This paper presents a simple-to-use mechanism for the creation of complex smoothly shaped surface... more This paper presents a simple-to-use mechanism for the creation of complex smoothly shaped surfaces of any genus or topological type. The surfaces are specified through interpolated geometric constraints consisting of positions and, optionally, surface normals and surface curvatures. From a designer's point of view, this is a very natural way to specify a desired shape, whether free-form or technical. Nonlinear optimization techniques are then used to minimize a fairness functional based on the variation of curvature. This functional produces very high quality surfaces with predictable, intuitive behavior, while generating, where possible, simple shapes, such as cylinders, spheres, or tori, which are commonly used in geometric modeling. While easy to use, this optimization-based approach is computationally quite demanding. With more efficient optimization algorithms and with the ever increasing processing power available on every desk-top, the techniques described here will provide the basis for a new class of practical interactive geometric modeling tools.
Journal of Computing and Information Science in Engineering, 2002
Handling Tool Holder Collision in Optimal Tool Sequence Selection for 2.5-D Pocket Machining. [Jo... more Handling Tool Holder Collision in Optimal Tool Sequence Selection for 2.5-D Pocket Machining. [Journal of Computing and Information Science in Engineering 2, 345 (2002)]. Roshan M. D'Souza, Paul K. Wright, Carlo Séquin. Abstract. ...
Journal of Computing and Information Science in Engineering, 2003
We describe a new algorithm for making partially hollow layered parts with thin, dense walls of a... more We describe a new algorithm for making partially hollow layered parts with thin, dense walls of approximately uniform thickness, for faster build times and reduced material usage. We have implemented our algorithm and tested its output on a fused deposition modeling (FDM) machine, using separate build volumes for a loosely filled interior and a thin, solid, exterior wall. The build volumes are derived as Boolean combinations of slice contours and their offsets. The Booleans are efficiently calculated via OpenGL winding number rules and the offset contours are generated from robustly generated Voronoi diagrams of the slices. Our algorithm guarantees that the exterior surface of the final part will be of high quality with no gaps while still allowing an efficient build.
Over the last several years we have developed the Berkeley Solid Interchange Format (SIF) for lay... more Over the last several years we have developed the Berkeley Solid Interchange Format (SIF) for layered manufacturing data exchange. By building both design software that outputs SIF as well as manufacturing software that processes the SIF input files, we gained insights into the concerns of both sides of data exchange -insights which often led to major changes in successive versions of the format. In this paper, we share some of the most important lessons we learned (many of which are applicable to all geometric data exchange, not merely for layered manufacturing) and explain how they shaped SIF.
Proceedings of the first ACM symposium on Solid modeling foundations and CAD/CAM applications - SMA '91, 1991
We demonstrate the application of a novel equivalence between familar stereographic maps in three... more We demonstrate the application of a novel equivalence between familar stereographic maps in three dimensions and rational quadratic triangular B6zier surfaces ([16], [17]). The equivalence yields a geometric construction of B6zier surfaces that parametrize quadrics. Given implicit equations specifying and bounding a quadric surface, the construction produces a trimmed domain and B6zier surface that together evaluate to exactly the specified portion of the implicit quadric. We show that B6zier surfaces constructed in this manner are easily invertible.
Proceedings of the 1995 symposium on Interactive 3D graphics - SI3D '95, 1995
This paper describes a software framework to aid in designing and implementing convenient manipul... more This paper describes a software framework to aid in designing and implementing convenient manipulation behaviors for objects in a 3D virtual environment.
Proceedings of the 6th annual symposium on Computer architecture - ISCA '79, 1979
X-NODE is a single-chip VLSI processor to be realized in the mid 1980's and to be... more X-NODE is a single-chip VLSI processor to be realized in the mid 1980's and to be used as a building block for a tree-structured multiprocessor system (X-TREE). Three major trends influence the design of this processor: the continuing evolution of VLSI technology, the requirements for parallelism and communication in a multiprocessor system, and the need for better support of software
Proceedings of the 24th annual conference on Computer graphics and interactive techniques - SIGGRAPH '97, 1997
Manipulation in immersive virtual environments is difficult partly because users must do without ... more Manipulation in immersive virtual environments is difficult partly because users must do without the haptic contact with real objects they rely on in the real world to orient themselves and their manipulanda. To compensate for this lack, we propose exploiting the one real object every user has in a virtual environment, his body. We present a unified framework for virtual-environment interaction based on proprioception, a person's sense of the position and orientation of his body and limbs. We describe three forms of body-relative interaction:
25 years of the international symposia on Computer architecture (selected papers) - ISCA '98, 1998
The Reduced Instruction Set Computer (RISC) Project investigates an alternative to the general tr... more The Reduced Instruction Set Computer (RISC) Project investigates an alternative to the general trend toward computers with increasingly complex instruction sets: With a proper set of instructions and a corresponding architectural design, a machine with a high effective throughput can be achieved. The simplicity of the instruction set and addressing modes allows most instructions to execute in a single machine cycle, and the simplicity of each instruction guarantees a short cycle time. In addition, such a machine should have a much shorter design time.
... We do not currently handle a dynamic environment, but it could be incorporated if the moving ... more ... We do not currently handle a dynamic environment, but it could be incorporated if the moving ... presents new challenges not all of which have been solved by this prototype implementation. ... the height field constraint is maintained we can do incremental rendering in static frames ...
The number of polygons comprising interesting architectural models is many more than can be rende... more The number of polygons comprising interesting architectural models is many more than can be rendered at interactive frame rates. However, due to occlusion by opaque surfaces (e.g., walls), only a small fraction of atypical model is visible from most viewpoints.
A hierarchical MEMS synthesis and optimization architecture has been developed for MEMS design au... more A hierarchical MEMS synthesis and optimization architecture has been developed for MEMS design automation. The architecture integrates an object-oriented component library with a MEMS simulation tool and two levels of optimization: global genetic algorithms and local gradient-based refinement. An object-oriented data structure is used to represent hierarchical levels of elements in the design library and their connectivity. Additionally, all elements
Proceedings of the 20th annual conference on Computer graphics and interactive techniques - SIGGRAPH '93, 1993
Page 1. Adaptive Display Algorithm for Interactive Frame Rates During Visualization of Complex Vi... more Page 1. Adaptive Display Algorithm for Interactive Frame Rates During Visualization of Complex Virtual Environments Thomas A. Funkhouser and Carlo H. S´equin University of California at Berkeley z Abstract We describe an ...
Abstract A new technique for 2-dimensional layout compaction of integrated circuits is presented.... more Abstract A new technique for 2-dimensional layout compaction of integrated circuits is presented. After a traditional one-dimentional precompaction step, the size of the layout is further reduced with a technique that bears a strong similarity to the technique of'zone-refining'used in the purification of crystal ingots. Individual circuit components or small clusters of components are peeled off row by row from the precompacted layout, moved across an open zone, and reassembled at the other end of this zone in a denser ...
We present a novel parameterization-independent exposition of the thirdorder geometric behavior o... more We present a novel parameterization-independent exposition of the thirdorder geometric behavior of a surface point. Unlike existing algebraic expositions, our work produces an intuitive explanation of third-order shape, analogous to the principal curvatures and directions that describe secondorder shape. We extract four parameters that provide a quick and concise understanding of the third-order surface behavior at any given point. Our shape parameters are useful for easily characterizing different third-order surface shapes without having to use tensor algebra. Our approach generalizes to higher orders, allowing us to extract similarly intuitive parameters that fully describe fourth-and higher-order surface behavior.
This paper presents a carefully chosen curve blending scheme between circles, which is based on a... more This paper presents a carefully chosen curve blending scheme between circles, which is based on angles, rather than point positions. The result is a class of circle splines that robustly produce fair-looking G 2 -continuous curves without any cusps or kinks, even through rather challenging, sparse sets of interpolation points. With a simple reparameterization the curves can also be made C 2 -continuous. The same method is usable in the plane, on the sphere, and in 3D space. q
... First row: Korbin Van Dyke, Osamu Tomisawa, James Peek, Prof. David Patterson, Prof. Carlo S6... more ... First row: Korbin Van Dyke, Osamu Tomisawa, James Peek, Prof. David Patterson, Prof. Carlo S6quin, Peter Kess-ler; second row: Robert Sherburne, Manolis Katevenis, Prof. John Ousterhout, Ralph Campbell, Richard Piepho, Daniel Fitzpatrick. ...
This paper presents a simple-to-use mechanism for the creation of complex smoothly shaped surface... more This paper presents a simple-to-use mechanism for the creation of complex smoothly shaped surfaces of any genus or topological type. The surfaces are specified through interpolated geometric constraints consisting of positions and, optionally, surface normals and surface curvatures. From a designer's point of view, this is a very natural way to specify a desired shape, whether free-form or technical. Nonlinear optimization techniques are then used to minimize a fairness functional based on the variation of curvature. This functional produces very high quality surfaces with predictable, intuitive behavior, while generating, where possible, simple shapes, such as cylinders, spheres, or tori, which are commonly used in geometric modeling. While easy to use, this optimization-based approach is computationally quite demanding. With more efficient optimization algorithms and with the ever increasing processing power available on every desk-top, the techniques described here will provide the basis for a new class of practical interactive geometric modeling tools.
Journal of Computing and Information Science in Engineering, 2002
Handling Tool Holder Collision in Optimal Tool Sequence Selection for 2.5-D Pocket Machining. [Jo... more Handling Tool Holder Collision in Optimal Tool Sequence Selection for 2.5-D Pocket Machining. [Journal of Computing and Information Science in Engineering 2, 345 (2002)]. Roshan M. D'Souza, Paul K. Wright, Carlo Séquin. Abstract. ...
Journal of Computing and Information Science in Engineering, 2003
We describe a new algorithm for making partially hollow layered parts with thin, dense walls of a... more We describe a new algorithm for making partially hollow layered parts with thin, dense walls of approximately uniform thickness, for faster build times and reduced material usage. We have implemented our algorithm and tested its output on a fused deposition modeling (FDM) machine, using separate build volumes for a loosely filled interior and a thin, solid, exterior wall. The build volumes are derived as Boolean combinations of slice contours and their offsets. The Booleans are efficiently calculated via OpenGL winding number rules and the offset contours are generated from robustly generated Voronoi diagrams of the slices. Our algorithm guarantees that the exterior surface of the final part will be of high quality with no gaps while still allowing an efficient build.
Over the last several years we have developed the Berkeley Solid Interchange Format (SIF) for lay... more Over the last several years we have developed the Berkeley Solid Interchange Format (SIF) for layered manufacturing data exchange. By building both design software that outputs SIF as well as manufacturing software that processes the SIF input files, we gained insights into the concerns of both sides of data exchange -insights which often led to major changes in successive versions of the format. In this paper, we share some of the most important lessons we learned (many of which are applicable to all geometric data exchange, not merely for layered manufacturing) and explain how they shaped SIF.
Proceedings of the first ACM symposium on Solid modeling foundations and CAD/CAM applications - SMA '91, 1991
We demonstrate the application of a novel equivalence between familar stereographic maps in three... more We demonstrate the application of a novel equivalence between familar stereographic maps in three dimensions and rational quadratic triangular B6zier surfaces ([16], [17]). The equivalence yields a geometric construction of B6zier surfaces that parametrize quadrics. Given implicit equations specifying and bounding a quadric surface, the construction produces a trimmed domain and B6zier surface that together evaluate to exactly the specified portion of the implicit quadric. We show that B6zier surfaces constructed in this manner are easily invertible.
Proceedings of the 1995 symposium on Interactive 3D graphics - SI3D '95, 1995
This paper describes a software framework to aid in designing and implementing convenient manipul... more This paper describes a software framework to aid in designing and implementing convenient manipulation behaviors for objects in a 3D virtual environment.
Proceedings of the 6th annual symposium on Computer architecture - ISCA '79, 1979
X-NODE is a single-chip VLSI processor to be realized in the mid 1980's and to be... more X-NODE is a single-chip VLSI processor to be realized in the mid 1980's and to be used as a building block for a tree-structured multiprocessor system (X-TREE). Three major trends influence the design of this processor: the continuing evolution of VLSI technology, the requirements for parallelism and communication in a multiprocessor system, and the need for better support of software
Proceedings of the 24th annual conference on Computer graphics and interactive techniques - SIGGRAPH '97, 1997
Manipulation in immersive virtual environments is difficult partly because users must do without ... more Manipulation in immersive virtual environments is difficult partly because users must do without the haptic contact with real objects they rely on in the real world to orient themselves and their manipulanda. To compensate for this lack, we propose exploiting the one real object every user has in a virtual environment, his body. We present a unified framework for virtual-environment interaction based on proprioception, a person's sense of the position and orientation of his body and limbs. We describe three forms of body-relative interaction:
25 years of the international symposia on Computer architecture (selected papers) - ISCA '98, 1998
The Reduced Instruction Set Computer (RISC) Project investigates an alternative to the general tr... more The Reduced Instruction Set Computer (RISC) Project investigates an alternative to the general trend toward computers with increasingly complex instruction sets: With a proper set of instructions and a corresponding architectural design, a machine with a high effective throughput can be achieved. The simplicity of the instruction set and addressing modes allows most instructions to execute in a single machine cycle, and the simplicity of each instruction guarantees a short cycle time. In addition, such a machine should have a much shorter design time.
... We do not currently handle a dynamic environment, but it could be incorporated if the moving ... more ... We do not currently handle a dynamic environment, but it could be incorporated if the moving ... presents new challenges not all of which have been solved by this prototype implementation. ... the height field constraint is maintained we can do incremental rendering in static frames ...
The number of polygons comprising interesting architectural models is many more than can be rende... more The number of polygons comprising interesting architectural models is many more than can be rendered at interactive frame rates. However, due to occlusion by opaque surfaces (e.g., walls), only a small fraction of atypical model is visible from most viewpoints.
A hierarchical MEMS synthesis and optimization architecture has been developed for MEMS design au... more A hierarchical MEMS synthesis and optimization architecture has been developed for MEMS design automation. The architecture integrates an object-oriented component library with a MEMS simulation tool and two levels of optimization: global genetic algorithms and local gradient-based refinement. An object-oriented data structure is used to represent hierarchical levels of elements in the design library and their connectivity. Additionally, all elements
Proceedings of the 20th annual conference on Computer graphics and interactive techniques - SIGGRAPH '93, 1993
Page 1. Adaptive Display Algorithm for Interactive Frame Rates During Visualization of Complex Vi... more Page 1. Adaptive Display Algorithm for Interactive Frame Rates During Visualization of Complex Virtual Environments Thomas A. Funkhouser and Carlo H. S´equin University of California at Berkeley z Abstract We describe an ...
Abstract A new technique for 2-dimensional layout compaction of integrated circuits is presented.... more Abstract A new technique for 2-dimensional layout compaction of integrated circuits is presented. After a traditional one-dimentional precompaction step, the size of the layout is further reduced with a technique that bears a strong similarity to the technique of'zone-refining'used in the purification of crystal ingots. Individual circuit components or small clusters of components are peeled off row by row from the precompacted layout, moved across an open zone, and reassembled at the other end of this zone in a denser ...
We present a novel parameterization-independent exposition of the thirdorder geometric behavior o... more We present a novel parameterization-independent exposition of the thirdorder geometric behavior of a surface point. Unlike existing algebraic expositions, our work produces an intuitive explanation of third-order shape, analogous to the principal curvatures and directions that describe secondorder shape. We extract four parameters that provide a quick and concise understanding of the third-order surface behavior at any given point. Our shape parameters are useful for easily characterizing different third-order surface shapes without having to use tensor algebra. Our approach generalizes to higher orders, allowing us to extract similarly intuitive parameters that fully describe fourth-and higher-order surface behavior.
This paper presents a carefully chosen curve blending scheme between circles, which is based on a... more This paper presents a carefully chosen curve blending scheme between circles, which is based on angles, rather than point positions. The result is a class of circle splines that robustly produce fair-looking G 2 -continuous curves without any cusps or kinks, even through rather challenging, sparse sets of interpolation points. With a simple reparameterization the curves can also be made C 2 -continuous. The same method is usable in the plane, on the sphere, and in 3D space. q
... First row: Korbin Van Dyke, Osamu Tomisawa, James Peek, Prof. David Patterson, Prof. Carlo S6... more ... First row: Korbin Van Dyke, Osamu Tomisawa, James Peek, Prof. David Patterson, Prof. Carlo S6quin, Peter Kess-ler; second row: Robert Sherburne, Manolis Katevenis, Prof. John Ousterhout, Ralph Campbell, Richard Piepho, Daniel Fitzpatrick. ...
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Papers by Carlo H Séquin