Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945349
G. Pasko, A. Pasko, T. Ikedo, C. Vilbrandt
Issues concerning the digital preservation of the shapes and internal structures of culturally valuable objects are discussed. An overview of existing approaches to digital shape preservation and corresponding problems is given. Our approach is based on using constructive modeling, which reflects the logical structure of the shapes. We examine and select those mathematical representations of shapes that fit the purposes of long-term digital preservation. Constructive solid geometry (CSG) is applied to the modeling of a Japanese temple (the Sazaedo) with a unique internal structure. The traditional Japanese lacquer ware called 'Shikki' is modeled using a function representation (F-Rep). We describe the Virtual Shikki project, which is aimed at presenting the virtual shapes and textures of lacquer-ware on the World Wide Web.
{"title":"Virtual Shikki and Sazaedo: shape modeling in digital preservation of Japanese lacquer ware and temples","authors":"G. Pasko, A. Pasko, T. Ikedo, C. Vilbrandt","doi":"10.1109/SCCG.2001.945349","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945349","url":null,"abstract":"Issues concerning the digital preservation of the shapes and internal structures of culturally valuable objects are discussed. An overview of existing approaches to digital shape preservation and corresponding problems is given. Our approach is based on using constructive modeling, which reflects the logical structure of the shapes. We examine and select those mathematical representations of shapes that fit the purposes of long-term digital preservation. Constructive solid geometry (CSG) is applied to the modeling of a Japanese temple (the Sazaedo) with a unique internal structure. The traditional Japanese lacquer ware called 'Shikki' is modeled using a function representation (F-Rep). We describe the Virtual Shikki project, which is aimed at presenting the virtual shapes and textures of lacquer-ware on the World Wide Web.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126852145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945337
R. Krasauskas
We present an informal introduction to the theory of toric surfaces from the viewpoint of geometric modeling. Bezier surfaces and many well-known low-degree rational surfaces are found to be toric. Bezier-like control point schemes for toric surfaces are defined via mixed trigonometric-polynomial parametrizations. Many examples are considered: quadrics, cubic Mobius strip, quartic 'pillow', 'crosscap' and Dupin cyclides. A 'pear' shape modeling is presented.
{"title":"Shape of toric surfaces","authors":"R. Krasauskas","doi":"10.1109/SCCG.2001.945337","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945337","url":null,"abstract":"We present an informal introduction to the theory of toric surfaces from the viewpoint of geometric modeling. Bezier surfaces and many well-known low-degree rational surfaces are found to be toric. Bezier-like control point schemes for toric surfaces are defined via mixed trigonometric-polynomial parametrizations. Many examples are considered: quadrics, cubic Mobius strip, quartic 'pillow', 'crosscap' and Dupin cyclides. A 'pear' shape modeling is presented.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125873700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945360
A. Vilanova, E. Gröller, R. Wegenkittl, A. König
Virtual endoscopy is a promising medical application for volume rendering techniques where perspective projection is mandatory. Most of the acceleration techniques for direct volume rendering make use of parallel projection. This is also the case of the current generation of VolumePro systems, which achieve real-time frame rates but unfortunately just provide parallel projection. In this paper, an algorithm to approximate perspective volume rendering using parallel projected slabs is presented. The introduced error due to the approximation is investigated. Based on the error estimation, an improvement to the basic algorithm is presented. The improvement increases the frame rate keeping the global maximal error bounded. The usability of the algorithm is shown through the virtual endoscopic investigation of various types of medical data sets.
{"title":"Perspective projection through parallel projected slabs for virtual endoscopy","authors":"A. Vilanova, E. Gröller, R. Wegenkittl, A. König","doi":"10.1109/SCCG.2001.945360","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945360","url":null,"abstract":"Virtual endoscopy is a promising medical application for volume rendering techniques where perspective projection is mandatory. Most of the acceleration techniques for direct volume rendering make use of parallel projection. This is also the case of the current generation of VolumePro systems, which achieve real-time frame rates but unfortunately just provide parallel projection. In this paper, an algorithm to approximate perspective volume rendering using parallel projected slabs is presented. The introduced error due to the approximation is investigated. Based on the error estimation, an improvement to the basic algorithm is presented. The improvement increases the frame rate keeping the global maximal error bounded. The usability of the algorithm is shown through the virtual endoscopic investigation of various types of medical data sets.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115432491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945353
A. Abbas, László Szirmay-Kalos, G. Szijártó, Tamás Horváth, Tibor Fóris
Rendering systems often represent curved surfaces as a mesh of planar polygons that are shaded to add realism and to restore a smooth appearance. To increase the rendering speed, complex operations, such as the evaluation of the local illumination model or texture transformation, are executed for just a few knot points, and the values at other points are interpolated. Usually, a linear transformation is used, since it can be easily implemented in hardware. However, the colour distribution and texture transformation may be strongly nonlinear, so a linear interpolation may introduce severe artifacts. Thus, this paper proposes two-variate quadratic interpolation to tackle this problem and demonstrates that it can be implemented in hardware. A software simulation and a VHDL description of the shading hardware are also presented.
{"title":"Quadratic interpolation in hardware Phong shading and texture mapping","authors":"A. Abbas, László Szirmay-Kalos, G. Szijártó, Tamás Horváth, Tibor Fóris","doi":"10.1109/SCCG.2001.945353","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945353","url":null,"abstract":"Rendering systems often represent curved surfaces as a mesh of planar polygons that are shaded to add realism and to restore a smooth appearance. To increase the rendering speed, complex operations, such as the evaluation of the local illumination model or texture transformation, are executed for just a few knot points, and the values at other points are interpolated. Usually, a linear transformation is used, since it can be easily implemented in hardware. However, the colour distribution and texture transformation may be strongly nonlinear, so a linear interpolation may introduce severe artifacts. Thus, this paper proposes two-variate quadratic interpolation to tackle this problem and demonstrates that it can be implemented in hardware. A software simulation and a VHDL description of the shading hardware are also presented.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116026925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945350
Jiří Bittner, V. Havran
Presents a series of simple improvements that make use of temporal and spatial coherence in the scope of hierarchical visibility algorithms. The hierarchy updating avoids visibility tests of certain interior nodes of the hierarchy. The visibility propagation algorithm reuses information about visibility of neighbouring spatial regions. Finally, the conservative hierarchy updating avoids visibility tests of the hierarchy nodes that are expected to remain visible. We evaluate the presented methods in the context of hierarchical visibility culling using occlusion trees.
{"title":"Exploiting temporal and spatial coherence in hierarchical visibility algorithms","authors":"Jiří Bittner, V. Havran","doi":"10.1109/SCCG.2001.945350","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945350","url":null,"abstract":"Presents a series of simple improvements that make use of temporal and spatial coherence in the scope of hierarchical visibility algorithms. The hierarchy updating avoids visibility tests of certain interior nodes of the hierarchy. The visibility propagation algorithm reuses information about visibility of neighbouring spatial regions. Finally, the conservative hierarchy updating avoids visibility tests of the hierarchy nodes that are expected to remain visible. We evaluate the presented methods in the context of hierarchical visibility culling using occlusion trees.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122046382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945358
M. Srámek
Volume graphics represents a set of techniques aimed at modeling, manipulation and rendering of objects represented by means of a 3D raster of elementary volume primitives-voxels. It represents a viable alternative for the standard surface graphics, and as such, it provides us with a possibility to overcome some of its bottlenecks and to extend its capabilities even further. Namely, by means of voxelization, it decouples object specific issues from rendering and enables uniform representation of all objects by a single primitive, the voxel. Thus, instead of dealing with a number of different objects with specific features, a renderer processes only one primitive object, which simplifies its architecture and leads to a more effective implementation. Moreover, rendering is independent on the original number of objects and hence a complete independence on object and scene complexity is achieved. Voxelization, i.e. a conversion of object representation by means of analytic formulas to the discrete 3D raster stands in the core of volume graphics techniques. We present and critically analyze distance oriented techniques as a tool for alias free volumetric representation of geometric objects.
{"title":"High precision non-binary voxelization of geometric objects","authors":"M. Srámek","doi":"10.1109/SCCG.2001.945358","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945358","url":null,"abstract":"Volume graphics represents a set of techniques aimed at modeling, manipulation and rendering of objects represented by means of a 3D raster of elementary volume primitives-voxels. It represents a viable alternative for the standard surface graphics, and as such, it provides us with a possibility to overcome some of its bottlenecks and to extend its capabilities even further. Namely, by means of voxelization, it decouples object specific issues from rendering and enables uniform representation of all objects by a single primitive, the voxel. Thus, instead of dealing with a number of different objects with specific features, a renderer processes only one primitive object, which simplifies its architecture and leads to a more effective implementation. Moreover, rendering is independent on the original number of objects and hence a complete independence on object and scene complexity is achieved. Voxelization, i.e. a conversion of object representation by means of analytic formulas to the discrete 3D raster stands in the core of volume graphics techniques. We present and critically analyze distance oriented techniques as a tool for alias free volumetric representation of geometric objects.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114731659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945355
Jean-Marc Cieutat, J. Gonzato, P. Guitton
The market for maritime training simulators is as important as the market for aeronautical training simulators. Many maritime accidents are caused by piloting errors in critical situations. Such situations are usually due to the environment (waves and streams). Hence, the main challenge of a maritime simulator is to simulate this environment as accurately as possible and, more precisely, to simulate ocean waves. Nowadays, two kinds of wave simulation theories are being presented. Firstly, accurate models are being created by physicists, while in computer graphics, researchers are putting forward some simpler physically-based models in order to produce static photorealistic images. This paper describes a new, efficient, real-time model of wave propagation and shows its integration in a real maritime simulator.
{"title":"A new efficient wave model for maritime training simulator","authors":"Jean-Marc Cieutat, J. Gonzato, P. Guitton","doi":"10.1109/SCCG.2001.945355","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945355","url":null,"abstract":"The market for maritime training simulators is as important as the market for aeronautical training simulators. Many maritime accidents are caused by piloting errors in critical situations. Such situations are usually due to the environment (waves and streams). Hence, the main challenge of a maritime simulator is to simulate this environment as accurately as possible and, more precisely, to simulate ocean waves. Nowadays, two kinds of wave simulation theories are being presented. Firstly, accurate models are being created by physicists, while in computer graphics, researchers are putting forward some simpler physically-based models in order to produce static photorealistic images. This paper describes a new, efficient, real-time model of wave propagation and shows its integration in a real maritime simulator.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130290451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945342
M. Grabner
The paper addresses the problem of interactive visualization in the view-dependent simplification framework. A geomorphing algorithm for interpolation between different levels of detail is given. The interpolation parameter is derived from the screen-space geometric error instead of assigning a fixed transition time to the interpolation process. Furthermore, a hybrid frame rate control system is proposed. Frame time is predicted based on the average rendering time per triangle, reducing oscillation and overshooting. A set of experiments demonstrates the advantages of both methods.
{"title":"Smooth high-quality interactive visualization","authors":"M. Grabner","doi":"10.1109/SCCG.2001.945342","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945342","url":null,"abstract":"The paper addresses the problem of interactive visualization in the view-dependent simplification framework. A geomorphing algorithm for interpolation between different levels of detail is given. The interpolation parameter is derived from the screen-space geometric error instead of assigning a fixed transition time to the interpolation process. Furthermore, a hybrid frame rate control system is proposed. Frame time is predicted based on the average rendering time per triangle, reducing oscillation and overshooting. A set of experiments demonstrates the advantages of both methods.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124702404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945354
B. Schmitt, C. Schlick, A. Pasko, V. Adzhiev
The concept of solid texturing is extended in two directions: constructive modeling of space partitions for texturing and modeling of multi-dimensional textured objects called hypervolumes. A hypervolume is considered as a point set with attributes of both physical (density, temperature, etc.) and photometric (color, transparency, diffuse and specular reflections, etc.) nature. The point-set geometry and attributes are modeled independently using real-valued scalar functions of several variables. Each real-valued function defining the geometry or an attribute is evaluated in the given point by a procedure traversing a constructive tree structure with primitives in the leaves and operations in the nodes of the tree. This approach provides a framework for the modeling, texturing and visualization of 3D solids and time-dependent and multi-dimensional objects in a completely uniform manner. We introduced a special modeling language and implemented software tools supporting the proposed approach. The concept of constructive hypervolume textures is independent of the geometric representation. We provide examples of textured functional representation (F-Rep) and boundary representation (B-Rep) objects as illustrations.
{"title":"Texturing through constructive modeling","authors":"B. Schmitt, C. Schlick, A. Pasko, V. Adzhiev","doi":"10.1109/SCCG.2001.945354","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945354","url":null,"abstract":"The concept of solid texturing is extended in two directions: constructive modeling of space partitions for texturing and modeling of multi-dimensional textured objects called hypervolumes. A hypervolume is considered as a point set with attributes of both physical (density, temperature, etc.) and photometric (color, transparency, diffuse and specular reflections, etc.) nature. The point-set geometry and attributes are modeled independently using real-valued scalar functions of several variables. Each real-valued function defining the geometry or an attribute is evaluated in the given point by a procedure traversing a constructive tree structure with primitives in the leaves and operations in the nodes of the tree. This approach provides a framework for the modeling, texturing and visualization of 3D solids and time-dependent and multi-dimensional objects in a completely uniform manner. We introduced a special modeling language and implemented software tools supporting the proposed approach. The concept of constructive hypervolume textures is independent of the geometric representation. We provide examples of textured functional representation (F-Rep) and boundary representation (B-Rep) objects as illustrations.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124767875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945332
N. Magnenat-Thalmann, L. Moccozet
The paper aims at defining new challenging research topics related to human simulation and animation. Although virtual human modelling, animation and simulation aspects have now been widely studied, there remain many topics and applications that are still open for research. Among them, we propose a survey of the current status and the future directions of research topics and applications such as virtual cloning and population and crowd modelling, clothing simulation, communication and interaction with virtual humans thanks to emotional dialogue, avatars and autonomous virtual embodiments in an inhabited virtual environment for cultural heritage.
{"title":"Some new challenging research topics in human animation","authors":"N. Magnenat-Thalmann, L. Moccozet","doi":"10.1109/SCCG.2001.945332","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945332","url":null,"abstract":"The paper aims at defining new challenging research topics related to human simulation and animation. Although virtual human modelling, animation and simulation aspects have now been widely studied, there remain many topics and applications that are still open for research. Among them, we propose a survey of the current status and the future directions of research topics and applications such as virtual cloning and population and crowd modelling, clothing simulation, communication and interaction with virtual humans thanks to emotional dialogue, avatars and autonomous virtual embodiments in an inhabited virtual environment for cultural heritage.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114381525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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