Virtual environments are used in very diverse applications: from leisure games to professional training and rehabilitation systems. In these applications, users interact with the elements of the environments through avatars in order to perform virtually actions such as picking objects, carrying and dropping them, and more complex manipulations tasks such as cutting and drilling in surgery training, shooting and punching in actions games, and cooking and cleaning in life simulation games and neuropsychological rehabilitation. To launch these actions, users must first select the objects with which they want to interact by pointing on them and confirming the selection by clicking a button or a key. This process is usually defined as point-and-click and more shortly pointing. Pointing is an essential feature of interaction in virtual environments, and it is relevant to measure its usability. Besides, pointing in 3D environments has a lot of similarities with pointing in 2D graphical interfaces. Fitts's law relates the efficacy of pointing with the distance to the target and the target's width. The efficacy is also affected by the density of the environment and its level of occlusion. The influence of these factors has been studied in various papers to propose different types of pointing mechanisms. In this report we classify and survey these techniques.