My character FBX plays perfectly in DCC tools, yet inside my C-based custom engine every animation explodes—bones shoot off, limbs scale unpredictably and the mesh tears apart. The issue is clearly in the way my engine parses or applies the skeleton data, not in the source file itself. Here’s what you’ll walk into • A lean, self-written renderer and animation module (C, OpenGL, Assimp + limited FBX-SDK calls). • One rigged character with walk, run and idle clips that demonstrate the incorrect bone transformations as soon as they are loaded. • A reproducible test scene and a build pipeline that compiles in seconds on Windows. What I need from you 1. Pinpoint why the bone matrices are wrong—be it incorrect bind-pose extraction, wrong matrix order, bad handedness or scale compensation. 2. Patch the loader / animator code so the FBX plays exactly like the reference video. 3. Provide clear comments on every line you touch and a short note describing the fix so I can maintain it later. Acceptance criteria • All three clips display without any bone “explosions” in both debug and release builds. • No regressions in skinning performance or existing features. • Your patch compiles cleanly with clang and MSVC-2022 in the provided CMake project. If you’ve wrestled with FBX quirks, inverse bind matrices, or axis conversions before, you’ll feel right at home. Let me know roughly how you’d approach the diagnosis, and I’ll get you the repo and sample assets right away. Using C and OpenGL