@MASTERSTHESIS{ 2017:461460899,
 	title = {Usage of tactile feedback to aid cooperative object manipulation in virtual environments},
 	year = {2017},
 	url = "http://tede2.pucrs.br/tede2/handle/tede/8235",
 	abstract = "Virtual reality is a technology that allows users to view and interact with a 3D virtual environment (VE) in real time. A collaborative virtual environment (CVE) is a type of VE that allows two or more users to be in the same virtual environment together. Collaborative virtual environments have some issues that simple VEs do not have. For example, different techniques are required in order to allow two users to manipulate (move or rotate) a virtual object together. Some of these techniques can lead users to do unnatural movements.
 This study evaluates haptic feedback to let users aware of wrong movements during a cooperative object manipulation. The SkeweR technique was used as a testbed. This technique is based on the use of crushing points, where the users grab the object for the first time, to simultaneously move/rotate an object. Once the users have their hands positioned on the crushing point during the object manipulation, the interaction becomes more natural, in the sense that it is more similar to the real process. However, due to the lack of any physical constraint to the users’ movements, it is often noticed that the users’ hands move away from the crushing point during the interaction. To solve this problem, this work proposes the usage of tactile feedback to inform the user about the distance between his hand and the crushing point. The tactile feedback is provided by a vibration micromotor attached to the user’s thumb. To validate the method, a user study based on the 3D manipulation of a virtual object was performed. The virtual object had to be translated and rotated through a virtual path along a virtual wire, from the beginning to the end of it.
 During the interaction, users manipulated a three degrees of freedom (3DOF) position tracker and were requested to keep this tracker in the same position of the crushing point. During the trials, the participants used three modalities of interaction: without any feedback, with a visual feedback and with tactile feedback. Results showed that the users do more natural manipulations when using tactile feedback.",
 	publisher = {Pontifícia Universidade Católica do Rio Grande do Sul},
 	scholl = {Programa de Pós-Graduação em Ciência da Computação},
 	note = {Escola Politécnica}
}