Worked on CesiumGS/cesium, focusing on enhancing the correctness and stability of the quadtree rendering path. Addressed a subtle bug in QuadtreePrimitive by ensuring that each cached position object was distinct, preventing shared references that previously led to incorrect height calculations for clamped entities. This targeted fix improved rendering reliability and reduced UI inconsistencies related to height drift. The work required careful debugging of cache aliasing issues and a strong understanding of CesiumJS internals. Utilized JavaScript for both front end development and testing, demonstrating attention to memory safety and performance in a complex, performance-sensitive 3D tiling pipeline.