This was critical for consoles. On the Xbox 360, the SDK could run physics entirely in L2-cache-friendly blocks, avoiding expensive 512MB GDDR3 round-trips. While earlier Havok versions had ragdolls and vehicle physics, the 2010 2.0-r1 release polished several advanced systems to production-ready stability. 3.1 SPU Optimization (PlayStation 3) The headline feature. While Havok 2009 had experimental SPU support, 2.0-r1 made it deterministic . You could run broad-phase (sweep and prune) and narrow-phase (collision resolution) entirely on SPUs, leaving the PPU free for gameplay and rendering.
| Scenario | Object Count | Simulation Time (ms) | | :--- | :--- | :--- | | Simple ragdoll (15 rigid bodies) | 1 | 0.08 – 0.12 | | Vehicle with 4 rays | 1 vehicle + 100 static | 0.20 – 0.35 | | Explosion debris | 500 boxes (mass 0.5kg) | 1.5 – 2.2 | | Large destruction scene | 2000 small fragments | (near limit) | havok sdk 2010 2.0-r1
Solution: Many studios wrote custom hkShaple processing scripts for 3ds Max that welded vertices and triangulated before export. The -r1 release was deterministic only if you followed strict rules: no compiler fast-math flags ( /fp:precise on MSVC), no random uninitialized memory, and all constraints must use the same solver iteration count. Changing m_solverIterations from 4 to 5 on one platform would break replay validation. The "Pose" Crash A notorious bug: If a ragdoll's bones stretched beyond a threshold (e.g., character clipping through geometry), the inverse kinematics solver in hkpRagdollConstraint would produce NaNs (Not a Number). The SDK lacked robust NaN propagation; instead, it would crash deep inside the hkMath::sqrt SSE intrinsic. The fix: inserting hkMath::isFinite() checks before every constraint solve. 7. Migration Path: From 2010 2.0-r1 to Havok 2013+ For developers still maintaining a legacy codebase on this SDK, upgrading is a traumatic but necessary process. This was critical for consoles
Setting up environment variables ( HAVOK_SDK , HAVOK_LIB ) was manual. A misplaced HK_DEBUG vs HK_RELEASE define would link the wrong CRT libraries, causing mysterious heap corruption. 4.2 The Havok Visual Debugger (HVD) A standout feature still fondly remembered: The Havok Visual Debugger . This was a separate Windows application that connected to your running game via TCP/IP. | Scenario | Object Count | Simulation Time