Week 12 Summaries
Exploring 3D Navigation:
Combining Speed-coupled Flying with Orbiting
Navigation technique used inside a 3D virtual environment is one of the important aspect for the success or failure of the system. The paper discusses about the existing navigation techniques and provides detailed information about one particular technique called ‘Speed-coupled Flying with Orbiting’.
Previous work in navigation techniques is quite vast and falls in two main categories: to understand cognitive principles behind navigation and point design technique for specific tasks and applications. Based on the previous research in 3D navigation a taxonomy is presented. The design of navigation, as per the taxonomy, is a task based model consisting of user goal, travel control and user interface metaphors. Each of these have their own subtasks.
There is a short discussion about the techniques that were considered. These are Object Manipulation and Ghost Copy: where the user manipulates multiple copies of an object, Inverse Fog/Scaling and Ephemeral World Compression: which is a combination of Inverse Fog technique, Inverse Scaling technique and World Compression technique, Possession and Rubberneck Navigation: where the user sees the world through the eyes of an object and is able to manipulate the new viewpoint effectively, Speed-coupled Flying with Orbiting: here the user’s navigation speed is coupled with the height at which he/she is flying. This is combined with orbiting technique where user essentially follows a circular orbit around the desired object.
Two user studies were also run with these techniques and the result showed that users performed better with Speed-coupled Flying with Orbiting and their performance enhanced with large displays. The future work mentioned refining the taxonomy and studying the effects of display devices on usability.
A Survey of Design Issues in Spatial Input
The paper discusses about the issues that normally occur while designing interactions within a 3D space. For this purpose they analyze and synthesize scattered results, observations and examples from previous studies into a common framework. The focus, in particular, is on spatial interaction techniques.
The authors have grouped the classification into two categories: Human perception and Ergonomic concerns. Some guidelines to keep in mind while designing with respect to human perception are providing spatial reference, considering between relative vs absolute gestures, single handed vs two handed interactions, providing multisensory feedback, understanding physical constraints and affordances for each mode of interaction, using head-tracking wherever necessary, restricting unnecessary degrees of freedom, using appropriate control metaphors, providing transparency wherever necessary, ray casting vs direct positioning, ray casting vs cone casting and recalibration of absolute global positions to a new logical position. Under ergonomics the designer should consider providing multiple degrees of freedom in coarse vs precise positioning, understanding the dynamics and working volume of user’s hand, understanding the affordances of multi-modal input, the mechanisms provided for clutching an object and understanding the importance of ergonomic details in spatial interfaces.
Finally the authors have extracted some important questions that should be asked while designing 3D interactions such as understanding which issues apply to spatial interfaces and which do not and why and is spatial technique prone to be task and user specific?
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