Sergiy Migdalskiy

Principal AI, ML, Physics Engineer at Valve Software

Bellevue, Washington, United States

About

Principal ML, AI, Physics, Tools Programmer. Research, Development, Deployment, Optimization and Support of AI tools for Anti-Cheat/Anti-Abuse, Softbody physics simulation and Time-Traveling debuggers and features for games. Applied Mathematician with substantial game systems development experience. Co-author of "Game Physics Pearls" (2010), speaker at GDC (2014, 2015) Shipped Deadlock, CS2, Half-Life:Alyx (Valve, 2020), Dota2 (Valve, 2015), CS:GO (Valve, 2012), Portal 2 (Valve, 2011), Left 4 Dead 2 (Valve, 2009), Left 4 Dead (Valve, 2008), Uncharted: Drake's Fortune (Naughty Dog/Sony, 2007), Far Cry (Crytek/Ubisoft, 2004). Algorithmic, multithreaded and SIMD optimization; physics, collision, ragdoll, cloth and softbody simulation technology; animation, camera, main hero systems and various tools. Ported lots of code from Windows/x86 to PS/3 (SPU), Amd64/Win64, Unix. From Irix to Windows. From PPU to SPU. From IrisGL to OpenGL. Specialties: Software architecture. Xbox360, PS/3 (SPU) development, optimization. Math and Physics R&D. Porting and Optimization.

Experience

  • Valve corporation (Full-time · 18 yrs)
    • Principal AI, ML, Physics Engineer
      Feb 2024 - Present · 2 yrs 5 mos

      LLM/ML/AI model development, optimization and deployment Client-side Softbody Physics simulation and authoring tools. Time-travel debugger and game features for game and physics

    • Principal Physics Engineer
      Jul 2008 - May 2025 · 16 yrs 11 mos

      2018-2020: Half Life: Alyx Implemented industry-leading physics debugger tools and cutting edge high fidelity cloth simulation and authoring software. Worked on low-level performance optimization (SIMD, assembly, C++, Multithreaded algos) 2015-2018: CS:GO Enjoying working in the core team, independently deciding on, implementing and shipping high-impact features. Scalability: the master universe back-end server was limiting user base growth. I split out some CPU intensive services into a separate server to remove this as a product growth limiting factor. Anti-Cheat: Designed, implemented and shipped an innovative visibility checking algorithm with very low server CPU overhead. This disrupted and limited usability of wallhack cheats, improving the core user experience. Replay: One of the most useful learning tools for the new players is to see an immediate feedback on how they died, in the form of replay from the enemy's perspective. I implemented it as a network stream time-shifted replay feature in the engine, and as an end-user-facing feature in CS-GO. Shipped in 2015. 2014-Present: Dota2 Implemented new high performance physically based cloth system, backwards compatible with legacy cloth SFX system. Worked on the whole stack, from the tools to content compilation, to SIMD-optimized runtime. Implemented multiple generations of tools to author cloth. 2011: Portal 2 PS/3 port from PC. Specialized on SPU optimizations, moved critical low-level parts of the rendering engine to SPU, implemented SPU-RSX communication and synchronization, added FXAA to the game rendering pipeline 2009: Left 4 Dead 2 2008: Left 4 Dead Xbox360: assembly, VMX, multithreading, Source engine optimizations and game systems development PS/3: assembly, VMX, SPU, RSX(GPU), multithreading, Source engine porting and optimizations and game systems development. PC: algorithmic, SIMD, multithreaded optimizations, physics, cloth, softbody, animation and tools development, low-level networking

  • Senior Programmer at Naughty Dog, Inc
    Feb 2004 - Jun 2008 · 4 yrs 5 mos

    Shipped Uncharted: Drake's Fortune in 2007 Developed cross-platform physics, collision, ragdoll engine. Implemented and optimized a lot of code for SPU. Developed specific SPU optimization techniques for math-heavy code. Co-developed advanced distributed data pipeline and asset building tools. Was a single developer for months at Research stage of the project, making initial implementations of animation, camera and main hero control systems.

  • Senior Programmer at Crytek
    May 2002 - Feb 2004 · 1 yr 10 mos

    Shipped Far Cry in 2004 Developed tools and animation system (motion compression, advanced blending, SIMD skinning, realistic dynamic decals, etc.). Developed and supported plug-ins for 3DS Max and A|W Maya. Optimized character animation and renderer systems. Ported Far Cry to AMD x64 platform.

  • Senior Programmer at Validio Ukraine
    Jul 1999 - May 2002 · 2 yrs 11 mos

    Worked as Unix/Windows programmer in a large team of developers, consultants, mathematicians and business analysts. Developed custom business software and web server components. Developed music recognition algorithm. Implemented mission-critical distributed multi-platform spell-checker server www.spellchecker.net.

  • Research Assistant at National Technical University, Ukraine
    Nov 1996 - Jul 1999 · 2 yrs 9 mos

    Physical simulation algorithms R&D. Rigid platform motion to research and improve quality of platform dampers. Combat behavior modeling, tactics R&D. Economic modeling.