Proceedings of the 3rd international symposium on Non-photorealistic animation and rendering - NPAR '04, 2004
We describe a technique for generating cartoon style animations of smoke. Our method takes the ou... more We describe a technique for generating cartoon style animations of smoke. Our method takes the output of a physically-based simulator and uses it to drive particles that are rendered using a variant of the depth differences technique (originally used for rendering trees). Specific issues we address include the placement and evolution of primitives in the flow and the maintenance of temporal coherence. The results are visually simple, flicker-free animations that convey the turbulent, dynamic nature of the gas with simple outlines.
Photon-density estimation techniques are a popular choice for simulating light transport in scene... more Photon-density estimation techniques are a popular choice for simulating light transport in scenes with complicated geometry and materials. This class of algorithms can be used to accurately simulate inter-reflections, caustics, color bleeding, scattering in participating media, and subsurface scattering. Since its introduction, photon-density estimation has been significantly extended in computer graphics with the introduction of: specialized techniques that intelligently modify the positions or bandwidths to reduce visual error using a small ...
We explore the emerging application area of physics-based simulation for computer animation and v... more We explore the emerging application area of physics-based simulation for computer animation and visual special effects. In particular, we examine its parallelization potential and characterize its behavior on a chip multiprocessor (CMP). Applications in this domain model and simulate natural phenomena, and often direct visual components of motion pictures. We study a set of three workloads that exemplify the span and complexity of physical simulation applications used in a production environment: fluid dynamics, facial animation, and cloth simulation. They are computationally demanding, requiring from a few seconds to several minutes to simulate a single frame; therefore, they can benefit greatly from the acceleration possible with large scale CMPs.
The back and forth error compensation and correction (BFECC) method advects the solution forward ... more The back and forth error compensation and correction (BFECC) method advects the solution forward and then backward in time. The result is compared to the original data to estimate the error. Although inappropriate for parabolic and other non-reversible partial differential equations, it is useful for often troublesome advection terms. The error estimate is used to correct the data before advection raising the method to second order accuracy, even though each individual step is only first order accurate. In this paper, we rewrite the MacCormack method to illustrate that it estimates the error in the same exact fashion as BFECC. The difference is that the MacCormack method uses this error estimate to correct the already computed forward advected data. Thus, it does not require the third advection step in BFECC reducing the cost of the method while still obtaining second order accuracy in space and time. Recent work replaced each of the three BFECC advection steps with a simple first order accurate unconditionally stable semi-Lagrangian method yielding a second order accurate unconditionally stable BFECC scheme. We use a similar approach to create a second order accurate unconditionally stable MacCormack method.
... Parameter Estimation for Constitutive Models of Deformable Objects Aleka McAdams JohnAnderson... more ... Parameter Estimation for Constitutive Models of Deformable Objects Aleka McAdams JohnAnderson Andrew Selle Academic Mentor Industry Mentor Industry Mentor UCLA Pixar Animation Disney Animation ... [4] M. Kauer, V. Vuskovic, J. Dual, G. Szekely, and M. Bajka. ...
Modeling the geometry of solid materials cracking and shattering into elaborately shaped pieces i... more Modeling the geometry of solid materials cracking and shattering into elaborately shaped pieces is a painstaking task, which is often impractical to tune by hand when a large number of fragments are produced. In Walt Disney's animated feature film Bolt, cracking and shattering objects were prominent visual elements in a number of action sequences. We designed a system to facilitate
The back and forth error compensation and correction (BFECC) method advects the solution forward ... more The back and forth error compensation and correction (BFECC) method advects the solution forward and then backward in time. The result is compared to the original data to estimate the error. Although inappropriate for parabolic and other non-reversible partial differential equations, it is useful for often troublesome advection terms. The error estimate is used to correct the data before advection raising the method to second order accuracy, even though each individual step is only first order accurate. In this paper, we rewrite the ...
Hair simulation remains one of the most challenging aspects of creating virtual characters. Most ... more Hair simulation remains one of the most challenging aspects of creating virtual characters. Most research focuses on handling the massive geometric complexity of hundreds of thousands of interacting hairs. This is accomplished either by using brute force simulation or by reducing degrees of freedom with guide hairs. This paper presents a hybrid Eulerian/Lagrangian approach to handling both self and body
We present a method for generating art-directable volumetric effects, ranging from physically-acc... more We present a method for generating art-directable volumetric effects, ranging from physically-accurate to non-physical results. Our system mimics the way experienced artists think about volumetric effects by using an intuitive lighting primitive, and decoupling the modeling and shading of this primitive. To accomplish this, we generalize the physically-based photon beams method to allow arbitrarily programmable simulation and shading phases. This
We present a new algorithm for near-interactive simulation of skeleton driven, high resolution el... more We present a new algorithm for near-interactive simulation of skeleton driven, high resolution elasticity models. Our methodology is used for soft tissue deformation in character animation. The algorithm is based on a novel discretization of corotational elasticity over a hexahedral lattice. Within this framework we enforce positive definiteness of the stiffness matrix to allow efficient quasistatics and dynamics. In addition,
Proceedings of the 3rd international symposium on Non-photorealistic animation and rendering - NPAR '04, 2004
We describe a technique for generating cartoon style animations of smoke. Our method takes the ou... more We describe a technique for generating cartoon style animations of smoke. Our method takes the output of a physically-based simulator and uses it to drive particles that are rendered using a variant of the depth differences technique (originally used for rendering trees). Specific issues we address include the placement and evolution of primitives in the flow and the maintenance of temporal coherence. The results are visually simple, flicker-free animations that convey the turbulent, dynamic nature of the gas with simple outlines.
Photon-density estimation techniques are a popular choice for simulating light transport in scene... more Photon-density estimation techniques are a popular choice for simulating light transport in scenes with complicated geometry and materials. This class of algorithms can be used to accurately simulate inter-reflections, caustics, color bleeding, scattering in participating media, and subsurface scattering. Since its introduction, photon-density estimation has been significantly extended in computer graphics with the introduction of: specialized techniques that intelligently modify the positions or bandwidths to reduce visual error using a small ...
We explore the emerging application area of physics-based simulation for computer animation and v... more We explore the emerging application area of physics-based simulation for computer animation and visual special effects. In particular, we examine its parallelization potential and characterize its behavior on a chip multiprocessor (CMP). Applications in this domain model and simulate natural phenomena, and often direct visual components of motion pictures. We study a set of three workloads that exemplify the span and complexity of physical simulation applications used in a production environment: fluid dynamics, facial animation, and cloth simulation. They are computationally demanding, requiring from a few seconds to several minutes to simulate a single frame; therefore, they can benefit greatly from the acceleration possible with large scale CMPs.
The back and forth error compensation and correction (BFECC) method advects the solution forward ... more The back and forth error compensation and correction (BFECC) method advects the solution forward and then backward in time. The result is compared to the original data to estimate the error. Although inappropriate for parabolic and other non-reversible partial differential equations, it is useful for often troublesome advection terms. The error estimate is used to correct the data before advection raising the method to second order accuracy, even though each individual step is only first order accurate. In this paper, we rewrite the MacCormack method to illustrate that it estimates the error in the same exact fashion as BFECC. The difference is that the MacCormack method uses this error estimate to correct the already computed forward advected data. Thus, it does not require the third advection step in BFECC reducing the cost of the method while still obtaining second order accuracy in space and time. Recent work replaced each of the three BFECC advection steps with a simple first order accurate unconditionally stable semi-Lagrangian method yielding a second order accurate unconditionally stable BFECC scheme. We use a similar approach to create a second order accurate unconditionally stable MacCormack method.
... Parameter Estimation for Constitutive Models of Deformable Objects Aleka McAdams JohnAnderson... more ... Parameter Estimation for Constitutive Models of Deformable Objects Aleka McAdams JohnAnderson Andrew Selle Academic Mentor Industry Mentor Industry Mentor UCLA Pixar Animation Disney Animation ... [4] M. Kauer, V. Vuskovic, J. Dual, G. Szekely, and M. Bajka. ...
Modeling the geometry of solid materials cracking and shattering into elaborately shaped pieces i... more Modeling the geometry of solid materials cracking and shattering into elaborately shaped pieces is a painstaking task, which is often impractical to tune by hand when a large number of fragments are produced. In Walt Disney's animated feature film Bolt, cracking and shattering objects were prominent visual elements in a number of action sequences. We designed a system to facilitate
The back and forth error compensation and correction (BFECC) method advects the solution forward ... more The back and forth error compensation and correction (BFECC) method advects the solution forward and then backward in time. The result is compared to the original data to estimate the error. Although inappropriate for parabolic and other non-reversible partial differential equations, it is useful for often troublesome advection terms. The error estimate is used to correct the data before advection raising the method to second order accuracy, even though each individual step is only first order accurate. In this paper, we rewrite the ...
Hair simulation remains one of the most challenging aspects of creating virtual characters. Most ... more Hair simulation remains one of the most challenging aspects of creating virtual characters. Most research focuses on handling the massive geometric complexity of hundreds of thousands of interacting hairs. This is accomplished either by using brute force simulation or by reducing degrees of freedom with guide hairs. This paper presents a hybrid Eulerian/Lagrangian approach to handling both self and body
We present a method for generating art-directable volumetric effects, ranging from physically-acc... more We present a method for generating art-directable volumetric effects, ranging from physically-accurate to non-physical results. Our system mimics the way experienced artists think about volumetric effects by using an intuitive lighting primitive, and decoupling the modeling and shading of this primitive. To accomplish this, we generalize the physically-based photon beams method to allow arbitrarily programmable simulation and shading phases. This
We present a new algorithm for near-interactive simulation of skeleton driven, high resolution el... more We present a new algorithm for near-interactive simulation of skeleton driven, high resolution elasticity models. Our methodology is used for soft tissue deformation in character animation. The algorithm is based on a novel discretization of corotational elasticity over a hexahedral lattice. Within this framework we enforce positive definiteness of the stiffness matrix to allow efficient quasistatics and dynamics. In addition,
Uploads
Papers by Andrew Selle