Shadow maps are probably the most widely used means for the generation of shadows, despite their well known aliasing problems. In this paper we introduce perspective shadow maps, which are generated in normalized devi...
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ISBN:
(纸本)9781581135213
Shadow maps are probably the most widely used means for the generation of shadows, despite their well known aliasing problems. In this paper we introduce perspective shadow maps, which are generated in normalized device coordinate space, i.e., after perspective transformation. this results in important reduction of shadow map aliasing with almost no overhead. We correctly treat light source transformations and show how to include all objects which cast shadows in the transformed space. Perspective shadow maps can directly replace standard shadow maps for interactive hardware accelerated rendering as well as in high-quality, offline renderers.
the proceedings contains 84 papers presented at the conference, 55 of which are indexed separately. the papers are grouped under general headings that include the following: computer and information systems, engineeri...
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the proceedings contains 84 papers presented at the conference, 55 of which are indexed separately. the papers are grouped under general headings that include the following: computer and information systems, engineering economy, ergonomics, facilities planning and design, industrial and labor relations, management, manufacturing, mining, operations research, production and inventory control, quality control and reliability engineering, transportation and distribution, work measurement and methods engineering, and others.
Geometric transformations are most commonly represented as square matrices in computergraphics. Following simple geometric arguments we derive a natural and geometrically meaningful definition of scalar multiples and...
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ISBN:
(纸本)9781581135213
Geometric transformations are most commonly represented as square matrices in computergraphics. Following simple geometric arguments we derive a natural and geometrically meaningful definition of scalar multiples and a commutative addition of transformations based on the matrix representation, given that the matrices have no negative real eigenvalues. Together, these operations allow the linear combination of transformations. this provides the ability to create weighted combination of transformations, interpolate between transformations, and to construct or use arbitrary transformations in a structure similar to a basis of a vector space. these basic techniques are useful for synthesis and analysis of motions or animations. Animations through a set of key transformations are generated using standard techniques such as subdivision curves. For analysis and progressive compression a PCA can be applied to sequences of transformations. We describe an implementation of the techniques that enables an easy-to-use and transparent way of dealing with geometric transformations in graphics software. We compare and relate our approach to other techniques such as matrix decomposition and quaternion interpolation.
Good information design depends on clarifying the meaningful structure in an image. We describe a computational approach to stylizing and abstracting photographs that explicitly responds to this design goal. Our syste...
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ISBN:
(纸本)9781581135213
Good information design depends on clarifying the meaningful structure in an image. We describe a computational approach to stylizing and abstracting photographs that explicitly responds to this design goal. Our system transforms images into a line-drawing style using bold edges and large regions of constant color. To do this, it represents images as a hierarchical structure of parts and boundaries computed using state-of-the-art computer vision. Our system identifies the meaningful elements of this structure using a model of human perception and a record of a user's eye movements in looking at the photo;the system renders a new image using transformations that preserve and highlight these visual elements. Our method thus represents a new alternative for non-photorealistic rendering both in its visual style, in its approach to visual form, and in its techniques for interaction.
We present a new method for real-time rendering of objects with complex isotropic BRDFs under distant natural illumination, as specified by an environment map. Our approach is based on spherical frequency space analys...
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ISBN:
(纸本)9781581135213
We present a new method for real-time rendering of objects with complex isotropic BRDFs under distant natural illumination, as specified by an environment map. Our approach is based on spherical frequency space analysis and includes three main contributions. Firstly, we are able to theoretically analyze required sampling rates and resolutions, which have traditionally been determined in an ad-hoc manner. We also introduce a new compact representation, which we call a spherical harmonic reflection map (SHRM), for efficient representation and rendering. Finally, we show how to rapidly prefilter the environment map to compute the SHRM-our frequency domain prefiltering algorithm is generally orders of magnitude faster than previous angular (spatial) domain approaches.
this paper presents an example-based method for calculating skeleton-driven body deformations. Our example data consists of range scans of a human body in a variety of poses. Using markers captured during range scanni...
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ISBN:
(纸本)9781581135213
this paper presents an example-based method for calculating skeleton-driven body deformations. Our example data consists of range scans of a human body in a variety of poses. Using markers captured during range scanning, we construct a kinematic skeleton and identify the pose of each scan. We then construct a mutually consistent parameterization of all the scans using a posable subdivision surface template. the detail deformations are represented as displacements from this surface, and holes are filled smoothly within the displacement maps. Finally, we combine the range scans using k-nearest neighbor interpolation in pose space. We demonstrate results for a human upper body with controllable pose, kinematics, and underlying surface shape.
this paper describes a new method for contouring a signed grid whose edges are tagged by Hermite data (i.e;exact intersection points and normals). this method avoids the need to explicitly identify and process "f...
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ISBN:
(纸本)9781581135213
this paper describes a new method for contouring a signed grid whose edges are tagged by Hermite data (i.e;exact intersection points and normals). this method avoids the need to explicitly identify and process "features" as required in previous Hermite contouring methods. Using a new, numerically stable representation for quadratic error functions, we develop an octree-based method for simplifying contours produced by this method. We next extend our contouring method to these simpli£ed octrees. this new method imposes no constraints on the octree (such as being a restricted octree) and requires no "crack patching". We conclude with a simple test for preserving the topology of the contour during simpli£cation.
In this paper we present a novel method for creating realistic, controllable motion. Given a corpus of motion capture data, we automatically construct a directed graph called a motion graph that encapsulates connectio...
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ISBN:
(纸本)9781581135213
In this paper we present a novel method for creating realistic, controllable motion. Given a corpus of motion capture data, we automatically construct a directed graph called a motion graph that encapsulates connections among the database. the motion graph consists both of pieces of original motion and automatically generated transitions. Motion can be generated simply by building walks on the graph. We present a general framework for extracting particular graph walks that meet a user's specifications. We then show how this framework can be applied to the specific problem of generating different styles of locomotion along arbitrary paths.
We present a method for designing truss structures, a common and complex category of buildings, using non-linear optimization. Truss structures are ubiquitous in the industrialized world, appearing as bridges, towers,...
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ISBN:
(纸本)9781581135213
We present a method for designing truss structures, a common and complex category of buildings, using non-linear optimization. Truss structures are ubiquitous in the industrialized world, appearing as bridges, towers, roof supports and building exoskeletons, yet are complex enough that modeling them by hand is time consuming and tedious. We represent trusses as a set of rigid bars connected by pin joints, which may change location during optimization. By including the location of the joints as well as the strength of individual beams in our design variables, we can simultaneously optimize the geometry and the mass of structures. We present the details of our technique together with examples illustrating its use, including comparisons with real structures.
Cutting and pasting to combine different elements into a common structure are widely used operations that have been successfully adapted to many media types. Surface design could also benefit from the availability of ...
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ISBN:
(纸本)9781581135213
Cutting and pasting to combine different elements into a common structure are widely used operations that have been successfully adapted to many media types. Surface design could also benefit from the availability of a general, robust, and efficient cut-and-paste tool, especially during the initial stages of design when a large space of alternatives needs to be explored. Techniques to support cut-and-paste operations for surfaces have been proposed in the past, but have been of limited usefulness due to constraints on the type of shapes supported and the lack of real-time interaction. In this paper, we describe a set of algorithms based on multiresolution subdivision surfaces that perform at interactive rates and enable intuitive cut-and-paste operations.
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