John F. Hughes's research while affiliated with Brown University and other places

Publications (77)

Chapter
Modeling 3D shapes from a single-view user sketch leverages on user’s ability to draw contours of shapes well and allows the user to draw what he is thinking of directly. While the problem of making the inference from an arbitrary complex sketch remains challenging, algorithms have been proposed to solve it for a number of restricted cases. Earlier...
Article
Full-text available
We introduce a new method for coloring 3D line fields and show results from its application in visualizing orientation in DTI brain data sets. The method uses Boy's surface, an immersion of RP2 in 3D. This coloring method is smooth and one-to-one except on a set of measure zero, the double curve of Boy's surface.
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Full-text available
We present a smooth, everywhere C k , analytic surface representation for closed surfaces of arbitrary topology. We demonstrate fitting this representation to meshes of varying resolutions and sampling quality. The fitting process is adaptive and provides controls for both the average and the maximum allowable error. The representation is suitable...
Conference Paper
Touchpad and touchscreen interaction using multiple fingers is emerging as a valuable form of high-degree-of-freedom input. While bimanual interaction has been extensively stud- ied, touchpad interaction using multiple fingers of the same hand is not yet well understood. We describe two experi- ments on user perception and control of multi-touch in...
Article
We describe a GPU-based algorithm for rendering a D model as a line drawing, based on the insight that a line drawing can be understood as an abstraction of a shaded image. We thus render lines along tone boundaries or thin dark areas in the shaded image. We extend this notion to the dual: we render highlight lines along thin bright areas and tone...
Article
This paper introduces a framework to design optical splitting tree to perform computational photography tasks that require many sensors with a common optical axis. As the number of sensors increases, designing a good optical system is often difficult because the components have nonideal characteristics. The authors describe an optimization tool tak...
Article
This interactive system for garment creation determines a garment's shape and how the character wears it based on a user-drawn sketch. The system then uses distances between the 2D garment silhouette and the character model to infer remaining distance variations in 3D.
Conference Paper
We introduce SmoothSketh---a system for inferring plausible 3D free-from shapes from visible-contour sketches. In our system, a user's sketch need not be a simple closed curve as in Igarashi's Teddy [1999], but may have cusps and T-junctions, i.e., endpoints of hidden parts of the contour. We follow a process suggested by Williams [1994] for inferr...
Article
We introduce SmoothSketh---a system for inferring plausible 3D free-from shapes from visible-contour sketches. In our system, a user's sketch need not be a simple closed curve as in Igarashi's Teddy [1999], but may have cusps and T-junctions, i.e., endpoints of hidden parts of the contour. We follow a process suggested by Williams [1994] for inferr...
Article
Dreams in High Fidelity is a painting that evolves. It was designed and rendered with the Electric Sheep screen-saver, a cyborg mind composed of 30,000 computers and people mediated by a genetic algorithm. Physically it consists of a small computer ...
Conference Paper
The mouse cursor acts as a digital proxy for a finger on graphical displays. Our hands, however, have ten fingers and many degrees of freedom that we use to interact with the world. We posit that by creating graphical cursors that reflect more of the hand's physical properties, we can allow for richer and more fluid interaction. We demonstrate this...
Article
Full-text available
Video matting is the process of pulling a high-quality alpha matte and foreground from a video sequence. Current techniques require either a known background (e.g., a blue screen) or extensive user interaction (e.g., to specify known foreground and background elements). The matting problem is generally under-constrained, since not enough informatio...
Article
We present an interactive system that lets a user move and deform a two-dimensional shape without manually establishing a skeleton or freeform deformation (FFD) domain beforehand. The shape is represented by a triangle mesh and the user moves several vertices of the mesh as constrained handles. The system then computes the positions of the remainin...
Article
Hako-ne is an augmented reality hybrid art/technology project. Users will be able to see characters of 3D musical notes moving on each side of the augmented musical dollhouse by using a handheld Optical See-Through Information Viewer (OSTV), which consists ...
Conference Paper
This paper introduces spatial keyframing, a technique for performance-driven character animation. In traditional temporal keyframing, key poses are defined at specific points in time: i.e., we define a map from a set key times to the configuration space of the character and then extend this map to the entire timeline by interpolation. By contrast,...
Article
Current methods of digitizing handwritten music for typesetting re-main far from ideal despite many years for music typesetting pro-grams to mature. There are essentially two categories of programs in this area. The first of these categories contains programs such as Sibelius [Sibelius 2005] which make no distinction between note pitch and note dur...
Article
Full-text available
Algorithms that detect silhouettes, creases, and other edge based features often perform per-edge and per-face mesh computations using global adjacency information. These are unsuitable for hardware-pipeline implementation, where programmability is at the vertex and pixel level and only local information is available. Card and Mitchell and Gooch ha...
Conference Paper
We present a technique for scrolling through documents that is simple to implement and requires no special hardware. This is accomplished by simulating a hardware scroll ring--a device that maps circular finger motion into vertical scrolling. The technique performs at least as well as a mouse wheel for medium and long distances, and is preferred by...
Article
Single view sketch-based modelers like SKETCH and Teddy can be powerful tools, but sometimes their inferences are inadequate: in Teddy, for example, if one draws an animal shape, the centerline of the tail will always lie in a plane rather than being curved in 3D. In these cases, multiple-view sketching seems like a reasonable solution: a single sk...
Article
We present a method for simply and interactively creating basic garments for dressing virtual characters in applications like video games. The user draws an outline of the front or back of the garment, and the system makes reasonable geometric inferences about the overall shape of the garment (ignoring constraints arising from physics and from the...
Article
Sketching rough diagrams is a useful tool for communica- tion and planning. However, static diagrams are often insuf- ficient for expressing motion. While for many applications animation provides an effective depiction of movement and temporal relationships, it is difficult and often tedious to cre- ate. We explore the use of motion recording techn...
Article
Introduction Putting clothes on a 3D character is often a tedious, timeconsuming task. A typical approach is to place parts of the clothes around the target body as rigid thin plates and use a simulation to enforce "stitch-together" constraints and show the effects of gravity [Volino and Magnenat-Thalmann 2000]. The 3D character may be placed in a...
Conference Paper
This paper describes a framework for introducing visually smooth surfaces into sketch-based freeform modeling systems. An existing sketch-based freeform modeling system generates rough polygonal meshes with uneven triangulations after each operation. Our approach generates a dense, visually smooth polygonal mesh by beautifying and refining the orig...
Conference Paper
Full-text available
We define a parameterization for an n-holed tori based on the hyperbolic polygon. We model the domain using a manifold with 2n+ 2 charts, and linear fractional transformations for transition functions. We embed the manifold using standard spline techniques to produce a surface.
Article
this paper, we discuss our preliminary efforts at using variational implicit surfaces [Turk, 2000] as a representation in a free-form modeler. We also discuss the implementation of several operations within this context, and a collection of user-interaction elements that work well together to make modeling interesting hierarchies simple. These incl...
Conference Paper
We present a system that lets a designer directly annotate a D model with strokes, imparting a personal aesthetic to the non-photorealistic rendering of the object. The artist chooses a "brush" style, then draws strokes over the model from one or more viewpoints. When the system renders the scene from any new viewpoint, it adapts the number and pla...
Article
With the advent of sketch-based methods for shape construction, theres a new degree of power available in the rapid creation of approximate shapes. Sketch [Zeleznik, 1996] showed how a gesture-based modeler could be used to simplify conventional CSG-like shape creation. Teddy [Igarashi, 1999] extended this to more free-form models, get-ting much of...
Article
With the advent of sketch-based methods for shape construction, there's a new degree of power available in the rapid creation of approximate shapes. Sketch [Zeleznik, 1996] showed how a gesture-based modeler could be used to simplify conventional CSG-like shape creation. Teddy [Igarashi, 1999] extended this to more free-form models, getting much of...
Article
This paper introduces a new type of interface for 3D drawings that improves the usability of gestural interfaces and augments typical command-based modeling systems. In our suggestive interface, the user gives hints about a desired operation to the system by highlighting related geometric components in the scene. The system then infers possible ope...
Article
We describe the use of non-verbal features in voice for direct control of interactive applications. Traditional speech recognition interfaces are based on an indirect, conversational model. First the user gives a direction and then the system performs certain operation. Our goal is to achieve more direct, immediate interaction like using a button o...
Conference Paper
Full-text available
Images are programs. They are usually simple instructions to a very specialized interpreter that renders them on screen. Image formats therefore correspond to different programming languages, each with distinctive properties of program size and accuracy. Image-processing languages render large images from small pieces of code. We present Evolver, a...
Article
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 revi...
Conference Paper
Full-text available
We apply simple techniques from traditional artistic composition to the art-based rendering of interactive 3D scenes. A human scene-modeler makes choices about composition in a scene and our sys-tem dynamically adjusts the rendering attributes of objects in the scene to achieve the desired effects for a given view. We can selec-tively group scene e...
Conference Paper
We describe the use of non-verbal features in voice for direct control of interactive applications. Traditional speech recognition interfaces are based on an indirect, conversational model. First the user gives a direction and then the system performs certain operation. Our goal is to achieve more direct, immediate interaction like using a button o...
Article
The problem of interactively creating 3D scenes from 2D input is a compelling one, and recent progress has been exciting. We present our system, Harold, which combines ideas from existing techniques and introduces new concepts to make an interactive system for creating 3D worlds. The interface paradigm in Harold is drawing:all objects are created s...
Article
In previous work [6], we presented an algorithm for rendering virtual scenes using art-based styles. We demonstrated the ability to render fur, grass, and trees in a stylized manner that evoked the complexity of these textures without representing all their components explicitly. We achieved this with stroke-based procedural textures that generated...
Article
We show how to easily create a right-handed orthonormal basis, given a unit vector, in 2−, 3−, and 4-space.
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Heuristics that exploit bouning boxes are common in algorithms for rendering, modeling, and animation. While experience has shown that bounding boxes improve the performance of these algorithms in practice, the previous theoretical analysis has concluded that bounding boxes perform poorly in the worst case. This paper reconciles this discrepancy by...
Article
We present a new particle-based surface representation with which a user can interactively sculpt free-form surfaces. The particles maintain mesh connectivity and operate under rules that lead them to form triangulations with properties that make them suitable for use in subdivision. A user interactively guides the particles, which we call skin, to...
Article
Full-text available
We describe an extension of B-splines to surfaces of arbitrary topology, including arbitrary boundaries. The technique inherits many of the properties of B-splines: local control, a compact representation, and guaranteed continuity of arbitrary degree. The surface is specified using a polyhedral control mesh instead of a rectangular one; the result...
Article
We describe an efficient (no square roots or trigonometric functions) method to const ruct the 3 × 3 matrix that rotates a unit vector f into another unit vector t, rotating about the axis f × t. We give experiment al results showing this method is faster than previously known methods. An implementation in C is provided.
Conference Paper
closely matches the one she is used to - namely pencil and paper. The ability to specify nonplanar 3D curves is of fundamen- tal importance in 3D modeling and animation systems. Ef- fective techniques for specifying such curves using 2D in- put devices are desirable, but existing methods typically re- quire the user to edit the curve from several v...
Article
kin. Physcially-based modeling: Past, present future. In SIGGRAPH Panel Proceedings, pages 203--205, 1989. Part of panel chaired by Demetri Terzopoulis and John Platt. [WK88] Andrew Witkin and Michael Kass. Spacetime constraints. Computer Graphics, 22:159--168, 1988. Proceedings SIGGRAPH '88. [WKTF88] Andrew Witkin, Michael Kass, Demetri Terzopoulo...
Article
This paper presents the architecture for an extensible toolkit used in construction and rapid prototyping of three dimensional interfaces, interactive illustrations, and three dimensional widgets. The toolkit provides methods for the direct manipulation of 3D primitives which can be linked together through a visual programming language to create co...
Article
Full-text available
We present an interactive modeling and animation system that facilitates the integration of a variety of simulation and animation paradigms. This system permits the modeling of diverse objects that change in shape, appearance, and behavior over time. Our system thus extends modeling tools to include animation controls. Changes can be effected by va...
Conference Paper
Full-text available
Let S be a family of n polyhedral objects in d dimen- sions, with aspect ratio bound CY and scale factor bound (T. Let K,(S) denote the number of object-pairs in S with nonempty intersection, and let &(S) denote the number of pairs whose enclosing balls intersect. We in- vestigate the worst-case behavior of the following ratio:
Article
C151--C158, September 1997. [WFB87] Andrew Witkin, Kurt Fleischer, and Alan H. Barr. Energy constraints on parameterized models. SIGGRAPH '87 Conference Proceedings, 21(4):225--232, (Anaheim, CA, July, 1987). [WG97] Jane Wilhelms and Allen Van Gelder. Anatomically based modeling. In Computer Graphics, pages 173--180, Los Angeles, Ca., August 1997....
Article
Accuracy is the ubiquitous goal of dynamic simulation, in order to yield the "correct" motion. But for creating animation, what is really of interest is "plausible" motion, which is somewhat different. We discuss what we mean by plausible simulation, how it differs from "accurate" simulation, and whywe think it's a worthwhile area to study. The dis...
Article
We describe a new approach for simulating apparent camera motion through a 3D environment. The approach is motivated by a traditional technique used in 2D cel animation, in which a single background image, which we call a multiperspective panorama,is used to incorporate multiple views of a 3D environment as seen from along a given camera path. When...
Article
We present an interactive system for creating pen-and-ink-style line drawings from greyscale images in which the strokes of the rendered illustration follow the features of the original image. The user, via new interaction techniques for editing a direction field, specifies an orientation for each region of the image; the computer draws oriented st...
Article
In this paper we present methods to smoothly interpolate orientations, given N rotational keyframes of an object along a trajectory. The methods allow the user to impose constraints on the rotational path, such as the angular velocity at the endpoints of the trajectory. We convert the rotations to quaternions, and then spline in that non-Euclidean...
Article
Full-text available
We present a method for approximating an isosurface with a smooth parametric representation. From the isosurface we first produce a patch mesh, a description of how many surface patches there are and how they are connected. We then create a smooth surface from the patch mesh. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Obje...
Conference Paper
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 revi...
Article
Surface-based rendering techniques, particularly those that extract a polygonal approximation to an isosurface, are widely used in volume visualization. As dataset size increases though, the computational demands of these methods can overwhelm typically available computing resources. Recent work on accelerating such techniques has focused on prepro...
Article
Annotation is a key activity of data analysis. However, current data analysis systems focus almost exclusively on visualization. We propose a system which integrates annotations into a visualization system. Annotations are embedded in 3D data space, using the Post-it 1 metaphor. This embedding allows contextualbased information storage and retrieva...
Article
This paper presents the architecture for an extensible toolkit used in construction and rapid prototyping of three dimensional interfaces, interactive illustrations, and three dimensional widgets. The toolkit provides methods for the direct manipulation of 3D primitives which can be linked together through a visual programming language to create co...
Article
Introduction Today's user interfaces for most 3D graphics applications still depend heavily on 2D GUIs and keyboard input. There have been several recent attempts both to extend these user interfaces into 3D and to describe intermediary 3D widgets 1 that control application objects [3; 4; 5; 7; 13; 15]. Even though this style of interaction is a st...
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Full-text available
Free-form deformation (FFD) is a powerful modeling tool, but controlling the shape of an object under complex deformations is often difficult. The interface to FFD in most conventional systems simply represents the underlying mathematics directly; users describe deformations by manipulating control points. The difficulty in controlling shape precis...
Conference Paper
We describe two instances in which precise mechanical calibration of virtual environments equipment has been replaced by automated algorithmic calibration through software that encapsulates the hardware design and uses a goal-based approach to adjust calibration parameters. We describe a back-projection system for adjusting the assumed locations of...
Conference Paper
We describe an easily implemented and computationally feasible method for smoothly transitioning from one sampled volumetric model to another. This induces a transition between isosurfaces of the two models. The technique is based on interpolating smoothly between the Fourier transforms of the two volumetric models and then transforming the results...
Conference Paper
In this paper we present methods to smoothly interpolate orientations, given N rotational key frames of an object along a trajectory. The methods allow the user to impose constraints on the rotational path, such as the angular velocity at the endpoints of the trajectory. We convert the rotations to quaternions, and then spline in that non-Euclidea...
Article
We present a new interactive modeling technique based on the notion of sculpting a solid material. A sculpting tool is controlled by a 3D input device and the material is represented by voxel data; the tool acts by modifying the values in the voxel array, much as a "paint" program's "paintbrush" modifies bitmap values. The voxel data is converted t...
Conference Paper
Full-text available
We present a new interactive modeling technique based on the notion of sculpting a solid material. A sculpting tool is controlled by a D input device and the material is represented by voxel data; the tool acts by modifying the values in the voxel array, much as a "paint" program's "paintbrush" modifies bitmap values. The voxel data is converted to...
Article
Nonphotorealistic rendering (NPR) can help make comprehensible but simple pictures of complicated objects by employing an economy of line. But current nonphotorealistic rendering is primarily a batch process. This paper presents a real-time nonphotorealistic renderer that deliberately trades accuracy and detail for speed. Our renderer uses a method...
Article
Full-text available
We present an interactive modeling and animation system that enables the close integration of a variety of simulation and animation paradigms. The system models diverse objects undergoing a wide variety of changes over time. These changes can be specified by different methods of control. Real-time update speeds are facilitated through maintenance o...
Article
In this paper we explore the possibilities of creating live presentations that can be adapted on the fly in response to the audience and time constraints. Our work also allows presenters to manage multiple versions of a presentation, each customized to a given situation. Customizable pre- sentations are structured by nested sub-paths; this organi -...
Article
Full-text available
We present a set of algorithms for rendering shadows using the stencil buffer and shadow volume geometry. It can achieve greater performance than previous methods by applying a series of techniques for culling, clipping, and simplifying shadow volume geometry. The performance of many 3D games is currently limited by pixel fill rate, and the clippin...

Citations

... This method can generate only simple cloth meshes which needed to be processed further to complete a detailed cloth. An interactive way for putting and manipulating clothes on a 3D model was introduced by Igarashi & Hughes (2002) [26]. 2D patterns are used to generate 3D cloth in this method and this can be used to model simple style cloth without folding and also because of the computational cost cloth-cloth collision is disregarded while calculating surface constraints of 3D cloth mesh. ...
... Finite element meshes other is smooth enough. Mesh refinement plus geometric fairing algorithm is proposed in Igarashi and Hughes (2003). These techniques could be used to fillet a sharp edge on a mechanical model and the modification could be constrained in a local zone (a + ). ...
... The special orthogonal group SO(n) plays an important role in mechanics, computer graphics, and other applications, due in large part to its connection with rigid body rotations when n = 3. The task of interpolating SO(3)-valued functions, in particular, arises in robotics [43], animation [2, 12, 34], and the discretization of Cosserat continuum theories [6, 35]. This paper studies schemes for interpolating such functions, with an emphasis on the case n = 3 but with an eye toward general n as well. ...
... However, a very interesting recent development in the field of computer graphics has been real-time sculpting in virtual reality-first proposed by Galyean & Hughes (1991). This draws heavily on the rapidly expanding field of three-dimensional volume graphics, which is itself driven particularly by medical imaging and by animation. ...
... An alternative approach to aid users in creating 3D space curves is to assume the curves represent underlying man-made structure. The SKETCH interface [Zeleznik et al. 1996] starts by allowing the user to sketch box like forms which anchor additional 3D space curve sketching operations. Schmidt et al. [2009b] uses sketching on an initial ground plane to build a scaffold which acts as a set of visual constraints for sketching additional 3D curves. ...
... Beyond using voice interaction to converse with other players [231], recent advances in software and hardware technology [7] have made it possible to use voice interaction to control avatar actions and in-game events [8]. Two popular approaches exist here: "voice-as-sound" [88,99] and "voice-as-speech" [8,37]. Voice-as-sound uses players' voice characteristics such as pitch and tone [88,99]. ...
Citing conference paper
... Related algorithms for reconstructing shape from a network of contours have been developed in computer vision, e.g., [Roberts 1963], and sketch-based modeling, e.g., [Karpenko and Hughes 2006]. Our case is distinct in that we begin with a 3D input surface rather than 2D measurements. ...
Citing conference paper
... e research on computer graphics has always been one of the hot fields in the domain of computer science, and its major content includes the representation method of graphics in the computer, the calculation of graphics, and the principle and algorithm of display. In 1962, E. Sutherland from MIT Lincoln Laboratory used the term "Computer Graphics" for the first time in his paper, proving that interactive Computer Graphics is a feasible and useful research field [1,2]. us, Computer Graphics as a new branch of independent science was confirmed. ...
... For the latter, the area is calculated on which the color objects are distributed in the plane. Palus and Bereska conclude that when comparing the cluster sizes for the examined conversion, the [23] color space delivers the best results in terms of object recognition. ...
... We find the rotation between the oriented surface normal of the contact plane and the gravity vector (which is the negative surface normal of the table plane) using Rodrigues' formula [11]. While we describe our method in the context We highlight in red an input point and the associated predicted contact point probability. ...