A Texture‐Free Multi‐Scale Model for Surface‐Based Rendering of Knitted Fabrics

Abstract Knitted fabrics present unique challenges for realistic rendering due to their complicated structure and scale‐dependent appearance. Existing methods typically rely on explicit yarn geometry, which is computationally complex, or texture‐based representations that require heavy storage and precomputed maps. In this paper, we introduce the first texture‐free, surface‐based appearance model for knitted fabrics, in which stitches are represented parametrically as thick curves and mapped directly onto fabric meshes. This avoids explicit yarn or fiber geometry, yet preserves the characteristic 3D look of yarn‐based models. Unlike prior surface‐based approaches, our method produces realistic volumetric effects such as depth, parallax, and silhouette preservation. To achieve this, we propose a curvature‐aware parallax mapping technique that ensures coherent appearance at grazing angles. Furthermore, we extend the appearance model to a multi‐scale formulation that aggregates geometry and visibility over texture footprints and adjusts roughness parameters for stable far‐field rendering. Our model combines the efficiency and simplicity of surface‐based methods with the volumetric realism of fiber‐based models, reproducing characteristic knit effects such as 3D stitch structure in a multi‐scale manner without the complexity or storage cost of texture‐based approaches.