Papers by Fernando de Goes


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FaceBaker: Baking Character Facial Rigs with Machine Learning

Sarah Radzihovsky, Fernando de Goes, Mark Meyer
June 2020

Character rigs are procedural systems that deform a character's shape driven by a set of rig-control variables. Film quality character rigs are highly complex and therefore computationally expensive and slow to evaluate. We present a machine learning method for approximating facial mesh deformations which reduces rig computations, increases longevity of ... more

Paper (PDF)

Video


Garment Refitting for Digital Characters

Fernando de Goes, Donald Fong, Meredith O'Malley
June 2020

We present a new technique to refit garments between characters of different shapes. Our approach is based on a novel iterative scheme that alternates relaxation and rebinding optimizations. In the relaxation step, we use affine-invariant coordinates in order to adapt the input 3D garment to the shape of a target ... more

Paper (PDF)

Video


Sculpt Processing for Character Rigging

Fernando de Goes, Patrick Coleman, Michael Comet, Alonso Martinez
June 2020

Pose-space sculpting is a key component in character rigging workflows used by digital artists to create shape corrections that fire on top of deformation rigs. However, hand-crafting sculpts one pose at a time is notoriously laborious, involving multiple cleanup passes as well as repetitive manual edits. In this work, we ... more

Paper (PDF)

Video


Discrete Differential Operators on Polygonal Meshes

Fernando de Goes, Andrew Butts, Mathieu Desbrun
April 2020

Geometry processing of surface meshes relies heavily on the discretization of differential operators such as gradient, Laplacian, and covariant derivative. While a variety of discrete operators over triangulated meshes have been developed and used for decades, a similar construction over polygonal meshes remains far less explored despite the prevalence of ... more

Paper (PDF)


Anisotropic Elasticity for Inversion-Safety and Element Rehabilitation

Theodore Kim, Fernando de Goes, Hayley Iben
July 2019

We present an analysis of anisotropic hyperelasticity, specifically transverse isotropy, that obtains closed-form expressions for the eigendecompositions of many common energies. We then use these to build fast and concise Newton implementations. We leverage our analysis in two separate applications. First, we show that existing anisotropic energies are not inversion-safe, ... more

Paper (PDF)

Video

Additional materials: [Anisotropy2019_supplement.pdf], [matlab.zip]


Sharp Kelvinlets: Elastic Deformations with Cusps and Localized Falloffs

Fernando de Goes, Doug L. James
July 2019

In this work, we present an extension of the regularized Kelvin-let technique suited to non-smooth, cusp-like edits. Our approach is based on a novel multi-scale convolution scheme that layers Kelvinlet deformations into a finite but spiky solution, thus offering physically based volume sculpting with sharp falloff profiles. We also show ... more

Paper (PDF)

Video

Additional materials: [code.zip]


Analytic Eigensystems for Isotropic Distortion Energies

Breannan Smith, Fernando de Goes, Theodore Kim
September 2018

Many strategies exist for optimizing non-linear distortion energies in geometry and physics applications, but devising an approach that achieves the convergence promised by Newton-type methods remains challenging. In order to guarantee the positive semi-definiteness required by these methods, a numerical eigendecomposition or approximate regularization is usually needed. In this paper, ... more

Paper (PDF)

Additional materials: [movie.mov], [Matlab.zip], [supplement.pdf]


Automating the Handmade: Shading Thousands of Garments for Coco

Byron Bashforth, Fernando de Goes, Jacob Kuenzel, Jake Merrell, Athena Xenakis
August 2018

Coco presented a challenge for the garment shading team. Firstly, the scale of the movie is significant with both the human and skeleton worlds filled with primary, secondary, and background characters. Secondly, the garments speak to a specific culture and our shading needed to be very detailed to ... more

Paper (PDF)


Patch-based Surface Relaxation

Fernando de Goes, William Sheffler, Michael Comet, Alonso Martinez, Aimei Kutt
August 2018

From rigging to post-simulation cleanups, surface relaxation is a widely used procedure in feature animation. Over the years, Pixar has experimented with several techniques for this task, mostly based on variants of Laplacian smoothing. Notably, none of existing approaches are suited to reproduce the patch layout of a baseline mesh. ... more

Paper (PDF)


Dynamic Kelvinlets: Secondary Motions based on Fundamental Solutions of Elastodynamics

Fernando de Goes, Doug L. James
May 2018

We introduce Dynamic Kelvinlets, a new analytical technique for real-time physically based animation of virtual elastic materials. Our formulation is based on the dynamic response to time-varying force distributions applied to an infinite elastic medium. The resulting displacements provide the plausibility of volumetric elasticity, the dynamics of compressive and shear ... more

Paper (PDF)

Video

Additional materials: [code.zip], [suppl.zip]

Available as Pixar Technical Memo #18-05


Stable Neo-Hookean Flesh Simulation

Breannan Smith, Fernando de Goes, Theodore Kim
December 2017

Non-linear hyperelastic energies play a key role in capturing the fleshy appearance of virtual characters. Real-world, volume-preserving biological tissues have Poisson's ratios near 1/2, but numerical simulation within this regime is notoriously challenging. In order to robustly capture these visual characteristics, we present a novel version of Neo-Hookean elasticity. Our ... more

Paper (PDF)

Video

Additional materials: [snh_code.tar.bz2], [stable_neo_hookean_supplement.pdf]

Errata: The expression for alpha on the last line of Page 4 contained a typo that we have fixed.


Regularized Kelvinlets: Sculpting Brushes based on Fundamental Solutions of Elasticity

Fernando de Goes, Doug L. James
May 2017

We introduce a new technique for real-time physically based volume sculpting of virtual elastic materials. Our formulation is based on the elastic response to localized force distributions associated with common modeling primitives such as grab, scale, twist, and pinch. The resulting brush-like displacements correspond to the regularization of fundamental solutions ... more

Paper (PDF)

Video: Regularized Kelvinlets

Video: Additional example with ~2M triangles

Additional materials: [multiScaleDerivation.pdf], [gradDerivation.pdf]

SIGGRAPH 2017

Available as Pixar Technical Memo #17-03


Optimal Voronoi Tessellations with Hessian-based Anisotropy

Max Budninskiy, Beibei Liu, Fernando de Goes, Yiying Tong, Pierre Alliez, Mathieu Desbrun
December 2016

This paper presents a variational method to generate cell complexes with local anisotropy conforming to the Hessian of any given convex function and for any given local mesh density. Our formulation builds upon approximation theory to offer an anisotropic extension of Centroidal Voronoi Tessellations which can be seen as a ... more

Paper (PDF)

Additional materials: [BLdG+16_SuppMat.pdf]

SIGGRAPH Asia 2016


Subdivision Exterior Calculus for Geometry Processing

Fernando de Goes, Mathieu Desbrun, Mark Meyer, Tony DeRose
April 2016

This paper introduces a new computational method to solve differential equations on subdivision surfaces. Our approach adapts the numerical framework of Discrete Exterior Calculus (DEC) from the polygonal to the subdivision setting by exploiting the refinability of subdivision basis functions. The resulting Subdivision Exterior Calculus (SEC) provides significant improvements in ... more

Paper (PDF)

Additional materials: [supplementalFigs.pdf], [supplemental.pdf]

SIGGRAPH 2016

Available as Pixar Technical Memo #16-01


Convolutional Wasserstein Distances: Efficient Optimal Transportation on Geometric Domains

Justin Solomon, Fernando de Goes, Gabriel Peyre, Marco Cuturi, Adrian Butscher, Andy Nguyen, Tao Du, Leonidas Guibas
August 2015

This paper introduces a new class of algorithms for optimization problems involving optimal transportation over geometric domains. Our main contribution is to show that optimal transportation can be made tractable over large domains used in graphics, such as images and triangle meshes, improving performance by orders of magnitude compared to ... more

Paper (PDF)

SIGGRAPH 2015


Vector Field Processing on Triangle Meshes

Fernando de Goes, Mathieu Desbrun, Yiying Tong
August 2015

While scalar fields on surfaces have been staples of geometry processing, the use of tangent vector fields has steadily grown in geometry processing over the last two decades: they are crucial to encoding directions and sizing on surfaces as commonly required in tasks such as texture synthesis, non-photorealistic rendering, digital ... more

Paper (PDF)

SIGGRAPH Courses 2016, SIGGRAPH Asia Courses 2015