Deering, Michael F. HoloSketch: A Virtual Reality Sketching/Animation Tool. (1995) ACM Transactions on Computer-Human Interaction.
Summary:
Deering's 3D VR system, HoloSketch, aimed to allow the creation of three-dimensional objects in a virtual reality environment. Users donned VR goggles with a supercool 960x680 20'' CRT monitor and interacted with the virtual world via a six-axis wand. The head-tracking goggles allow the user to look around images hovering in front of them.
HoloSketch prides itself in displaying stable images that do not "float" or "swim" as the user moves their head. They accomplish this by having a highly accurate absolute orientation tracker in the goggles. The use of a flat-screen CRT also helps, as well as program corrections for interocular distances.
A good chunk of the paper focused on user interactions, such as menu navigation. Deering's system uses a 3D pie (radial) menu that can be activated by holding down the right click on the wand. The user can then navigate the menu while holding the button and "poke" the menu to activate submenus and items. To create and draw objects, the user first selects a primitive from the menu and then places the primitive by hitting a button on the wand. The user can then rotate, size, and position the object using a combination of wand-waving and keyboard buttons.
Users can also create animations with the system. Some animations require still shots of slightly altered objects that can be grouped temporally (like a VR flipbook). Other animations can be added to objects or groups, such as a rotor property or blinking colors.
An artist tested the system for a month and provided feedback. Overall the artist found the tool easy to work with after a few days, although some of the features available in other applications were missing from HoloSketch. One issue that Deering noticed was the lack of a user's head movement when trying to view the object; users are too used to stable heads that examining an object from different angles was not intuitive.
Discussion:
HoloSketch seems like an interesting application and provides a variety of ideas, some which I believe are beneficial, while others are not. The "poking" of menus seems intuitive, and if the system has a high absolute accuracy this should work well. Yet, Deering mentioned how user's arms can get tired and are unstable, and supporting an arm and wrist is out of the question when you try to make an environment natural. Instead HoloSketch had some button that reduced the jitter somehow when activated, which seems like a hack that allows for a quick fix of a potentially serious issue with using the system.
I also understand why people would not want to constantly move their head around the display. If the display was on a round table this would be a non-issue, but constantly moving around in a chair and leaning different directions is a strain to a user. Furthermore, the 20" CRT is not that large of a screen the the user would be able to "see" all around the object; I would have liked to know the actual viewing angle.
Overall, though, I liked the system and the paper itself was well-written and gave a good overview of the features.
4 comments:
yeah i agree the head moving issue is a bit strange to me. what happens if i was modeling a person and want to modify the back of the person's head? how do i move my head so that i can see the back part of the model's head? do i look behind my computer screen? there should probably be another way to control the camera view other than the own user's head movements.
The head tracking --> angle of view usability question is an interesting problem. I guess I can see this being potentially useful if used in conjunction with an ability to rotate the scene with a gesture or button -- maybe you could "hold" and object with one hand and look at slightly different angles using both head and hand movement together -- but it could be easily more trouble than it's worth if the scene shifts when the user randomly stretches or shifts position to be more comfortable in the chair.
Yeah, head movement is not exactly the best choice to move around the environment to engage in 3D sketching. Brandon and Katie brought up excellent points concerning the matter, so there's not much I could contribute. I do have to say that it would be more ideal to have something that would be analogous to having virtual sculptor capabilities instead of using head tracking.
You could do something like grab with the wand and then rotate on the three axes. Also remember this was done in the 90s, so the tech was a little immature.
Post a Comment