PERSON] in Copenhagen (originally under the name Over the Edge Entertainment and changed its name to Unity Technologies in 2007).  
The huge community of Unity users is very active in forums, where there is a solution for many of the questions and doubts that may arise during its use. In addition, on the official Unity website [33], questions about programming, examples, and mini tutorials can be consulted.  
Vuforia is a software development kit (SDK) to create AR applications. It uses a series of computational algorithms that allows applications to recognize different types of markers (also called \"ImageTarget\") in two (for example, a QR code) and three dimensions (real-world objects) in real time. When the marker is recognized by the application thanks to Vuforia, accurate digital information is shown to the user. This ability to recognize images allows positioning and orientation of predesigned virtual objects (3D models) and other information in relation to real images that are captured by the device's camera. In addition, if the information shown is a digital model in two or three dimensions, the digital object will \"detect\" the position and orientation of the ImageTarget in real time, so that if we move the marker, the virtual object will move synchronized with it. This effect makes the user have the impression that the virtual model is an object present in the real world, even if it is not really.  
Vuforia allows the implementation of AR on Android and iOS (by Apple) and the creation of AR applications on Unity (easily exportable to any platform). Therefore, with Unity and Vuforia augmented reality applications can be created for almost any system. That is why both have been chosen to develop this project.