This paper, considering the technology of 1995 when, it was published presented a nice method of augmenting the 2D drawing to the 3D. Users manipulate the virtual world, which they see using in the big CRT monitor by using a hand held mouse like device, which authors call wand. This wand has 3 top buttons and one side button along with a protruding road which acts like a cursor. To keep the objects in the virtual world look close to the naturally viewed objects, computer calculates a new viewing matrix separately for each eye and the refreshing rate is kept close to at least 13 Hz. This ensures that high resolution close to reality image is observed in the virtual world.
In their effort to extend the 2D menus to the 3D in the virtual world, certain modifications had to be made to prevent occlusion and also to take care of the Fitt’s law in 3D as in 3D wand has to move more distance in 3D compared to one in the 2D.So in order to cope up with the problems, authors proposed another way of using huge pop menu with fade up menus to give way to other menus .All this is manipulated using the wand.
Holosketch has lot of features to explore by the users. There is a drawing mode in which users cab draw objects like cylinder, cones, rings etc and even create another instance of it using the left button and keeping that button pressed, object can be manipulated in the 3D space.Object for edition can be selected by placing the wand tip on it and pressing the middle button to select the object for edition. To support the movement in 3D much intuitive, they have supported the side button to present the grasp like feeling to the user and then working with the object in 3D. In order to prevent the accidental pressing of the button by the user, it is necessary that the user presses simultaneously the additional key board keys. The Holo-sketch supports three movements: rotational, orientation, rotation + orientation. They are also bound to the designated key board keys. Authors have highlighted the need to take care of the jitters and noise addition because of them and proposed a use of some kind of 10X reduction mode which provides finer control. The interesting part of the Holo-sketch is elementary animation like rotation, angle, movement between positions, scaling and oscillations.
Discussion:
This paper presents a nice method to sketch in 3D and also add some animation to the creations. It is interesting that the system gives close to real-time observation as system is calculating matrix for each head movement. I believe with 1995 hardware, it is indeed a good step, however use of the CRT monitor doesn’t address to the usage of the system in the real world scenarios. Usage of virtual 3D projection technology along with augmented reality glasses would be a nice addition to the interface. Also, I believe there should be a kind of erase mode where user can erase a small part of the sketch in 3D as it will be challenging to do so in 3D considering occlusion cases. Also in this paper I wondered what is the 10x mode? There is actually no reference for that. However, I believe, for a device like wand, taking care of jitters was really a good approach though, I was unable to understand it.
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