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Julian Panetta

Assistant Professor

UC Davis

Biography

Julian Panetta is an Assistant Professor of Computer Science at University of California, Davis. His research interests lie primarily in the domain of physical simulation, geometry processing, and optimization-based inverse design for digital fabrication. He develops efficient computational techniques for designing physical objects that meet specific performance goals and can be directly brought into the real world using additive fabrication or CNC machines. He is especially motivated to invent algorithms empowering users to exploit these technologies’ currently untapped potentials for a broad range of applications, from professional, industrial settings to casual use.

Interests

  • Digital Fabrication
  • Physical Simulation
  • Inverse Problems

Education

  • PhD in Computer Science, 2017

    New York University

  • BS in Computer Science, 2010

    California Institute of Technology

Positions

  • Assistant Professor, 2020-

    University of California, Davis

  • Postdoc, 2017-2020

    École Polytechnique Fédérale de Lausanne

Publications

Computational Homogenization for Inverse Design of Surface-based Inflatables

We develop an effcient homogenization technique for analyzing the contractions and stiffnesses of periodic inflatable patterns and use it for inverse design of general surface-based inflatables.

A Neural-Preconditioned Poisson Solver for Mixed Dirichlet and Neumann Boundary Conditions

We introduce a neural-preconditioned iterative solver for Poisson equations with mixed boundary conditions.

Computational Design of Flexible Planar Microstructures

We design flexible microstructures that emulate desired elastic materials over finite regions of macrosopic strain space.

C-shells: Deployable Gridshells with Curved Beams

We introduce a computational pipeline for simulating and designing C-shells, deployable structures composed of beams with curved planar rest shapes.

Computational Exploration of Multistable Elastic Knots

We present an algorithmic approach to discover, study, and design multistable elastic knots, physical realizations of closed curves embedded in 3-space.

Shape from Release: Inverse Design and Fabrication of Controlled Release Structures

Objects with different shapes can dissolve in significantly different ways inside a solution. Predicting different shapes’ dissolution dynamics is an important problem especially in …

Efficient Layer-by-Layer Simulation for Topology Optimization

Topology optimization and additive manufacturing together enable the optimal design and direct fabrication of complex geometric parts with groundbreaking performance for diverse applications. However …

Umbrella Meshes: Elastic Mechanisms for Freeform Shape Deployment

We present a computational inverse design framework for a new class of volumetric deployable structures that have compact rest states and deploy into bending-active 3D target surfaces. Umbrella meshes …

Topology Optimization via Frequency Tuning of Neural Design Representations

By tuning the scale hyperparameter of a neural design representation based on a Fourier feature network, we can control the smoothness of designs without explicit smoothing filters.

Computational Inverse Design of Surface-based Inflatables

Fusing two sheets along parallel curves creates pockets that inflate into tubes and deform into a curved 3D shape; we optimize the fusing curve network to reproduce an input geometry.

Weaving with Curved Ribbons

We optimize the shapes of curved planar laser-cut ribbons that weave into faithful approximations of smooth free-form geometries.

Bistable Auxetic Surface Structures

We optimize patterns that, when cut into a flat rubber sheet, produce bistable auxetic metamaterials encoding curved target geometries.

A Low-Parametric Rhombic Microstructure Family for Irregular Lattices

New fabrication technologies have significantly decreased the cost of fabrication of shapes with highly complex geometric structure. One important application of complex fine-scale geometric …

X-Shell Pavilion: A Deployable Elastic Rod Structure

Our first-prize-winning pavilion for the IASS 2019 Pavilion Competition.

X-Shells: A New Class of Deployable Beam Structures

X-Shells are a new class of deployable structures formed by an ensemble of elastic beams coupled by rotational joints.

Rapid Deployment of Curved Surfaces via Programmable Auxetics

We program curved surfaces into flat sheets by optimizing a strain-limited auxetic metamaterial.

Worst-Case Stress Relief for Microstructures

We introduce an efficient worst-case analysis for periodic microstructures and use it to design robust microstructures.

Thesis: Fine-scale Structure Design for 3D Printing

My thesis develops tools for designing and analyzing objects that leverage the flexibility and resolution of 3D printing.

Fine-Scale Structure Design

This poster summaries our Elastic Textures paper and ongoing work on worst-case stress minimization.

Elastic Textures for Additive Fabrication

We design 3D-printable elastic metamaterials and use them to create deformable objects with single-material printers.

Worst-Case Structural Analysis

We introduce an efficient formulation for performing worst-case stress analysis (stress analysis for unknown loads).

Volumetric Basis Reduction for Global Seamless Parameterization of Meshes

We present an efficient method for generating seamless global parameterizations of meshes with millions of triangles.

Dynamic Landmarking for Surface Feature Identification and Change Detection

Given the large volume of images being sent back from remote spacecraft, there is a need for automated analysis techniques that can quickly identify interesting features in those images. Feature …

Change Detection in Mars Orbital Images Using Dynamic Landmarking

As of December 2009, there are more than 1,500,000 orbital images of Mars available on the Planetary Data System’s Imaging Node (from Mars Odyssey, Mars Express, Mars Global Surveyor, and Mars …

Automatic Landmark Identification in Mars Orbital Imagery

We have developed new methods for automatically identifying landmarks such as craters, gullies, dark slope streaks, and dust devil tracks in remote sensing imagery. These methods are based on …

Code

VoxelFEM

C++ library for high-performance topology optimization.

Inflatables

Simulation and inverse design for surface-based inflatables.

MeshFEM

C++ finite element library and mesh data structure.

ElasticRods

C++ simulation framework for elastic rods and X-Shells.

RotationOptimization

C++ library for optimizing with rotation variables.

Notes

Structural Analysis with Discrete Elastic Rods

Expressions for the stresses experienced by a discrete elastic rod and discussion of the forces/torques on X-Shell rivets.

Analytic Eigensystems for Isotropic Membrane Energies

This technical report derives analytical expressions for the eigenvalues and eigenmatrices of an isotropic membrane energy density.

Optimizing over Rotations

Gradients and Hessians for optimizing with rotation variables.

Planar Elastica

Analytical expression for the shape of a beam compressed at each end.

Derivative of the Polar Decomposition

Derives an expression for the derivative of the rotation and stretching part of the polar decomposition.

Material Derivative of Mean Curvature

Calculation of the material derivative of mean/summed curvature as a surface is advected by some velocity field.

"Local-Global" Material Optimization

Discussion and analysis of our Elastic Textures paper’s material optimization algorithm.

Polar Decomposition and the Closest Rotation

Derivation of the closest rotation matrix (in Frobenius norm) to a square matrix.