# Hongsin Sunwoo

> Software Engineer

Location: San Ramon, California, United States
Profile: https://flows.cv/hongsin

Gameplay and engine systems engineer with 20+ years of experience shipping multiplayer and cross-platform titles across PC, console, web, and mobile.

I specialize in gameplay systems and engine architecture across Unreal, Unity, and custom in-house engines. I remain deeply hands-on, building scalable gameplay systems and improving production workflows, with extensive live service experience.

## Work Experience
### Principal Software Engineer @ Riot Games
Jan 2021 – Present
2XKO (Fighting, PC & Consoles, UE4/UE5)
• Leading champion engineering for Jinx and Blitzcrank, contribute to early prototyping of unreleased champions, and deliver foundational gameplay systems including fuse mechanics, Versus mode, and pregame flow — owning both client and backend (Golang) implementation.
• Driving async asset loading initiatives to reduce gameplay hitches and improve player experience, and collaborate on micro-patching systems for live content delivery.
• Reduced character load time in the editor from 62s to 11s (~6x faster) by introducing custom serialization, significantly improving developer iteration speed.
• Led Unreal Engine 5 migration across gameplay, rendering, shaders, and build pipelines during active development.
• Implemented Niagara user parameter override plugin that enables 100+ chroma variations per champion without asset duplication, improving content scalability and production efficiency.
• Established replay tooling for gameplay debugging and issue reproduction, and built automated champion and stage performance testing with dashboard integration to enable continuous regression monitoring and maintain production stability.
• Extended Unreal pose blending limits at the engine level to enable extreme facial animation, enhancing champion expressiveness and readability.
• Led cross-team editor tooling efforts, designing and implementing developer-facing gameplay tools to accelerate content creation and debugging workflows.

### Lead Tools Engineer @ Striking Distance Studios
Jan 2021 – Jan 2021
The Callisto Protocol (Horror, PC & Consoles, UE4)
• Led gameplay automation testing in collaboration with external test engineers to improve regression coverage and production stability.
• Supported PS4 and Xbox One level streaming and console performance optimization efforts.

### Senior Tools Engineer @ Striking Distance Studios
Jan 2019 – Jan 2021
The Callisto Protocol (Horror, PC & Consoles - UE4)
• Established UE4 tooling standards and a validated asset pipeline, collaborating with content creators and engineers to resolve workflow bottlenecks while building automated asset, rendering, and performance validation systems, profiling, and debugging tools.
• Developed an OLAT (One Light at a Time) viewer to support Callisto BRDF development and material response validation under controlled lighting conditions.
• Extended UE4 Sequencer to support animation of layered material properties and engineered a DCC-to-UE4 cinematic pipeline for automated sequence generation.
• Built a Maya FBX exporter with Perforce integration to streamline DCC-to-engine asset and cinematic workflows.
• Extended Unreal Game Sync with AWS S3 integration to enable multi-site lighting data distribution.

### Director Of Engineering @ nWay Inc.
Jan 2014 – Jan 2019
Power Rangers: Battle for The Grid (Fighting, PC & Consoles – Unity)
• Led integration of PlayStation 4, Xbox One, and Nintendo Switch SDKs, delivering authentication, social systems, and DLC workflows.
• Reduced load times by 40% by restructuring asset packaging and load sequencing.
• Led a cross-system refactor eliminating runtime memory allocations during gameplay.
• Leveraged the in-game replay system to reproduce identical gameplay scenarios across platforms for consistent profiling and performance optimization.
• Partnered with engineering and production leadership to define technical direction and execution strategy, delivering the project within a 6-month production cycle.

Power Rangers: Legacy Wars (Action, Mobile – Unity)
• Prototyped and implemented a rollback netcode architecture, improving input latency handling and synchronization stability for competitive PvP combat.
• Implemented replay and spectator systems to support competitive features and live-service visibility.
• Designed and developed a data-driven patching system and tooling to enable rapid content updates without requiring full client releases.
• Established CI/CD infrastructure (Jenkins, HockeyApp) and built internal operational tooling to automate build, testing, distribution, and live service workflows.
• Authored and maintained technical design documentation, collaborating with production and QA teams to manage releases and resolve live issues.

ChronoBlade(Action RPG, Mobile - Unity)
• Led cross-regional engineering teams (USA, Korea, China) across gameplay and platform initiatives.
• Designed and implemented load-testing clients to validate backend scalability for 300K+ CCU.
• Created automated desync detection tooling to improve multiplayer simulation stability.
• Partnered with Netmarble(Korea) and Netease(China) to deliver localization, regional deployment, and ongoing live operations support.

### Senior Software Engineer @ nWay Inc.
Jan 2011 – Jan 2013
ChronoBlade(Online Action RPG, Web - Unity)
• Architected a fully custom animation state machine–driven combat framework and developed an in-house visual authoring tool, enabling designers to iterate and extend combo and skill systems without engineering intervention.
• Built a deterministic lock-step networking model with fixed-point simulation and collision systems to guarantee cross-platform consistency between Flash and Unity clients.
• Developed character parts customization pipeline and preview tooling.
• Established CI-driven asset pipeline and optimized gameplay systems for memory and load performance.

### Lead Software Engineer @ Pixelberry
Jan 2010 – Jan 2011
Fashion Street(SNG, Web - Unity)
• Developed player customization features including room placement/decor and clothing tiling systems with UI support.
• Implemented client-side networking and asset streaming systems to improve load time and runtime performance.
• Integrated Facebook and Cyworld SDKs for authentication, social features, and payment systems.

### Software Engineer @ Electronic Arts
Jan 2008 – Jan 2010
Battlefield Online(FPS, PC)
• Developed production tools for level, character, and AI workflows in collaboration with designers and artists.
• Implemented gameplay systems including tutorial and commander features.
• Contributed to DCC-to-engine integration via a Maya exporter plugin.

### Lead Software Engineer @ Mgame
Jan 2004 – Jan 2008
Warbane(MMORPG, PC)
• Architected and implemented a custom 3D game engine built on OGRE3D.
• Developed a world editor with Play-In-Editor support and integrated PathEngine for server-side navigation mesh export.
• Implemented seamless terrain rendering using texture splatting, shadow mapping, and static LOD systems.

Holic Online(MMORPG, PC)
• Built a shader-based rendering system using DirectX 9.
• Implemented skeletal animation, dynamic batching (grass/particles), and quad-tree spatial partitioning for rendering and collision.
• Developed 3ds Max exporter plugins for character and environment pipelines.

Ares Online(MMORPG, PC)
• Developed internal tools for designers and artists to streamline content creation.
• Implemented localization systems.
• Reduced build times from 2 minutes to 10 seconds by eliminating header dependencies and restructuring build configuration.


## Education
### Bachelor's degree in Computer Engineering
Ajou University


## Contact & Social
- LinkedIn: https://linkedin.com/in/hongsin-sunwoo

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Source: https://flows.cv/hongsin
JSON Resume: https://flows.cv/hongsin/resume.json
Last updated: 2026-04-12