**Abstract**

This chapter is dedicated to the description of 3D computer graphics used for the needs of virtual reality. Virtual reality (VR) is the use of computer technology to create a 3D virtual environment. The chapter presents some graphical features used in an environment as well as an explanation of good design practice. The chapter contains also the description of lighting settings, 3D objects/models and virtualization sequence, camera, and scenes where the wheelchair simulator is used as an example of the implementation environment.

**Keywords:** 3D graphics, 3D objects, virtual reality, web-based collaborative environments, lighting settings, object geometry, texturing

### **1. Introduction**

Technology is advancing in the directions in which it eases life. In the transport industry, it helps to get from point A to point B faster. In the education industry, it helps to obtain knowledge in a more effective way. In the health industry, it helps to operate or diagnose easier. Those are very few examples of how technology is simplifying life. The process of technology advancing is defined in a few steps. The first one is the curiosity about how things work. The second is the willingness to learn. The third is understanding and the fourth is experimenting. The creation of 3D computer graphics had a similar process. Firstly, there was a curiosity about how people see and percept the world. Secondly, it was a willingness to learn how the visual information from the outside world is getting into person. From that point, people realized that eyes were the ones to blame. Willingness to learn continued in this area and later on there was an understanding. The understanding of how the eyes work helped to create the first photographic camera. Lastly, there was experimenting in this field which led to the first photographs. As it is the nature of humans, we wanted to achieve more. We wanted to make those photographs to be animated and displayed somewhere. The development of this technology has gained rapid momentum. Soon, people were able to watch a short movie on canvas. With an introduction of the first computer, those two areas soonly merged. Before that, there was a need to represent data calculated on computer. Soon, it was represented on a simple display. As computers advanced and were more complex, there was a need to represent calculated data more effectively. Computer monitors were introduced and computer graphic was born. Before it

reached the possibility of 3D displaying, 2D scenes were presented. The most popular one was television. This is the greatest example so-called eye (visual) and computer content. As people realized how effective and entertaining computers can be, they started to wonder if we can simulate our world. Information from the computer area, eyes (visual) information and mathematics combined, and 3D computer graphics was born.

3D graphics opened a new world of experimenting in the area. As we live in a three-dimensional world, it gives us another level of possibilities of how to simulate and improve the virtual world-virtual reality. Representation of virtual reality via 3D technologies gives more authenticity and credibility. Virtual reality (VR) and related technologies are penetrating almost every aspect of our lives [1]. Nowadays, it is one of the most developing technologies that could significantly increase the level of interactivity [2]. This is greatly used in every industry. It has a great impact on health industry as it is possible to create projects like wheelchair simulators for people who are temporarily or permanently immobilized. Those people are provided with a number of courses to gain wheelchair skills but it is often financially unavailable. Virtual reality was proven as an effective tool for disabled people [3].

This chapter is dedicated to the description of 3D computer graphics used for the needs of virtual reality. The wheelchair simulator is used as an example of the implementation environment. Wheelchair simulator was built using web technologies via A-frame framework [4]. It is a simulation of a collaborative environment in VR (developed in authors' home laboratory LIRKIS at Department of Computers and Informatics, Technical University of Košice) where an immobilized patient should learn using an electric wheelchair. Guest can join the same 3D virtual environment and watch patient deal with the obstacles. Whole simulator contains multiple scenes with different obstacles. The pilot project was also implemented in a unique 3D virtual LIRKIS CAVE environment (**Figure 1**).

**Figure 1.** *Patient on wheelchair in 3D virtual LIRKIS CAVE environment.*
