关键词: 三维CAD模型，视觉相似性，检索，形状匹配，近似度，基准库

Abstract: A comprehensive survey on the up-to-date retrieval methods for 3D CAl)models was presented. Due to the great differences in representations and retrieval algorithms between 3D CAD models and other general models, CAD models retrieval is divided into two hierarchies: visual-similarity-based retrieval and semanticfunctional-descriptions-based retrieval. Representations and algorithms of each hierarchy were discussed and analyzed systematically. Bench-marks and evaluations of 3D CAD model searching methods were summarised. Finally existing difficulties and future research were discussed.

Key words: 3D CAD models, Visual-similarity,Rctricval,Shape matching,Similarity,Bcnchmark