HoloSketch: a virtual reality sketching/animation tool

COMMENT
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SUMMARY
This paper describes HoloSketch, a virtual reality-based 3D geometry creation and manipulation tool. It uses a head-tracked stereo shutter glasses and a desktop CRT display. The system allows users to create virtual objects (and view the results in real time stereoscopically) with a 3D wand manipulator directly in front of the user, at very high accuracy. For every frame rendered for each eye a viewing matrix is calculated using the information from head tracker. The authors claim that the system is very accurate (compared to existing VR technologies at that time) with an error of +-0.25cm in world coordinates.
Menu Design: It is a fade up menu which appears when the right wand button is pressed. The menu is organized as a 3D pie menu and appears to be right in front of the wand pointer. To select user pokes the want tip at the desired button. The menu also supports sub menus. A sub menu appears in the front pushing back the main menu in space.
Features:
1. HoloSketch supports many drawing primitives like rectangular solids, spheres, ellipsoids etc. Other types of drawings involve 'sweeping' across the space and putting drawing material. The drawing material can be wireframe lines, toothpaste etc. In addition to creating new geometry, new geometries can be imported from other modelling environments.
2. Color selection can be done using a color cube.
3. An object can be selected by pressing the middle want button over it. A rubber band selection is also available for group selection.
4. Editing operations like translation, scaling, grouping of objects, rotation, animation are supported.
5. Viewing Control: The viewer can look around objects by moving his head. The viewer can also move/rotate the entire virtual universe. The viewer can also move through the virtual universe.
Results: To test their system he authors engaged an artist (having no prior experience with holosketch but experience with tradition 3d modelling systems) for a month of trails using their system. They found that it was very quick and easy to create complex forms using holosketch. They also fund that it was difficult to make fine adjustments holding ones hands in air. To remedy this the 10X reduction mode was used. In future author would like to expand the study to test for novice users. The author also plans to improve and extend the animation controls.

DISCUSSION
This seems to be a seminal paper in stereoscopic 3d modelling given that it was published in 1995. The menu design seems to be intuitive and useful for selecting in 3D. The idea that we can look around objects and move in the 3D virtual universe seems very interesting. I would have loved to see a user study involving novice users and their feedback. The authors plan to do that in future.