Hello, Iβm Changyong π±βπ
/
Publications
Search
Publications
κ°€λ¬λ¦¬ 보기
Search
Crack Nucleation & Propagation
β’
Two-field H design
: We separate the strain energy history into two independent fields:
β’
Radial surface paths
: At impact, 6 crack paths are seeded radially outward from the contact center (star pattern), with a low Z-component (z = 0.15) to keep paths near the bottom surface for immediate visibility
β’
AT2 phase-field PDE
: Variational damage model solved via Jacobi iteration. H_crack (5Γ H_ref) is seeded along existing crack paths as a boundary condition
Phase Field/Manifold-based Gaussian Splats Crack Simulation
Core Claim
Directly optimizing Chamfer Distance (CD) can produce
worse CD values than not optimizing it at all.
This is not a metric design problem β it is a
gradient-structural failure.
Why It Fails (3 Propositions)
β’
Prop 1.
The unique attractor of the forward CD gradient is many-to-one collapse β multiple source points converge to the same target point
β’
Prop 2.
The reverse (tβs) term provides nonzero gradient to at most 1 of k collapsed points β the remaining kβ1 are stuck in a zero-gradient deadlock
β’
Prop 3.
Local regularizers (repulsion, smoothness, DCD)
cannot alter cluster-level drift
β translational invariance guarantees pairwise forces cancel at the centroid
On the Structural Failure of Chamfer Distance in 3D Shape Optimization
1. Background & Motivation (Why?)
Commanding a robot to "cut the apple in half" is deceptively difficult.
β’
Physical Complexity:
Food deforms, fractures, and changes shape under pressure. Standard datasets for rigid bodies cannot capture these dynamics.
β’
Data Scarcity:
Collecting real-world data (e.g., slicing thousands of fruits) is expensive and dangerous. Previous simulations lacked physical accuracy regarding forces and friction.
β’
Quantitative Grounding:
Few existing models can understand and execute precise numerical instructions, such as "cut at the 30% mark from the right."
2. Key Solution: CulinaryCut & VLAP (How?)
CulinaryCut-VLAP: A Vision-Language-Action-Physics Framework for Food Cutting via a Force-Aware Material Point Method
1. Background & Motivation (Why?)
Traditional shape morphing techniques have suffered from a fundamental problem known as the
"Rendering Gap."
β’
Physics Simulation (MPM):
Efficient because it uses sparse particles, but it lacks sufficient surface detail for high-quality visuals.
β’
Rendering:
Typically requires dense surface information to display high-fidelity images.
β’
The Problem:
The process connecting these two domains was non-differentiable. This meant that rendering errors couldn't be used to correct or optimize the underlying physical motion.
2. Key Idea: PhysMorph-GS (How?)
The researchers proposed a new pipeline that establishes a
bidirectional coupling
between Differentiable MPM (Physics) and 3D Gaussian Splatting (Rendering).
Core Mechanisms
1)
Deformation-Aware Upsampling
β’
Instead of relying solely on the sparse
"Anchor Particles"
from the physics engine, the system generates virtual
"Child Particles"
specifically for rendering.
PhysMorph-GS: Differentiable Shape Morphing via Joint Optimization of Physics and Rendering Objectives
TVCG Teaser Video
:
Rendering results:
β’
Sphere to Bunny & Duck to Cow:
β’
D to Dragon:
A Differentiable Material Point Method Framework for Shape Morphing
β’
Abstract :
Rendering results:
β’
Sand particle example:
β’
Snow with Car:
β’
Primitive Rectangle (vs MPM):
MPM-Based Angular Animation of Particles using Polar Decomposition Theory
Describe
Lavaβs localization
with wax
β’
Use Numeric Animation for Real Data in Gen AI
Lava Simulation based on Wax