Dennis Cosgrove

Alice: lessons learned from building a 3D system for novices

We present lessons learned from developing Alice, a 3D graphics programming environment designed for undergraduates with no 3D graphics or programming experience. Alice is a Windows 95/NT tool for describing the time-based and interactive behavior of 3D objects, not a CAD tool for creating object geometry. Our observations and conclusions come from formal and informal observations of hundreds of users. Primary results include the use of LOGO-style egocentric coordinate systems, the use of arbitrary objects as lightweight coordinate systems, the launching of implicit threads of execution, extensive function overloading for a small set of commands, the careful choice of command names, and the ubiquitous use of animation and undo.

Using a large projection screen as an alternative to head-mounted displays for virtual environments

Head-mounted displays for virtual environments facilitate an immersive experience that seems more real than an experience provided by a desk-top monitor [18]; however, the cost of head-mounted displays can prohibit their use. An empirical study was conducted investigating differences in spatial knowledge learned for a virtual environment presented in three viewing conditions: head-mounted display, large projection screen, and desk-top monitor. Participants in each condition were asked to reproduce their cognitive map of a virtual environment, which had been developed during individual exploration of the environment along a predetermined course. Error scores were calculated, indicating the degree to which each participants map differed from the actual layout of the virtual environment. No statistically significant difference was found between the head-mounted display and large projection screen conditions. An implication of this result is that a large projection screen may be an effective, inexpensive substitute for a head-mounted display.

Adaptive unwrapping for interactive texture painting

We present a method for dynamically generating an efficient texture bitmap and its associated UV-mapping in an interactive texture painting system for 3D models. Typical 3D texture painting programs require the user to explicitly define the underlying UV-mapping from 3D geometry to 2D bitmap prior to painting. This mapping is unchanged by the painting process. However, a predefined UV-mapping can cause distortion at arbitrary locations and waste bitmap memory in unpainted areas. To solve these problems, we propose an adaptive unwrapping mechanism where the system dynamically creates a tailored UV-mapping for newly painted polygons during the interactive painting process. This eliminates the distortion of brush strokes, and the resulting texture bitmap is more compact because the system allocates texture space only for the painted polygons. In addition, this dynamic texture allocation allows the user to paint smoothly at any zoom level. This technique can be efficiently implemented using standard 3D rendering engines, and the painted models can be stored as standard textured polygonal models. We implemented a prototype system, called Chameleon, and our users’ experiences suggest that our technique is very useful for simple painting by casual users.

Mediated transfer: Alice 3 to Java

In this paper, we describe a pedagogy for an undergraduate programming course using Alice 3 and Java. We applied the educational theory of mediated transfer to develop a new version of the Alice system and accompanying instructional materials. The pedagogy was implemented and tested over two years. Student test scores in experimental, treatment course sections showed dramatic improvement over scores in comparable non-treatment sections.

Automatically generating tutorials to enable middle school children to learn programming independently

Enabling middle school children to learn from code shared on the internet may provide computer science learning opportunities to those who would not otherwise have them. We augmented a programming environment designed for middle school children to automatically generate tutorials from code snippets in order to help users learn new programming skills. In our new system, users select code snippets from a program shared on the web and then complete an automatically generated tutorial in order to re-create that snippet within their own program. To evaluate the potential learning gains from our generated tutorials, we conducted a between-subjects study in which we evaluated the performance of children introduced to new programming constructs through automatically generated tutorials. Participants who used the automatically generated tutorials performed 64% better on a near transfer task compared to participants without generated tutorials.

Alice: easy to use interactive 3D graphics

Alice is a rapid prototyping system used to create three dimensional graphics simulations like those seen in virtual reality applications. Alice uses an interpreted language called Python as its scripting language to implement user actions. This interactive development environment allows users to explore many more design options than is possible in a compiled language environment. The alpha version of Alice for Windows 95 is available for free over the intemet, with the beta release scheduled for August.

Alice: easy to learn interactive 3D graphics

Alice is a rapid prototyping system used to create three dimensional graphics simulations like those seen in virtual reality applications. Alice uses an interpreted language called Python as its scripting language to implement user actions. This interactive development environment allows users to explore many more design options than is possible in a compiled language environment. The beta version of Alice for Windows 95 and NT 4.0 is available for free over the Internet from http://alice.cs.cmu.edu.

Special session in honor of randy pausch

Randy Pausch is an inspiration to all with his research, teaching, the way he has lived his life, and his courage while confronting pancreatic cancer. This session brings together people he has touched through various phases of his career to discuss his research and legacy.

Tutorial: Concurrency with Alice 3 and Java

In this special session, attendees will learn about techniques for teaching concepts of concurrency with Alice 3s latest release of a Java IDE plugin. The new plugin makes use of Java 8s lambda expression to provide a Do together control structure with simpler syntax. Using this technique and Java 8 plugin, students in early-level programming courses can make use of Alices Do together control structure to create concurrent threads in their Java code.

Tutorial: team projects with Alice 3

In this special session, attendees learn about techniques of teaching with team projects with Alice 3s new Save Type, Import Type, and Merge capabilities. Using this technique, students in introductory level programming courses can participate in team projects where students work as a team in various stages of design, development, and testing. As part of this process students may work independently to code one or more classes and then merge their work with that of other members of the team to create the final project.