Papers by Fernando de Goes


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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]

Accepted to ACM Transactions on Graphics


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