Submitted by PPG Ci?ncia da Computa??o (ppgcc@pucrs.br) on 2018-07-26T19:57:26Z No. of bitstreams: 1 THOMAS VOLPATO DE OLIVEIRA_DIS.pdf: 2340160 bytes, checksum: a77fc7c024da22cb1ea18eec69501d7e (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-08-02T12:22:16Z (GMT) No. of bitstreams: 1 THOMAS VOLPATO DE OLIVEIRA_DIS.pdf: 2340160 bytes, checksum: a77fc7c024da22cb1ea18eec69501d7e (MD5) / Made available in DSpace on 2018-08-02T12:38:03Z (GMT). No. of bitstreams: 1 THOMAS VOLPATO DE OLIVEIRA_DIS.pdf: 2340160 bytes, checksum: a77fc7c024da22cb1ea18eec69501d7e (MD5) Previous issue date: 2017-08-23 / Realidade virtual ? uma tecnologia que permite aos seus usu?rios visualizar e interagir com ambientes virtuais (AV) 3D em tempo real. Um ambiente virtual colaborativo (AVC) ? um tipo de AV que permite que dois ou mais usu?rios estejam juntos no mesmo ambiente virtual. Ambientes virtuais colaborativos t?m algumas dificuldades que AV comuns n?o t?m. Por exemplo, diferentes t?cnicas s?o necess?rias a fim de permitir a dois usu?rios a manipula??o (mover ou girar) conjunta de um objeto virtual. Algumas dessas t?cnicas podem levar os usu?rios a realizarem movimentos n?o naturais. Este trabalho avalia o retorno h?ptico para deixar os usu?rios cientes de movimentos errados durante a manipula??o colaborativa de objetos. A t?cnica SkeweR foi utilizada como teste. Esta t?cnica ? baseada em crushing points, onde os usu?rios pegam o objeto pela primeira vez para simultaneamente mover e girar o objeto. Uma vez que os usu?rios mant?m a posi??o da m?o sobre o crushing point durante a manipula??o do objeto, a intera??o se torna mais natural, no sentido de que se torna mais similar ao processo real de segurar um objeto. Entretanto, devido ? falta de restri??es f?sicas de movimento, frequentemente, durante a intera??o, a m?o do usu?rio se move para fora do crushing point. Para solucionar este problema, este trabalho prop?e o uso de retorno t?til para informar os usu?rios sobre a dist?ncia entre a posi??o da m?o e o crushing point. O retorno t?til ? fornecido por um minimotor de vibra??o preso no polegar do usu?rio. Para validar o m?todo, fez-se um estudo com usu?rios em que estes deveriam realizar a manipula??o 3D de um objeto virtual. Este objeto precisava ser transladado e girado atrav?s de um caminho virtual ao longo de um fio virtual, do in?cio deste at? o fim. Durante a intera??o, os usu?rios manipularam um rastreador de posi??o com tr?s graus de liberdade (3DOF) e deveriam manter a posi??o do rastreador na mesma posi??o do crushing point. Durante as rodadas do experimento, os participantes testaram tr?s modalidades de intera??o: sem nenhum retorno, com retorno visual e com retorno t?til. O resultado dos testes mostrou que usu?rios realizaram manipula??es mais naturais quando estavam usando o retorno t?til. / 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.