This paper presents MidSurfer, a novel parameter-free method for extracting mid-surfaces from segmented volumetric data. The method generates uniformly triangulated, smooth meshes that accurately capture structural features. The process begins with the Ridge Field Transformation step that transforms the segmented input data, followed by the Mid-Polyline Extraction Algorithm that works on individual volume slices. Based on the connectivity of components, this step can result in either single or multiple polyline segments that represent the structural features. These segments form a coherent series, creating a backbone of regularly spaced points representing the mid-surface. Subsequently, we employ a Polyline Zipper Algorithm for triangulation that connects these polyline segments across neighboring slices, yielding a detailed triangulated mid-surface mesh. Results show that this method outperforms previous techniques in versatility, simplicity, and accuracy. Our approach is publicly available as a ParaView plugin at
https://github.com/kaust-vislab/MidSurfer.