There are many applications that demand large quantities of natural looking motion. It is difficult to synthesize motion that looks natural, particularly when it is people who must move. In this paper, we present a framework that generates human motions by cutting and pasting motion capture data. Selecting a collection of clips that yields an acceptable motion is a combinatorial problem that we manage as a randomized search of a hierarchy of graphs. This approach can generate motion sequences that satisfy a variety of constraints automatically. The motions are smooth and human-looking. They are generated in real time so that we can author complex motions interactively. The algorithm generates multiple motions that satisfy a given set of constraints, allowing a variety of choices for the animator. It can easily synthesize multiple motions that interact with each other using constraints. This framework allows the extensive re-use of motion capture data for new purposes.
{"title":"Interactive motion generation from examples","authors":"Okan Arikan, D.A. Forsyth","doi":"10.1145/566570.566606","DOIUrl":"https://doi.org/10.1145/566570.566606","url":null,"abstract":"There are many applications that demand large quantities of natural looking motion. It is difficult to synthesize motion that looks natural, particularly when it is people who must move. In this paper, we present a framework that generates human motions by cutting and pasting motion capture data. Selecting a collection of clips that yields an acceptable motion is a combinatorial problem that we manage as a randomized search of a hierarchy of graphs. This approach can generate motion sequences that satisfy a variety of constraints automatically. The motions are smooth and human-looking. They are generated in real time so that we can author complex motions interactively. The algorithm generates multiple motions that satisfy a given set of constraints, allowing a variety of choices for the animator. It can easily synthesize multiple motions that interact with each other using constraints. This framework allows the extensive re-use of motion capture data for new purposes.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116230354","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 describe a method for realistically animating ductile fracture in common solid materials such as plastics and metals. The effects that characterize ductile fracture occur due to interaction between plastic yielding and the fracture process. By modeling this interaction, our ductile fracture method can generate realistic motion for a much wider range of materials than could be realized with a purely brittle model. This method directly extends our prior work on brittle fracture [O'Brien and Hodgins, SIGGRAPH 99]. We show that adapting that method to ductile as well as brittle materials requires only a simple to implement modification that is computationally inexpensive. This paper describes this modification and presents results demonstrating some of the effects that may be realized with it.
本文描述了一种模拟普通固体材料(如塑料和金属)韧性断裂的逼真动画方法。塑性屈服与断裂过程的相互作用是塑性断裂的特征。通过对这种相互作用进行建模，我们的韧性断裂方法可以产生比纯脆性模型更广泛的材料的真实运动。该方法直接扩展了我们之前对脆性断裂的研究[O'Brien and Hodgins, SIGGRAPH 99]。我们表明，将这种方法应用于延性和脆性材料只需要一个简单的实现修改，这在计算上是廉价的。本文描述了这种改进，并给出了一些结果，证明了它可能实现的一些效果。
{"title":"Graphical modeling and animation of ductile fracture","authors":"James F. O'Brien, Adam W. Bargteil, J. Hodgins","doi":"10.1145/566570.566579","DOIUrl":"https://doi.org/10.1145/566570.566579","url":null,"abstract":"In this paper, we describe a method for realistically animating ductile fracture in common solid materials such as plastics and metals. The effects that characterize ductile fracture occur due to interaction between plastic yielding and the fracture process. By modeling this interaction, our ductile fracture method can generate realistic motion for a much wider range of materials than could be realized with a purely brittle model. This method directly extends our prior work on brittle fracture [O'Brien and Hodgins, SIGGRAPH 99]. We show that adapting that method to ductile as well as brittle materials requires only a simple to implement modification that is computationally inexpensive. This paper describes this modification and presents results demonstrating some of the effects that may be realized with it.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120890287","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}
Recently a breakthrough has occurred in graphics hardware: fixed function pipelines have been replaced with programmable vertex and fragment processors. In the near future, the graphics pipeline is likely to evolve into a general programmable stream processor capable of more than simply feed-forward triangle rendering.In this paper, we evaluate these trends in programmability of the graphics pipeline and explain how ray tracing can be mapped to graphics hardware. Using our simulator, we analyze the performance of a ray casting implementation on next generation programmable graphics hardware. In addition, we compare the performance difference between non-branching programmable hardware using a multipass implementation and an architecture that supports branching. We also show how this approach is applicable to other ray tracing algorithms such as Whitted ray tracing, path tracing, and hybrid rendering algorithms. Finally, we demonstrate that ray tracing on graphics hardware could prove to be faster than CPU based implementations as well as competitive with traditional hardware accelerated feed-forward triangle rendering.
{"title":"Ray tracing on programmable graphics hardware","authors":"Timothy J. Purcell, I. Buck, W. Mark, P. Hanrahan","doi":"10.1145/566570.566640","DOIUrl":"https://doi.org/10.1145/566570.566640","url":null,"abstract":"Recently a breakthrough has occurred in graphics hardware: fixed function pipelines have been replaced with programmable vertex and fragment processors. In the near future, the graphics pipeline is likely to evolve into a general programmable stream processor capable of more than simply feed-forward triangle rendering.In this paper, we evaluate these trends in programmability of the graphics pipeline and explain how ray tracing can be mapped to graphics hardware. Using our simulator, we analyze the performance of a ray casting implementation on next generation programmable graphics hardware. In addition, we compare the performance difference between non-branching programmable hardware using a multipass implementation and an architecture that supports branching. We also show how this approach is applicable to other ray tracing algorithms such as Whitted ray tracing, path tracing, and hybrid rendering algorithms. Finally, we demonstrate that ray tracing on graphics hardware could prove to be faster than CPU based implementations as well as competitive with traditional hardware accelerated feed-forward triangle rendering.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124170389","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}
Two deficiencies in the original Noise algorithm are corrected: second order interpolation discontinuity and unoptimal gradient computation. With these defects corrected, Noise both looks better and runs faster. The latter change also makes it easier to define a uniform mathematical reference standard.
{"title":"Improving noise","authors":"K. Perlin","doi":"10.1145/566570.566636","DOIUrl":"https://doi.org/10.1145/566570.566636","url":null,"abstract":"Two deficiencies in the original Noise algorithm are corrected: second order interpolation discontinuity and unoptimal gradient computation. With these defects corrected, Noise both looks better and runs faster. The latter change also makes it easier to define a uniform mathematical reference standard.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126416885","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 level set framework for implementing editing operators for surfaces. Level set models are deformable implicit surfaces where the deformation of the surface is controlled by a speed function in the level set partial differential equation. In this paper we define a collection of speed functions that produce a set of surface editing operators. The speed functions describe the velocity at each point on the evolving surface in the direction of the surface normal. All of the information needed to deform a surface is encapsulated in the speed function, providing a simple, unified computational framework. The user combines pre-defined building blocks to create the desired speed function. The surface editing operators are quickly computed and may be applied both regionally and globally. The level set framework offers several advantages. 1) By construction, self-intersection cannot occur, which guarantees the generation of physically-realizable, simple, closed surfaces. 2) Level set models easily change topological genus, and 3) are free of the edge connectivity and mesh quality problems associated with mesh models. We present five examples of surface editing operators: blending, smoothing, sharpening, openings/closings and embossing. We demonstrate their effectiveness on several scanned objects and scan-converted models.
{"title":"Level set surface editing operators","authors":"K. Museth, D. Breen, R. Whitaker, A. Barr","doi":"10.1145/566570.566585","DOIUrl":"https://doi.org/10.1145/566570.566585","url":null,"abstract":"We present a level set framework for implementing editing operators for surfaces. Level set models are deformable implicit surfaces where the deformation of the surface is controlled by a speed function in the level set partial differential equation. In this paper we define a collection of speed functions that produce a set of surface editing operators. The speed functions describe the velocity at each point on the evolving surface in the direction of the surface normal. All of the information needed to deform a surface is encapsulated in the speed function, providing a simple, unified computational framework. The user combines pre-defined building blocks to create the desired speed function. The surface editing operators are quickly computed and may be applied both regionally and globally. The level set framework offers several advantages. 1) By construction, self-intersection cannot occur, which guarantees the generation of physically-realizable, simple, closed surfaces. 2) Level set models easily change topological genus, and 3) are free of the edge connectivity and mesh quality problems associated with mesh models. We present five examples of surface editing operators: blending, smoothing, sharpening, openings/closings and embossing. We demonstrate their effectiveness on several scanned objects and scan-converted models.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130387597","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 present a general method for rapid prototyping of realistic character motion. We solve for the natural motion from a simple animation provided by the animator. Our framework can be used to produce relatively complex realistic motion with little user effort.We describe a novel constraint detection method that automatically determines different constraints on the character by analyzing the input motion. We show that realistic motion can be achieved by enforcing a small set of linear and angular momentum constraints. This simplified approach helps us avoid the complexities of computing muscle forces. Simpler dynamic constraints also allow us to generate animations of models with greater complexity, performing more intricate motions. Finally, we show that by learning a small set of key parameters that describe a character pose we can help a non-skilled animator rapidly create realistic character motion.
{"title":"Synthesis of complex dynamic character motion from simple animations","authors":"Karen Liu, Zoran Popovi´c","doi":"10.1145/566570.566596","DOIUrl":"https://doi.org/10.1145/566570.566596","url":null,"abstract":"In this paper we present a general method for rapid prototyping of realistic character motion. We solve for the natural motion from a simple animation provided by the animator. Our framework can be used to produce relatively complex realistic motion with little user effort.We describe a novel constraint detection method that automatically determines different constraints on the character by analyzing the input motion. We show that realistic motion can be achieved by enforcing a small set of linear and angular momentum constraints. This simplified approach helps us avoid the complexities of computing muscle forces. Simpler dynamic constraints also allow us to generate animations of models with greater complexity, performing more intricate motions. Finally, we show that by learning a small set of key parameters that describe a character pose we can help a non-skilled animator rapidly create realistic character motion.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131222743","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}
B. Cutler, Julie Dorsey, L. McMillan, Matthias Müller, Robert Jagnow
We present a procedural approach to authoring layered, solid models. Using a simple scripting language, we define the internal structure of a volume from one or more input meshes. Sculpting and simulation operators are applied within the context of the language to shape and modify the model. Our framework treats simulation as a modeling operator rather than simply as a tool for animation, thereby suggesting a new paradigm for modeling as well as a new level of abstraction for interacting with simulation environments.Capturing real-world effects with standard modeling techniques is extremely challenging. Our key contribution is a concise procedural approach for seamlessly building and modifying complex solid geometry. We present an implementation of our language using a flexible tetrahedral representation. We show a variety of complex objects modeled in our system using tools that interface with finite element method and particle system simulations.
{"title":"A procedural approach to authoring solid models","authors":"B. Cutler, Julie Dorsey, L. McMillan, Matthias Müller, Robert Jagnow","doi":"10.1145/566570.566581","DOIUrl":"https://doi.org/10.1145/566570.566581","url":null,"abstract":"We present a procedural approach to authoring layered, solid models. Using a simple scripting language, we define the internal structure of a volume from one or more input meshes. Sculpting and simulation operators are applied within the context of the language to shape and modify the model. Our framework treats simulation as a modeling operator rather than simply as a tool for animation, thereby suggesting a new paradigm for modeling as well as a new level of abstraction for interacting with simulation environments.Capturing real-world effects with standard modeling techniques is extremely challenging. Our key contribution is a concise procedural approach for seamlessly building and modifying complex solid geometry. We present an implementation of our language using a flexible tetrahedral representation. We show a variety of complex objects modeled in our system using tools that interface with finite element method and particle system simulations.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127799555","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}
Geometric transformations are most commonly represented as square matrices in computer graphics. Following simple geometric arguments we derive a natural and geometrically meaningful definition of scalar multiples and a commutative addition of transformations based on the matrix representation, given that the matrices have no negative real eigenvalues. Together, these operations allow the linear combination of transformations. This provides the ability to create weighted combination of transformations, interpolate between transformations, and to construct or use arbitrary transformations in a structure similar to a basis of a vector space. These basic techniques are useful for synthesis and analysis of motions or animations. Animations through a set of key transformations are generated using standard techniques such as subdivision curves. For analysis and progressive compression a PCA can be applied to sequences of transformations. We describe an implementation of the techniques that enables an easy-to-use and transparent way of dealing with geometric transformations in graphics software. We compare and relate our approach to other techniques such as matrix decomposition and quaternion interpolation.
{"title":"Linear combination of transformations","authors":"M. Alexa","doi":"10.1145/566570.566592","DOIUrl":"https://doi.org/10.1145/566570.566592","url":null,"abstract":"Geometric transformations are most commonly represented as square matrices in computer graphics. Following simple geometric arguments we derive a natural and geometrically meaningful definition of scalar multiples and a commutative addition of transformations based on the matrix representation, given that the matrices have no negative real eigenvalues. Together, these operations allow the linear combination of transformations. This provides the ability to create weighted combination of transformations, interpolate between transformations, and to construct or use arbitrary transformations in a structure similar to a basis of a vector space. These basic techniques are useful for synthesis and analysis of motions or animations. Animations through a set of key transformations are generated using standard techniques such as subdivision curves. For analysis and progressive compression a PCA can be applied to sequences of transformations. We describe an implementation of the techniques that enables an easy-to-use and transparent way of dealing with geometric transformations in graphics software. We compare and relate our approach to other techniques such as matrix decomposition and quaternion interpolation.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129350186","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 describe a system for animating flames. Stochastic models of flickering and buoyant diffusion provide realistic local appearance while physics-based wind fields and Kolmogorov noise add controllable motion and scale. Procedural mechanisms are developed for animating all aspects of flame behavior including moving sources, combustion spread, flickering, separation and merging, and interaction with stationary objects. At all stages in the process the emphasis is on total artistic and behavioral control while maintaining interactive animation rates. The final system is suitable for a high volume production pipeline.
{"title":"Structural modeling of flames for a production environment","authors":"Arnauld Lamorlette, N. Foster","doi":"10.1145/566570.566644","DOIUrl":"https://doi.org/10.1145/566570.566644","url":null,"abstract":"In this paper we describe a system for animating flames. Stochastic models of flickering and buoyant diffusion provide realistic local appearance while physics-based wind fields and Kolmogorov noise add controllable motion and scale. Procedural mechanisms are developed for animating all aspects of flame behavior including moving sources, combustion spread, flickering, separation and merging, and interaction with stationary objects. At all stages in the process the emphasis is on total artistic and behavioral control while maintaining interactive animation rates. The final system is suitable for a high volume production pipeline.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115895283","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 discuss a method for creating animations that allows the animator to sketch an animation by setting a small number of keyframes on a fraction of the possible degrees of freedom. Motion capture data is then used to enhance the animation. Detail is added to degrees of freedom that were keyframed, a process we call texturing. Degrees of freedom that were not keyframed are synthesized. The method takes advantage of the fact that joint motions of an articulated figure are often correlated, so that given an incomplete data set, the missing degrees of freedom can be predicted from those that are present.
{"title":"Motion capture assisted animation: texturing and synthesis","authors":"Katherine Pullen, C. Bregler","doi":"10.1145/566570.566608","DOIUrl":"https://doi.org/10.1145/566570.566608","url":null,"abstract":"We discuss a method for creating animations that allows the animator to sketch an animation by setting a small number of keyframes on a fraction of the possible degrees of freedom. Motion capture data is then used to enhance the animation. Detail is added to degrees of freedom that were keyframed, a process we call texturing. Degrees of freedom that were not keyframed are synthesized. The method takes advantage of the fact that joint motions of an articulated figure are often correlated, so that given an incomplete data set, the missing degrees of freedom can be predicted from those that are present.","PeriodicalId":197746,"journal":{"name":"Proceedings of the 29th annual conference on Computer graphics and interactive techniques","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116110448","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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