Paper Reading #10: A screen-space formulation for 2D and 3D direct manipulation

Title:
A screen-space formulation for 2D and 3D direct manipulation


Conference:
Cindy Skach
Felipe Othick

Reference:
Reisman, J., Davidson, P., Han, J.  A screen-space formulation for 2D and 3D direct manipulation.  UIST '09.  http://delivery.acm.org/10.1145/1630000/1622190/p69-reisman.pdf?key1=1622190&key2=4113797921&coll=DL&dl=ACM&ip=165.91.15.192&CFID=9231901&CFTOKEN=19689043

Summary:
This paper explores the area of the shift from 2D to 3D Rotate-Scale-Translate (RST).  RST is the idea that one can do these three aspects.  Current models involve using fingers on devices such as the iPad in order to manipulate the display.  In 2D manipulation, there are informal standards that are applied when using RST, but since 3D manipulation is rare, there are no standards for its use.  The researchers set out to explore possibilities of understanding 3D RST.

Some current implementations of visualizing 3D surfaces involve rotating a 3D space about a fixed axis.  This requires about the same techniques involved in 2D manipulation, however limits the scope to which one can manipulate an environment as it only uses 4 Degrees of Freedom (DOF) when there is a possible 6..  Another such constraint is the use of a physics engine where physics regulates the actions you can do within a 3D space.  Both of these attempts are limited.

In an attempt to overcome these current interaction constraints, the paper shows many calculations which are meant to implore a system in which 6 DOF will be possible.  The rest of the paper describes the system they built.

The researchers tested their design against the current 4 DOF systems by putting constraints on their own system in order to simulate the 4 DOF.  According to them, there were no differences between these systems.  Upon testing their system in 6 DOF, using finger interaction they noticed that the motions were not immediately clear to them as how to interact with their system.  They developed tools in the form as hand positions to interact.  They first used a two-handed three-finger implementation.  This they labeled as the "swivel interaction".  The swivel interaction allows the user to pin the object to an axis with one hand (two fingers) and with the other finger rotate around that axis.  They also show a two-handed four-finger interaction.  This because of the arm and wrist movement needed was awkward but enabled a greater deal of variability in the actions one could perform.

They enhanced the system based upon their initial tests which included biasing calculations based upon finger placement in order to disambiguate close finger proximity.  They also added a swirl function in which the three-finger implementation could be used to calculate the initial motion with the free finger and if it then moved along a different axis to rotate accordingly.  They also worked with putting in penalties, or manufactured constraints in order to perform specific actions in certain situations.  This allowed user interaction to map in a simpler way, but did limit actions.

Future goals are to explore ways to make the interactions more predictable with as little intervention (penalties) as possible.

Discussion:
Aside from going into math that I was not about to follow, this paper provided a basis in which I feel I have a good understanding of not only their goals but also their outcome which is better than the other paper from this conference I read.  I like the idea of interacting with 3D places.  It reminds me of seeing holograms on movies and how they interact with them.  It would be awesome if that's what technology was moving towards.  Based upon this presentation I appreciate their correction in order to make things simpler rather than simply leaving it the way it is because of some "superior mathematics".  I would like to see if 3D space interactions such as this is ported to things like the iPod Touch.  I have seen some 3D engines running on it, but it was more a console way of interacting with the space.