WATER: Watertight Tessellation for Real-Time Pixel-Accurate Rendering of Large-Scale Surfaces

Watertight tessellation is essential for real-time rendering of large-scale surfaces, particularly for Non-Uniform Rational B-Splines (NURBS) and Catmull-Clark Subdivision (CCS) surfaces. We present WATER, a software-based framework that delivers watertight, non-uniform tessellation with pixel-level accuracy at real-time frame rates. Unlike fixed-function hardware tessellation, WATER adopts a fully GPU-driven pipeline with cache-friendly design and novel algorithms, offering greater flexibility, scalability, and performance. Under our framework, a 2×–3× speedup over hardware tessellation is achieved for bi-3 Bézier surfaces, while bi-7 Bézier surfaces exhibit a 7×–11× improvement. Compared to ETER [Xiong et al. 2023], our method achieves 1.3×–2.1× faster rendering and 52%–72% lower memory usage under the same non-watertight uniform pattern. When enforcing watertightness, a moderate overhead of 23%–51% is incurred. With its advantages in quality, efficiency, and adaptability, WATER provides a compelling alternative for industrial-scale rendering tasks requiring watertightness.