We present a sketching interface for quickly and easily designing freeform models such as stuffed animals and other rotund objects. The user draws several 2D freeform strokes interactively on the screen and the system automatically constructs plausible 3D polygonal surfaces. Our system supports several modeling operations, including the operation to construct a 3D polygonal surface from a 2D silhouette drawn by the user: it inflates the region surrounded by the silhouette making wide areas fat, and narrow areas thin. Teddy, our prototype system, is implemented as a Java™ program, and the mesh construction is done in real-time on a standard PC. Our informal user study showed that a first-time user typically masters the operations within 10 minutes, and can construct interesting 3D models within minutes.

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Teddy: a sketching interface for 3D freeform design

As the number of 3D models available on the Web grows, there is an increasing need for a search engine to help people find them. Unfortunately, traditional text-based search techniques are not always effective for 3D data. In this article, we investigate new shape-based search methods. The key challenges are to develop query methods simple enough for novice users and matching algorithms robust enough to work for arbitrary polygonal models. We present a Web-based search engine system that supports queries based on 3D sketches, 2D sketches, 3D models, and/or text keywords. For the shape-based queries, we have developed a new matching algorithm that uses spherical harmonics to compute discriminating similarity measures without requiring repair of model degeneracies or alignment of orientations. It provides 46 to 245p better performance than related shape-matching methods during precision--recall experiments, and it is fast enough to return query results from a repository of 20,000 models in under a second. The net result is a growing interactive index of 3D models available on the Web (i.e., a Google for 3D models).

A search engine for 3D models

This paper explores a user interface technique which augments an immersive head tracked display with a hand-held miniature copy of the virtual environment We call this interface technique the Worlds in Miniature (WIM) metaphor By establishing a direct relationship between life-size objects in the virtual world and miniature objects in the WIM, we can use the WIM as a tool for manipulating objects in the virtual environment In addition to describing object manipulation, this paper explores ways in which Worlds in Miniature can act as a single unifying metaphor for such application independent interaction techniques as object selection, navigation, path planning, and visualization The WIM metaphor naturally offers multiple points of view and multiple scales at which the user can operate, all without requiring explicit modes or commands Informal user observation indicates that users adapt to the Worlds in Miniature metaphor quickly and that physical props are helpful in manipulating the WIM and other objects in the environment

Virtual reality on a WIM: interactive worlds in miniature

Understanding Virtual Reality arrives at a time when the technologies behind virtual reality have advanced to the point that it is possible to develop and deploy meaningful, productive virtual reality applications. The aim of this thorough, accessible exploration is to help you take advantage of this moment, equipping you with the understanding needed to identify and prepare for ways VR can be used in your field, whatever your field may be.


By approaching VR as a communications medium, the authors have created a resource that will remain relevant even as the underlying technologies evolve. You get a history of VR, along with a good look at systems currently in use. However, the focus remains squarely on the application of VR and the many issues that arise in the application design and implementation, including hardware requirements, system integration, interaction techniques, and usability. This book also counters both exaggerated claims for VR and the view that would reduce it to entertainment, citing dozens of real-world examples from many different fields and presenting (in a series of appendices) four in-depth application case studies.

* Substantive, illuminating coverage designed for technical and business readers and well-suited to the classroom.
* Examines VR's constituent technologies, drawn from visualization, representation, graphics, human-computer interaction, and other fields, and explains how they are being united in cohesive VR systems.
* Via a companion Web site, provides additional case studies, tutorials, instructional materials, and a link to an open-source VR programming system.

Table of Contents

Foreword 
Preface

Part I - What is Virtual Reality?
Chapter 1: Introduction to Virtual Reality - What it is and Where it Comes From
Chapter 2: VR the Medium

Part II - Virtual Reality Systems 
Chapter 3: Interface to the Virtual World -- Input 
Chapter 4: Interface to the Virtual World -- Output 
Chapter 5: Rendering a Virtual World 
Chapter 6: Interacting with a Virtual World 
Chapter 7: Virtual Reality Experience 
Chapter 8: Experience Design: Applying VR to a Problem
Chapter 9: What Dreams May Come: The Future of VR 

Appendices
A: NICE educational application (EVL) 
B: Crumbs visualization application (NCSA)
C: Aircraft wiring application (Boeing, Inc.) 
D: Placeholder artistic application (Interval Research)

Understanding Virtual Reality: Interface, Application, and Design

The Organization of Learning そして

Sketching communicates ideas rapidly through approximate visual images with low overhead (pencil and paper), no need for precision or specialized knowledge, and ease of low-level correction and revision. In contrast, most 3D computer modeling systems are good at generating arbitrary views of precise 3D models and support high-level editing and revision. The SKETCH application described in this paper attempts to combine the advantages of each in order to create an environment for rapidly conceptualizing and editing approximate 3D scenes. To achieve this, SKETCH uses simple non-photorealistic rendering and a purely gestural interface based on simplified line drawings of primitives that allows all operations to be specified within the 3D world.

SKETCH: an interface for sketching 3D scenes

The 3D components of today’s user interfaces are still underdeveloped. Direct interaction with 3D objects has been limited thus far to gestural picking, manipulation with linear transformations, and simple camera motion. Further, there are no toolkits for building 3D user interfaces. We present a system which allows experimentation with 3D widgets, encapsulated 3D geometry and behavior. Our widgets are first-class objects in the same 3D environment used to develop the application. This integration of widgets and application objects provides a higher bandwidth between interface and application than exists in more traditional UI toolkit-based interfaces. We hope to allow user-interface designers to build highly interactive 3D environments more easily than is possible with today’s tools.

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Three-dimensional widgets

We present two novel techniques for effectively selecting objects in immersive virtual environments using a single 6 DOF magnetic tracker. These techniques advance the state of the art in that they exploit the participant’s visual frame of reference and fully utilize the position and orientation data from the tracker to improve accuracy of the selection task. Preliminary results from pilot usability studies validate our designs. Finally, the two techniques combine to compensate for each other’s weaknesses.

Aperture based selection for immersive virtual environments

3D computer graphics is becoming more and more popular due to the increased availability of 3D hardware and software on all classes of computers. However, despite this growing popularity and the existence of a number of successful 3D graphics applications, particularly in CAD, CAE, and medical and scientific visualization, the field is still very immature, There are no widely accepted standards for hardware or software platforms; learning to implement or use 3D graphics software is still extremely laborious; and the most effective ways for humans to interact with synthetic 3D environments are still not clear.

The challenges of 3D interaction: a CHI '94 workshop

It is often difficult in computer graphics applications to understand spatial relationships between objects in a 3D scene or effect changes to those objects without specialized visualization and manipulation techniques. We present a set of three-dimensional tools (widgets) called “shadows” that not only provide valuable perceptual cues about the spatial relationships between objects, but also provide a direct manipulation interface to constrained transformation techniques. These shadow widgets provide two advances over previous techniques. First, they provide high correlation between their own geometric feedback and their effects on the objects they control. Second, unlike some other 3D widgets, they do not obscure the objects they control.

Kenneth P. Herndon

Papers

SKETCH: an interface for sketching 3D scenes

Three-dimensional widgets

Aperture based selection for immersive virtual environments

The challenges of 3D interaction: a CHI '94 workshop

Interactive shadows