Bernd Bickel - Academia.edu (original) (raw)

Papers by Bernd Bickel

Research paper thumbnail of Throwable panoramic ball camera

SIGGRAPH Asia 2011 Emerging Technologies on - SA '11, 2011

Abstract Acquiring panoramic images using stitching takes a lot of time and moving objects may ca... more Abstract Acquiring panoramic images using stitching takes a lot of time and moving objects may cause ghosting. It is also difficult to obtain a full spherical panorama, because the downward picture cannot be captured while the camera is mounted on the tripod.

Research paper thumbnail of Subsurface scattering using splat-based diffusion in point-based rendering

Science China Information Sciences, 2010

Point-based graphics has gained much attention as an alternative to polygon-based approaches beca... more Point-based graphics has gained much attention as an alternative to polygon-based approaches because of its simplicity and flexibility. However, current point-based techniques do not provide a sufficient rendering quality for translucent materials such as human skin. In this paper, we propose a point-based framework with subsurface scattering of light, which is important to create the soft and semi-translucent appearance of human skin. To accurately simulate subsurface scattering in multilayered materials, we present splat-based diffusion to apply a linear combination of several Gaussian basis functions to each splat in object space. Compared to existing point-based approaches, our method offers a significantly improved visual quality in rendering human faces and provides a similar visual quality to polygon-based rendering using the texture space diffusion technique. We demonstrate the effectiveness of our approach in rendering scanned faces realistically.

Research paper thumbnail of Adaptive Simulation of Electrical Discharges

We present an adaptive animation method for elec- trical discharges. Electric discharges can be s... more We present an adaptive animation method for elec- trical discharges. Electric discharges can be simu- lated using the dielectric breakdown model. Reg- ular discretization of the governing Laplace equa- tion leads to huge equation systems, and the com- putational cost of solving the equations quickly be- comes prohibitive at high resolutions, especially for simulations in 3D. In contrast, our method

Research paper thumbnail of Computational Aspects of Fabrication (Dagstuhl Seminar 14361)}}

Research paper thumbnail of Computational design of inflatable deformable ballons

Research paper thumbnail of System and method for invariant-based normal estimation

Research paper thumbnail of Motion-Based Design of Mechanical Objects

Research paper thumbnail of Spin-it: optimizing moment of inertia for spinnable objects

Research paper thumbnail of Posture Guided Design Of Deformable Objects

Research paper thumbnail of Orthogonal slicing for additive manufacturing

Most additive manufacturing technologies work by layering, i.e. slicing the shape and then genera... more Most additive manufacturing technologies work by layering, i.e. slicing the shape and then generating each slice independently. This introduces an anisotropy into the process, often as different accuracies in the tangential and normal directions, but also in terms of other parameters such as build speed or tensile strength and strain. We model this as an anisotropic cubic element. Our approach then finds a compromise between modeling each part of the shape individually in the best possible direction and using one direction for the whole shape part. In particular, we compute an orthogonal basis and consider only the three basis vectors as slice normals (i.e. fabrication directions). Then we optimize a decomposition of the shape along this basis so that each part can be consistently sliced along one of the basis vectors. In simulation, we show that this approach is superior to slicing the whole shape in one direction, only. It also has clear benefits if the shape is larger than the build volume of the available equipment.

Research paper thumbnail of crdbrd: Shape fabrication by sliding planar slices

Research paper thumbnail of Designing inflatable structures

ACM Transactions on Graphics, 2014

ABSTRACT We propose an interactive, optimization-in-the-loop tool for designing inflatable struct... more ABSTRACT We propose an interactive, optimization-in-the-loop tool for designing inflatable structures. Given a target shape, the user draws a network of seams defining desired segment boundaries in 3D. Our method computes optimally-shaped flat panels for the segments, such that the inflated structure is as close as possible to the target while satisfying the desired seam positions. Our approach is underpinned by physics-based pattern optimization, accurate coarse-scale simulation using tension field theory, and a specialized constraint-optimization method. Our system is fast enough to warrant interactive exploration of different seam layouts, including internal connections, and their effects on the inflated shape. We demonstrate the resulting design process on a varied set of simulation examples, some of which we have fabricated, demonstrating excellent agreement with the design intent.

Research paper thumbnail of Data-driven simulation methods in computer graphics

ACM SIGGRAPH 2012 Posters on - SIGGRAPH '12, 2012

Abstract In recent years, various methods have been introduced to exploit pre-recorded data to im... more Abstract In recent years, various methods have been introduced to exploit pre-recorded data to improve the performance and/or realism of dynamic deformations, but their differences and similarities have not been adequately analyzed or discussed. So far, the proposed methods have been explored mainly in the research context. They have not been adopted by the computer graphics industry.

Research paper thumbnail of Processing and editing of faces using a measurement-based skin reflectance model

ACM SIGGRAPH 2006 Sketches on - SIGGRAPH '06, 2006

Research paper thumbnail of 3D-Printing Spatially Varying BRDFs

IEEE Computer Graphics and Applications, 2000

A new method fabricates custom surface reflectance and spatially varying bidirectional reflectanc... more A new method fabricates custom surface reflectance and spatially varying bidirectional reflectance distribution functions (svBRDFs). Researchers optimize a microgeometry for a range of normal distribution functions and simulate the resulting surface's effective reflectance. Using the simulation's results, they reproduce an input svBRDF's appearance by distributing the microgeometry on the printed material's surface. This method lets people print svBRDFs on planar samples with current 3D printing technology, even with a limited set of printing materials. It extends naturally to printing svBRDFs on arbitrary shapes.

Research paper thumbnail of Computational Aspects of Fabrication: Modeling, Design, and 3D Printing

IEEE Computer Graphics and Applications, 2000

ABSTRACT 3D printing is considered a disruptive technology with a potentially tremendous socioeco... more ABSTRACT 3D printing is considered a disruptive technology with a potentially tremendous socioeconomic impact. The three articles in this special issue illustrate how novel computer graphics approaches are advancing such digital fabrication.

Research paper thumbnail of Computational Design of Rubber Balloons

Computer Graphics Forum, 2012

ABSTRACT This paper presents an automatic process for fabrication-oriented design of custom-shape... more ABSTRACT This paper presents an automatic process for fabrication-oriented design of custom-shaped rubber balloons. We cast computational balloon design as an inverse problem: given a target shape, we compute an optimal balloon that, when inflated, approximates the target as closely as possible. To solve this problem numerically, we propose a novel physics-driven shape optimization method, which combines physical simulation of inflatable elastic membranes with a dedicated constrained optimization algorithm. We validate our approach by fabricating balloons designed with our method and comparing their inflated shapes to the results predicted by simulation. An extensive set of manufactured sample balloons demonstrates the shape diversity that can be achieved by our method. © 2012 Wiley Periodicals, Inc.

Research paper thumbnail of Texturing Internal Surfaces from a Few Cross Sections

Computer Graphics Forum, 2007

We introduce a new appearance-modeling paradigm for synthesizing the internal structure of a 3D m... more We introduce a new appearance-modeling paradigm for synthesizing the internal structure of a 3D model from photographs of a few cross-sections of a real object. When the internal surfaces of the 3D model are revealed as it is cut, carved, or simply clipped, we synthesize their texture from the input photographs. Our texture synthesis algorithm is best classified as a morphing technique, which efficiently outputs the texture attributes of each surface point on demand. For determining source points and their weights in the morphing algorithm, we propose an interpolation domain based on BSP trees that naturally resembles planar splitting of real objects. In the context of the interpolation domain, we define efficient warping and morphing operations that allow for real-time synthesis of textures. Overall, our modeling paradigm, together with its realization through our texture morphing algorithm, allow users to author 3D models that reveal highly realistic internal surfaces in a variety of artistic flavors.

Research paper thumbnail of Subsurface scattering in point-based rendering

Chinese Science Bulletin, 2010

Research paper thumbnail of SYSTEM AND METHOD FOR MESOSCOPIC GEOMETRY MODULATION

Research paper thumbnail of Throwable panoramic ball camera

SIGGRAPH Asia 2011 Emerging Technologies on - SA '11, 2011

Abstract Acquiring panoramic images using stitching takes a lot of time and moving objects may ca... more Abstract Acquiring panoramic images using stitching takes a lot of time and moving objects may cause ghosting. It is also difficult to obtain a full spherical panorama, because the downward picture cannot be captured while the camera is mounted on the tripod.

Research paper thumbnail of Subsurface scattering using splat-based diffusion in point-based rendering

Science China Information Sciences, 2010

Point-based graphics has gained much attention as an alternative to polygon-based approaches beca... more Point-based graphics has gained much attention as an alternative to polygon-based approaches because of its simplicity and flexibility. However, current point-based techniques do not provide a sufficient rendering quality for translucent materials such as human skin. In this paper, we propose a point-based framework with subsurface scattering of light, which is important to create the soft and semi-translucent appearance of human skin. To accurately simulate subsurface scattering in multilayered materials, we present splat-based diffusion to apply a linear combination of several Gaussian basis functions to each splat in object space. Compared to existing point-based approaches, our method offers a significantly improved visual quality in rendering human faces and provides a similar visual quality to polygon-based rendering using the texture space diffusion technique. We demonstrate the effectiveness of our approach in rendering scanned faces realistically.

Research paper thumbnail of Adaptive Simulation of Electrical Discharges

We present an adaptive animation method for elec- trical discharges. Electric discharges can be s... more We present an adaptive animation method for elec- trical discharges. Electric discharges can be simu- lated using the dielectric breakdown model. Reg- ular discretization of the governing Laplace equa- tion leads to huge equation systems, and the com- putational cost of solving the equations quickly be- comes prohibitive at high resolutions, especially for simulations in 3D. In contrast, our method

Research paper thumbnail of Computational Aspects of Fabrication (Dagstuhl Seminar 14361)}}

Research paper thumbnail of Computational design of inflatable deformable ballons

Research paper thumbnail of System and method for invariant-based normal estimation

Research paper thumbnail of Motion-Based Design of Mechanical Objects

Research paper thumbnail of Spin-it: optimizing moment of inertia for spinnable objects

Research paper thumbnail of Posture Guided Design Of Deformable Objects

Research paper thumbnail of Orthogonal slicing for additive manufacturing

Most additive manufacturing technologies work by layering, i.e. slicing the shape and then genera... more Most additive manufacturing technologies work by layering, i.e. slicing the shape and then generating each slice independently. This introduces an anisotropy into the process, often as different accuracies in the tangential and normal directions, but also in terms of other parameters such as build speed or tensile strength and strain. We model this as an anisotropic cubic element. Our approach then finds a compromise between modeling each part of the shape individually in the best possible direction and using one direction for the whole shape part. In particular, we compute an orthogonal basis and consider only the three basis vectors as slice normals (i.e. fabrication directions). Then we optimize a decomposition of the shape along this basis so that each part can be consistently sliced along one of the basis vectors. In simulation, we show that this approach is superior to slicing the whole shape in one direction, only. It also has clear benefits if the shape is larger than the build volume of the available equipment.

Research paper thumbnail of crdbrd: Shape fabrication by sliding planar slices

Research paper thumbnail of Designing inflatable structures

ACM Transactions on Graphics, 2014

ABSTRACT We propose an interactive, optimization-in-the-loop tool for designing inflatable struct... more ABSTRACT We propose an interactive, optimization-in-the-loop tool for designing inflatable structures. Given a target shape, the user draws a network of seams defining desired segment boundaries in 3D. Our method computes optimally-shaped flat panels for the segments, such that the inflated structure is as close as possible to the target while satisfying the desired seam positions. Our approach is underpinned by physics-based pattern optimization, accurate coarse-scale simulation using tension field theory, and a specialized constraint-optimization method. Our system is fast enough to warrant interactive exploration of different seam layouts, including internal connections, and their effects on the inflated shape. We demonstrate the resulting design process on a varied set of simulation examples, some of which we have fabricated, demonstrating excellent agreement with the design intent.

Research paper thumbnail of Data-driven simulation methods in computer graphics

ACM SIGGRAPH 2012 Posters on - SIGGRAPH '12, 2012

Abstract In recent years, various methods have been introduced to exploit pre-recorded data to im... more Abstract In recent years, various methods have been introduced to exploit pre-recorded data to improve the performance and/or realism of dynamic deformations, but their differences and similarities have not been adequately analyzed or discussed. So far, the proposed methods have been explored mainly in the research context. They have not been adopted by the computer graphics industry.

Research paper thumbnail of Processing and editing of faces using a measurement-based skin reflectance model

ACM SIGGRAPH 2006 Sketches on - SIGGRAPH '06, 2006

Research paper thumbnail of 3D-Printing Spatially Varying BRDFs

IEEE Computer Graphics and Applications, 2000

A new method fabricates custom surface reflectance and spatially varying bidirectional reflectanc... more A new method fabricates custom surface reflectance and spatially varying bidirectional reflectance distribution functions (svBRDFs). Researchers optimize a microgeometry for a range of normal distribution functions and simulate the resulting surface's effective reflectance. Using the simulation's results, they reproduce an input svBRDF's appearance by distributing the microgeometry on the printed material's surface. This method lets people print svBRDFs on planar samples with current 3D printing technology, even with a limited set of printing materials. It extends naturally to printing svBRDFs on arbitrary shapes.

Research paper thumbnail of Computational Aspects of Fabrication: Modeling, Design, and 3D Printing

IEEE Computer Graphics and Applications, 2000

ABSTRACT 3D printing is considered a disruptive technology with a potentially tremendous socioeco... more ABSTRACT 3D printing is considered a disruptive technology with a potentially tremendous socioeconomic impact. The three articles in this special issue illustrate how novel computer graphics approaches are advancing such digital fabrication.

Research paper thumbnail of Computational Design of Rubber Balloons

Computer Graphics Forum, 2012

ABSTRACT This paper presents an automatic process for fabrication-oriented design of custom-shape... more ABSTRACT This paper presents an automatic process for fabrication-oriented design of custom-shaped rubber balloons. We cast computational balloon design as an inverse problem: given a target shape, we compute an optimal balloon that, when inflated, approximates the target as closely as possible. To solve this problem numerically, we propose a novel physics-driven shape optimization method, which combines physical simulation of inflatable elastic membranes with a dedicated constrained optimization algorithm. We validate our approach by fabricating balloons designed with our method and comparing their inflated shapes to the results predicted by simulation. An extensive set of manufactured sample balloons demonstrates the shape diversity that can be achieved by our method. © 2012 Wiley Periodicals, Inc.

Research paper thumbnail of Texturing Internal Surfaces from a Few Cross Sections

Computer Graphics Forum, 2007

We introduce a new appearance-modeling paradigm for synthesizing the internal structure of a 3D m... more We introduce a new appearance-modeling paradigm for synthesizing the internal structure of a 3D model from photographs of a few cross-sections of a real object. When the internal surfaces of the 3D model are revealed as it is cut, carved, or simply clipped, we synthesize their texture from the input photographs. Our texture synthesis algorithm is best classified as a morphing technique, which efficiently outputs the texture attributes of each surface point on demand. For determining source points and their weights in the morphing algorithm, we propose an interpolation domain based on BSP trees that naturally resembles planar splitting of real objects. In the context of the interpolation domain, we define efficient warping and morphing operations that allow for real-time synthesis of textures. Overall, our modeling paradigm, together with its realization through our texture morphing algorithm, allow users to author 3D models that reveal highly realistic internal surfaces in a variety of artistic flavors.

Research paper thumbnail of Subsurface scattering in point-based rendering

Chinese Science Bulletin, 2010

Research paper thumbnail of SYSTEM AND METHOD FOR MESOSCOPIC GEOMETRY MODULATION