Jiayao Zhang 张嘉瑶
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Projects

A selection of production titles, self-directed engine work, and technical explorations across: real-time physics simulation, GPU compute, and ML-assisted content pipelines.

Star Citizen

Star Citizen · Cloud Imperium Games · Mar 2024 – Present

Live-service multiplayer space simulation on StarEngine — a proprietary C++ engine with a 100+ engineer codebase.

I own real-time physics simulation subsystems spanning:

- Articulated rigid-body dynamics (ragdolls, spacecraft, ground vehicles)

- Softbody and cloth simulation with sleep/wake stability handling

- Rope, cable, and constraint systems (pulley, winch, distance)

- Multi-body vehicle dynamics on a shared constraint solver

- Physics Time-Slice Async — time-sliced async spawn/despawn architecture eliminating frame spikes when hundreds of entities enter and leave a scene (analogous to parallel environment reset in RL training rollouts)

- Physics Inspector — internal tooling for introspection and benchmarking of physics edge cases

Squadron 42

Squadron 42 · Cloud Imperium Games · Mar 2024 – Present

Cinematic single-player campaign on StarEngine. Focus areas:

- Physics performance optimization — diagnose and eliminate frame-time regressions under heavy simulation load via Optick CPU/GPU profiling

- Deterministic physics systems for reproducing and fixing edge-case bugs

- SIMD vectorization (AVX/SSE) for performance-critical solver paths

- Multithreaded physics pipeline with lock-free data structures

- Solver-level debugging on softbody/cloth stability issues (warm-restart, sleep/wake, AABB culling)

Regularly collaborate with art, animation, and graphics teams to keep physics integration seamless while meeting AAA performance targets.

Fate Trigger

Fate Trigger · ByteDance Games · Oct 2022 – Dec 2023

Multiplayer online action title with production-grade AI-assisted content tooling and real-time neural rendering. Contributions:

- Synthetic data pipeline — Houdini + Blender + Unreal PCG pipeline for reconstructing Rendering/Physically Stable 3D Scenes

- ML Deformers deployment — neural-driven mesh deformation running in-engine at frame budget alongside Nanite

- Generative AI content authoring tools — Stable Diffusion integration, procedural texture generation, AI-assisted animation workflows

- Physics-aware mesh simplification plugin — patented method preserving both visual fidelity and simulation accuracy across PC and mobile platforms [Patent]

- Chaos vehicle system + Nanite integration; cross-platform performance tuning

Physics Engine

Physics Engine · "The Rest of My Life"

Personal project · self-directed

A from-scratch rigid-body physics engine built as a lifelong learning project — a way to internalize the mechanics of constraint solvers, contact resolution, and articulated dynamics from first principles. Implemented incrementally:

- Linear Complementarity Problem (LCP) solver — Gauss-Seidel iteration

- Constraint framework with pluggable constraint class hierarchy

- Rigid-body distance constraints

- Ragdoll articulated dynamics with warm-starting

- Penetration constraint resolution

- Manifold generation and contact caching

- Motors, movers, and joint drives

Multiplayer Shooter UE5

Multiplayer Shooter — UE5 End-to-End Build

Self-directed · UE5 C++

A full-cycle UE5 multiplayer FPS built from empty project to shipped package — a self-directed exercise in traversing the full engine stack:

- Custom C++ gameplay framework on UE5's actor/component model

- Client-server replication for weapons, movement, and damage

- Animation state machines for character locomotion and combat

- Physics-driven interactions and hit detection

- AI opponents with behavior trees

- Level design, lighting, and post-process authoring

- Full-cycle project shipping including packaging and finishing