We present a new Virtual Reality (VR) interaction technique, called Cursor On Surface (CrOS). It is an interaction technique for cursor manipulation on 2-manifolds using touch screen input. The objective is to provide a technique to easily perform complex modelling operations in VR. CrOS is based on an algorithm which maps 2-D inputs into cursor displacements on 3-D surfaces. The technique relies on two principles. Firstly, it restricts the manipulation space to a 2-D space. Secondly, it reduces the complexity of the task through an automatic orientation algorithm that prevent the user from switching between edition task and object repositioning task.

The use of Touch Screen Interaction (TSI) for 3-D interaction entails both the addition of new haptic cues and the separation of the manipulation of the Degrees of Freedom (DoF) of the task: a 3 DoF task must be transformed into a 2-D+1-D task to be completed using a touch screen. In this paper, we investigate the impact of these two factors in the context of a 3-D positioning task. Our goal is to identify their respective influence on subjective preferences and performance measurements. To that purpose, we conducted an experimental comparison of five positioning techniques, isolating the influence of each of these two factors. The results we obtained suggest that the addition of haptic cues does not influence the user precision. However, the decomposition of the task has a strong influence on accuracy. More precisely, separating the manipulation of the depth dimension leads to an increased precision while isolating other dimensions does not influence the results. To explain this result, we realised a behavioural analysis of the data. This study suggests that the differences in the performance may be linked to the perceptual structure of the techniques. A technique isolating the manipulation of the depth seems to have a more adapted perceptual structure than a technique separating the height, even if those two dimensions are equally involved in the realisation of the task.

In this paper we present a new interaction technique based on degrees of freedom (DoF) decomposition for accurate positioning in virtual reality environments. This technique (called DIOD for Decomposition and Integration Of Degrees of freedom) is based on an adaptation of the Two-Component Model. It provides two different control levels regarding DoF coordination, one integrating and one separating the manipulation of the DoF. Our hypothesis is that each control level is appropriated to a different phase of the positioning task. During the ballistic phase, users manipulate all the dimensions of the task at the same time. However, during the control phase, users try to manipulate specific dimensions individually. The results of a preliminary study we conducted seem to indicate that the DIOD technique is more efficient than existing techniques.

In this paper we investigate the influence of the integration and separation of the Degrees Of Freedom (DOF) on the users' performances during 3-D orientation tasks. For this purpose, we compare the performances and the level of DOF's coordination users reached using two interaction techniques, one integrating and the other separating the task's DOF. To evaluate the degree of coordination, we propose a new behavioural measurement (called Magnitude of Degrees of Freedom's Separation), which provides the number of DOF simultaneously manipulated during an orientation task. The results of our study suggest that users are not able to integrate the manipulation of all the DOF during the whole task even using a direct manipulation technique. Moreover, if the interaction eases the task's decomposition, its use can lead to significant improvements regarding the achievement times. This result suggests that the simultaneous manipulation of all the DOF does not necessary lead to the best performances.