The task of assembling drawings and backgrounds together for each frame of an animated sequence has always been a tedious undertaking using conventional animation camera stands and has contributed to the high cost of ...
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This paper describes an animation package currently under development at the cornell program of computer graphics. The basic algorithm employed is linear or non-linear interpolation between successive pairs of key fra...
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ISBN:
(纸本)9781450373555
This paper describes an animation package currently under development at the cornell program of computer graphics. The basic algorithm employed is linear or non-linear interpolation between successive pairs of key frames. These key frames are composed of artwork input by the animator on a graphic tablet and displayed on either a black and white vector scope or a color halftone CRT. The initial working environment is two-dimensional, and the individual images are combined using a multiplane cel animation technique to produce depth and motion illusions. Real-time film previewing, utilizing an on-the-fly interpolation algorithm, provides the artist with instant playback of animated sequences.
Advances for achieving user control of a dynamic simulation of linked figures is presented. The formulation integrates forward and inverse kinematics specification within a mixed method of forward and inverse dynamics...
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This paper presents a novel framework for efficiently propagating the stroke-based user edits to the regions with similar colors and locations in high resolution images and videos. Our framework is based on the key ob...
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This paper presents a novel framework for efficiently propagating the stroke-based user edits to the regions with similar colors and locations in high resolution images and videos. Our framework is based on the key observation that the edit propagation intrinsically can also be achieved by utilizing recently proposed edge-preserving filters. Therefore, instead of adopting the traditional global optimization which may involve a time-consuming solution, our algorithm propagates edits with the aid of the edge-preserve filters. Such a propagation scheme has low computational complexity and supports multiple kinds of strokes for more flexible user interactions. Further, our method can be easily and efficiently implemented in GPU. The experimental results demonstrate the efficiency and user-friendliness of our approach.
Building energy simulation is valuable during the early stages of design, when decisions can have the greatest impact on energy performance. However, preparing digital design models for building energy simulation typi...
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Computing high-quality direct illumination in scenes with many lights is an open area of research. This paper presents a world-space caching mechanism called local illumination environments that enables interactive di...
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ISBN:
(纸本)1581135343
Computing high-quality direct illumination in scenes with many lights is an open area of research. This paper presents a world-space caching mechanism called local illumination environments that enables interactive direct illumination in complex scenes on a cluster of off-the-shelf PCs. A local illumination environment (LIE) caches geometric and radiometric information related to direct illumination. A LIE is associated with every octree cell constructed over the scene. Each LIE stores a set of visible lights, with associated occluders (if they exist). LIEs are effective at accelerating direct illumination because they both eliminate shadow rays for fully visible and fully occluded regions of the scene, and decrease the cost of shadow rays in other regions. Shadow ray computation for the partially occluded regions is accelerated using the cached potential occluders. One important implication of storing occluders is that rendering is accelerated while producing accurate hard and soft shadows. This paper also describes a simple perceptual metric based on Weber's law that further improves the effectiveness of LIEs in the fully visible and partially occluded regions. LIE construction is view-driven, continuously refined, and asynchronous with the shading process. In complex scenes of hundreds of thousands of polygons with up to a hundred lights, the LIEs improve rendering performance by 10x to 30x over a traditional ray tracer.
Placing shadows is difficult task since shadows depend on the relative positions of lights and objects in an unintuitive manner. To simplify the task of the modeler, we present a user interface for designing shadows i...
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ISBN:
(纸本)9781581135213
Placing shadows is difficult task since shadows depend on the relative positions of lights and objects in an unintuitive manner. To simplify the task of the modeler, we present a user interface for designing shadows in 3d environments. In our interface, shadows are treated as first-class modeling primitives just like objects and lights. To transform a shadow, the user can simply move, rescale or rotate the shadow as if it was a 2d object on the scene's surfaces. When the user transforms a shadow, the system moves lights or objects in the scene as required and updates the shadows in realtime during mouse movement. To facilitate interaction, the user can also specify constraints that the shadows must obey, such as never casting a shadow on the face of a character. These constraints are then verified in real-time, limiting mouse movement when necessary. We also integrate in our interface fake shadows typically used in computer animation. This allows the user to draw shadowed and non-shadowed regions directly on surfaces in the scene.
Our goal is to develop physically based lighting models and perceptually based rendering procedures for computergraphics that will allow synthetic images to be generated that are visually and measurably indistinct fr...
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Our goal is to develop physically based lighting models and perceptually based rendering procedures for computergraphics that will allow synthetic images to be generated that are visually and measurably indistinct from real-world images. The research implies the symbiotic relationship which could exist between computergraphics and digital imaging. This presentation describes how work at cornell's program of computergraphics is attempting to achieve this goal.
Accurate calculation of direct solar radiation with current methods is slow and frequently requires oversimplification of building geometry to obtain expedient performance simulations. This paper describes the use of ...
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Accurate calculation of direct solar radiation with current methods is slow and frequently requires oversimplification of building geometry to obtain expedient performance simulations. This paper describes the use of a fast new method for calculating direct solar gains on architectural CAD models at any stage in design. A pre-processing module computes direct incident solar radiation with high accuracy several orders of magnitude faster than common analytical approaches. The technique is illustrated using preliminary CAD models of two existing buildings that are gradually made more complex through the addition of intricate louvered shading devices, foliage, and adjacent urban structures. Each refinement allows EnergyPlus to calculate much more accurate direct solar gain data with only minimal increase in pre-processing time and no effect on energy simulation time.
This paper presents a new interactive rendering and display technique for complex scenes with expensive shading, such as global illumination. Our approach combines sparsely sampled shading (points) and analytically co...
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