Extending 2D object Arrangement with Pressure-Sensitive Layering Cues (UIST-2008)

Extending 2D object Arrangement with Pressure-Sensitive Layering Cues (UIST-2008)

By: Philip L. Davidson, Jefferson Y. Han

Summary:
This paper discusses a pressure-sensitive depth sorting technique on 2D objects with multitouch or multipoint controls. The direct manipulation of objects encourages the grouping of objects, especially when Rotating, Scaling or Translating them. It presents two novel techniques for 2D layering by using a stack of selected objects as well as using a drag and drop model. The first thing that this paper discusses is the multiple studies that have been done which show that a humans estimation of pressure is often bad and is more appropriate as a rate control. It has been shown that humans can get better pressure control with visual feedback at the point of contact as well. A tilt calculation was also performed while the Rotation, Translation and Scaling (RST) calculations were being calculated depending on the pressure that was applied. This system uses a directed acyclic graph of tests which can show intersections to detect overlapping layers. A combination of rendering cues are used to show the tilt to the user by showing “out of plane” will alter the visible outline of the object being altered. Element to element layering was discovered to be useful only when the edges of the objects could be seen, but as they become more complex it became less useful. For future work, they talked about inserting prior overlap relationships into the DAG as lower priority constraints. They also suggested allowing the user to freeze the layering relationships for groups of elements regardless of their overlap state.

Discussion:
To be honest this paper was a little confusing and not very much interesting for me. I understood what they were trying to do, but they seemed to jump around a bit with how they talked about things. It seemed to go from topic to topic with no real linking of anything between them. I felt like if I took individual parts out of this paper then they could be separated into their own papers or paragraphs and still make sense at times. It just seemed to lack a sense of cohesiveness.