Implicit surface is a well-known surface representation. Geometric details of an object can be represented using less surface primitives than other representations such as polygonal meshes. In this paper, we propose a fast and a direct rendering method of SLIM (Sparse Low-degree IMplicit) surfaces using recent programmable GPUs. Our approach establishes a direct rendering of implicit surfaces based on the ray casting approach. Geometric processes such as an intersection between a ray and an implicit surface and blending for PU (Partition of Unity) are performed in the fragment program on GPUs. For large models, a hierarchical structure of a SLIM surface can be used for LOD rendering or view frustum culling to speed up the rendering. We demonstrate that highly parallel processing using GPUs enables efficient rendering of implicit surfaces.
隐式曲面是一种众所周知的曲面表示形式。物体的几何细节可以用比多边形网格等其他表示方式更少的表面基元来表示。在本文中，我们提出了一种快速和直接的SLIM(稀疏低次隐式)曲面绘制方法。我们的方法建立了基于光线投射方法的隐式表面的直接渲染。在图形处理器上的碎片程序中完成了射线与隐式曲面的交点和PU (Partition of Unity)的混合等几何处理。对于大型模型，SLIM表面的分层结构可用于LOD渲染或视图截锥体剔除以加快渲染速度。我们证明了使用gpu的高度并行处理可以有效地渲染隐式表面。
{"title":"GPU-based rendering of sparse low-degree implicit surfaces","authors":"T. Kanai, Y. Ohtake, H. Kawata, K. Kase","doi":"10.1145/1174429.1174455","DOIUrl":"https://doi.org/10.1145/1174429.1174455","url":null,"abstract":"Implicit surface is a well-known surface representation. Geometric details of an object can be represented using less surface primitives than other representations such as polygonal meshes. In this paper, we propose a fast and a direct rendering method of SLIM (Sparse Low-degree IMplicit) surfaces using recent programmable GPUs. Our approach establishes a direct rendering of implicit surfaces based on the ray casting approach. Geometric processes such as an intersection between a ray and an implicit surface and blending for PU (Partition of Unity) are performed in the fragment program on GPUs. For large models, a hierarchical structure of a SLIM surface can be used for LOD rendering or view frustum culling to speed up the rendering. We demonstrate that highly parallel processing using GPUs enables efficient rendering of implicit surfaces.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129695217","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}
We present a new approach for dynamic LOD processing for geometry images (GIs) in the graphics processing unit (GPU). A GI mipmap is constructed from a scanned 3D model, then a mipmap selector map is created from the camera position's information and the GI-mipmap. Using the mipmap selector map and the current camera position, some parts of the GI mipmap are discarded using a one-pass shader program that selects the mipmap level that must be displayed and calculates backface culling. Since our method does not require any extra spatial data structure, conceptually it is very simple. Since LOD selection is a one pass algorithm performed on the GPU, it is also fast.
{"title":"Simple dynamic LOD for geometry images","authors":"Benjamín Hernández, Isaac Rudomín","doi":"10.1145/1174429.1174454","DOIUrl":"https://doi.org/10.1145/1174429.1174454","url":null,"abstract":"We present a new approach for dynamic LOD processing for geometry images (GIs) in the graphics processing unit (GPU). A GI mipmap is constructed from a scanned 3D model, then a mipmap selector map is created from the camera position's information and the GI-mipmap. Using the mipmap selector map and the current camera position, some parts of the GI mipmap are discarded using a one-pass shader program that selects the mipmap level that must be displayed and calculates backface culling. Since our method does not require any extra spatial data structure, conceptually it is very simple. Since LOD selection is a one pass algorithm performed on the GPU, it is also fast.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127653346","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}
Physically based global illumination rendering at interactive frame rates would enable users to navigate within complex virtual environments, such as archaeological models. These algorithms, however, are computationally too demanding to allow interactive navigation on current PCs. A technique based on image subsampling and spatiotemporal coherence among successive frames is exploited, while resorting to progressive refinement whenever there is available computing power. A physically based ray tracer (Radiance) is used to compute reflected radiance at the model's triangles vertices. Progressive refinement is achieved increasing the sampling frequency by subdividing certain triangles and requesting shading information for the resulting vertices. This paper proposes and evaluates different criteria for selecting which triangles to subdivide. A random criterium and two criteria based on Normalized Luminance Differences are evaluated: one operating on image space, the other on object space. Results, obtained with a model of an old roman town, show that the object space criterium is able to locate and represent visual discontinuities, such as shadows, and does so requiring less triangle subdivisions than the other two.
{"title":"Refinement criteria for high fidelity interactive walkthroughs","authors":"António Oliveira, Luís Paulo Santos, A. Proença","doi":"10.1145/1174429.1174505","DOIUrl":"https://doi.org/10.1145/1174429.1174505","url":null,"abstract":"Physically based global illumination rendering at interactive frame rates would enable users to navigate within complex virtual environments, such as archaeological models. These algorithms, however, are computationally too demanding to allow interactive navigation on current PCs. A technique based on image subsampling and spatiotemporal coherence among successive frames is exploited, while resorting to progressive refinement whenever there is available computing power. A physically based ray tracer (Radiance) is used to compute reflected radiance at the model's triangles vertices. Progressive refinement is achieved increasing the sampling frequency by subdividing certain triangles and requesting shading information for the resulting vertices. This paper proposes and evaluates different criteria for selecting which triangles to subdivide. A random criterium and two criteria based on Normalized Luminance Differences are evaluated: one operating on image space, the other on object space. Results, obtained with a model of an old roman town, show that the object space criterium is able to locate and represent visual discontinuities, such as shadows, and does so requiring less triangle subdivisions than the other two.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"155 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124338054","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}
Modelling and simulating natural phenomena are two of the hardest tasks in virtual reality environments, owed to the complexity of the calculations involved. This fact becomes even more important for phenomena that are caused by the varying index of refraction in a medium (like mirages or the distortion caused by fire). Although there are some works on this topic, they sacrifice physical accuracy for efficiency, using heuristic methods that might achieve interactive rates in the best cases but do no consider physical simulation. Non-linear media (with non-homogeneous index of refraction) are costly to simulate precisely.This paper presents several techniques for simulate the effect of non-linear media on light rays, simulating natural phenomena in a more reasonable time than previous works without losing physical correctness. This can be ensured by following the ray equation for numerically calculating the path of light. The presented optimization techniques are based on this resolution method. Flight or driving simulators, as well as other virtual reality environments, could greatly benefit from this work.
{"title":"Efficient physically-based simulation of non-linear media","authors":"A. Muñoz, D. Gutierrez, F. Serón","doi":"10.1145/1174429.1174446","DOIUrl":"https://doi.org/10.1145/1174429.1174446","url":null,"abstract":"Modelling and simulating natural phenomena are two of the hardest tasks in virtual reality environments, owed to the complexity of the calculations involved. This fact becomes even more important for phenomena that are caused by the varying index of refraction in a medium (like mirages or the distortion caused by fire). Although there are some works on this topic, they sacrifice physical accuracy for efficiency, using heuristic methods that might achieve interactive rates in the best cases but do no consider physical simulation. Non-linear media (with non-homogeneous index of refraction) are costly to simulate precisely.This paper presents several techniques for simulate the effect of non-linear media on light rays, simulating natural phenomena in a more reasonable time than previous works without losing physical correctness. This can be ensured by following the ray equation for numerically calculating the path of light. The presented optimization techniques are based on this resolution method. Flight or driving simulators, as well as other virtual reality environments, could greatly benefit from this work.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126311026","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}
In this paper, we propose a new scheme for digital watermarking of three-dimensional (3-D) triangle meshes. In order to insert and extract watermark signals, we generate triangle strips by traversing the 3-D mesh model. We split the strips into two groups. For the first groups we embed the watermark signal into vertex positions of the 3-D model in the spherical coordinate system, and for the second group, we embed the watermark in the vertex positions in the Cartesian coordinates system. In both cases, we apply masking operation for the watermark signal according to the variation of the host data along the traversed strips so that we can change the embedding strength adaptively, and reduce the visibility distortion of the data embedding. We test robustness of the watermarking scheme by embedding a random binary sequence and applying different attacks, such as additive random noise, compression by MPEG-4 SNHC, and affine transform.
{"title":"A new mixed spatial domain watermarking of three dimensional triangle mesh","authors":"M. Ashourian","doi":"10.1145/1174429.1174473","DOIUrl":"https://doi.org/10.1145/1174429.1174473","url":null,"abstract":"In this paper, we propose a new scheme for digital watermarking of three-dimensional (3-D) triangle meshes. In order to insert and extract watermark signals, we generate triangle strips by traversing the 3-D mesh model. We split the strips into two groups. For the first groups we embed the watermark signal into vertex positions of the 3-D model in the spherical coordinate system, and for the second group, we embed the watermark in the vertex positions in the Cartesian coordinates system. In both cases, we apply masking operation for the watermark signal according to the variation of the host data along the traversed strips so that we can change the embedding strength adaptively, and reduce the visibility distortion of the data embedding. We test robustness of the watermarking scheme by embedding a random binary sequence and applying different attacks, such as additive random noise, compression by MPEG-4 SNHC, and affine transform.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"215 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121974965","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}
Animated crowds are effective to increase realism in virtual reality applications. However, rendering crowds requires large computational power. In this paper, we present a technique suitable to render large crowds of characters that takes advantage of existing programmable graphics hardware. Impostors are used for low-detail representation, while pseudo-instancing is used for higher detail. A LOD map is used to select between both representations, based on a customizable threshold.
{"title":"Impostors and pseudo-instancing for GPU crowd rendering","authors":"Erik Millán, Isaac Rudomín","doi":"10.1145/1174429.1174436","DOIUrl":"https://doi.org/10.1145/1174429.1174436","url":null,"abstract":"Animated crowds are effective to increase realism in virtual reality applications. However, rendering crowds requires large computational power. In this paper, we present a technique suitable to render large crowds of characters that takes advantage of existing programmable graphics hardware. Impostors are used for low-detail representation, while pseudo-instancing is used for higher detail. A LOD map is used to select between both representations, based on a customizable threshold.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"R-31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126631521","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}
In the presented article we discuss and detail the general methodological approaches, the reconstruction strategies and the techniques that have been employed to achieve the 3D interactive real-time virtual visualization of the digitally restituted inhabited ancient sites of Aspendos and Pompeii, respectively simulated using a virtual and an augmented reality setup. More specifically, the two case studies to which we will refer to illustrate our general methodology concern the VR restitution of the Roman theatre of Aspendos in Turkey, visualized as it was in the 3rd century, and the on-site AR simulation of a digitally restored Thermopolium situated at the archeological site of Pompeii in Italy. In order to enhance both simulated 3D environments, either case study presents the inclusion of real time animated virtual humans which are re-enacting situations and activities that were typically performed in such sites during ancient times. Furthermore, the implemented modelling and illumination strategies, along with the design choices that were operated regarding both the preparation of the textured 3D models of the sites and the simulated virtual humans, and concerning their optimization in order to suit the needs of a real time interactive visualization, will be equally presented.
{"title":"Real-time animation of ancient Roman sites","authors":"N. Magnenat-Thalmann, A. Foni, Nedjma Cadi-Yazli","doi":"10.1145/1174429.1174432","DOIUrl":"https://doi.org/10.1145/1174429.1174432","url":null,"abstract":"In the presented article we discuss and detail the general methodological approaches, the reconstruction strategies and the techniques that have been employed to achieve the 3D interactive real-time virtual visualization of the digitally restituted inhabited ancient sites of Aspendos and Pompeii, respectively simulated using a virtual and an augmented reality setup. More specifically, the two case studies to which we will refer to illustrate our general methodology concern the VR restitution of the Roman theatre of Aspendos in Turkey, visualized as it was in the 3rd century, and the on-site AR simulation of a digitally restored Thermopolium situated at the archeological site of Pompeii in Italy. In order to enhance both simulated 3D environments, either case study presents the inclusion of real time animated virtual humans which are re-enacting situations and activities that were typically performed in such sites during ancient times. Furthermore, the implemented modelling and illumination strategies, along with the design choices that were operated regarding both the preparation of the textured 3D models of the sites and the simulated virtual humans, and concerning their optimization in order to suit the needs of a real time interactive visualization, will be equally presented.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116005113","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}
Monte Carlo is the only choice for a physically correct method to do global illumination in the field of realistic image rendering. Adaptive sampling is an appealing means to reduce noise, which is resulted from the general Monte Carlo global illumination algorithms. In this paper, we take advantage of fuzzy rule-based reasoning to achieve different refinement thresholds for different pixels in the synthesized image. The developed technique can do adaptive sampling elaborately and effectively. Extensive implementation results indicate that our novel method can achieve significantly better than classic ones. To our knowledge, this is the first application of the fuzzy inference to global illumination.
{"title":"Adaptive sampling based on fuzzy inference","authors":"Qing Xu, Lianping Xing, Wei Wang, M. Sbert","doi":"10.1145/1174429.1174482","DOIUrl":"https://doi.org/10.1145/1174429.1174482","url":null,"abstract":"Monte Carlo is the only choice for a physically correct method to do global illumination in the field of realistic image rendering. Adaptive sampling is an appealing means to reduce noise, which is resulted from the general Monte Carlo global illumination algorithms. In this paper, we take advantage of fuzzy rule-based reasoning to achieve different refinement thresholds for different pixels in the synthesized image. The developed technique can do adaptive sampling elaborately and effectively. Extensive implementation results indicate that our novel method can achieve significantly better than classic ones. To our knowledge, this is the first application of the fuzzy inference to global illumination.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116738455","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}
Kai Xu, Yueshan Xiong, Yanzhen Wang, Ke Tan, Guangyou Guo
In this paper, we develop a new feature preserving smoothing method for the irregular and coarse meshes reconstructed from 2D contours. To make the feature detecting robust, a new detecting algorithm using the continuity among adjacent contours is proposed. Then the original mesh is subdivided adaptively according to the detected geometric features and smoothed with isotropic method. With the help of that, our algorithm obtains not only the feature-preserving result of anisotropic methods but also the simple and stable process of isotropic ones. After smoothing, the resolution of mesh can be resumed by moving the vertices in the original mesh to the positions of their corresponding vertices in the smoothed adaptive mesh. For smoothing of contours-based reconstructed meshes, experimental results show that our method can smooth the meshes satisfactorily and preserve their geometric features much better than other implemented methods.
{"title":"A simple and stable feature-preserving smoothing method for contours-based reconstructed meshes","authors":"Kai Xu, Yueshan Xiong, Yanzhen Wang, Ke Tan, Guangyou Guo","doi":"10.1145/1174429.1174495","DOIUrl":"https://doi.org/10.1145/1174429.1174495","url":null,"abstract":"In this paper, we develop a new feature preserving smoothing method for the irregular and coarse meshes reconstructed from 2D contours. To make the feature detecting robust, a new detecting algorithm using the continuity among adjacent contours is proposed. Then the original mesh is subdivided adaptively according to the detected geometric features and smoothed with isotropic method. With the help of that, our algorithm obtains not only the feature-preserving result of anisotropic methods but also the simple and stable process of isotropic ones. After smoothing, the resolution of mesh can be resumed by moving the vertices in the original mesh to the positions of their corresponding vertices in the smoothed adaptive mesh. For smoothing of contours-based reconstructed meshes, experimental results show that our method can smooth the meshes satisfactorily and preserve their geometric features much better than other implemented methods.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"3 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116823468","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}
In the olden days, many tools and technologies require the usage of human power. Therefore, the technologies will be more efficient if more people cooperate to use them. This is in contrast with today's technologies, many of which are designed to be operated by one person only. This paper presents the initial phase of a project that concerns the design and development of a technology which creates a necessity for people to cooperate. By using such a technology in a public space, it is hoped that a sense of community, as defined by the traditional Malay ways, can be revived. A technology probe called 'Kelembai Walk', which will be used in a participatory design process, is developed based on Presumptive Design. 'Kelembai Walk' is a multimedia application that uses pestles and mortars as interface devices. It will be displayed in an educational exhibition.
{"title":"Kelembai walk: encouraging cooperative interaction via design","authors":"A. Baharin, Romiza Md. Nor","doi":"10.1145/1174429.1174459","DOIUrl":"https://doi.org/10.1145/1174429.1174459","url":null,"abstract":"In the olden days, many tools and technologies require the usage of human power. Therefore, the technologies will be more efficient if more people cooperate to use them. This is in contrast with today's technologies, many of which are designed to be operated by one person only. This paper presents the initial phase of a project that concerns the design and development of a technology which creates a necessity for people to cooperate. By using such a technology in a public space, it is hoped that a sense of community, as defined by the traditional Malay ways, can be revived. A technology probe called 'Kelembai Walk', which will be used in a participatory design process, is developed based on Presumptive Design. 'Kelembai Walk' is a multimedia application that uses pestles and mortars as interface devices. It will be displayed in an educational exhibition.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116199386","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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