近年來，隨著電腦輔助設計與製造(CAD/CAM)技術的快速成長，機械零件幾何模型資料量日漸龐大。因此，一個有效率的機械零件幾何模型搜尋系統去協助使用者查尋或取出所要的3D幾何模型是重要的。機械零件幾何3D幾近模型資料，由於擁有局部微小特徵會產生許多三角網格，所以會大量增加機械零件3D模型的幾何資料。本研究發展一個允許查詢者以簡略的模型外形草圖為輸入，可以在機械零件幾何3D 模型資料庫中搜尋出符合查詢者期待的機械零件幾何3D 幾何模型。由於輸入之草圖資料遠少於機械零件幾何3D模型資料，其查尋或取出比對之困難度增加，發展啟發性幾何模型思考邏輯來過濾機械零件幾何3D模型的局部微小特徵，簡化模型資料結構，可增加比對容易度和增加運算速度。 在本研究中，草圖與機械零件幾何3D模型之比對搜尋，係先將機械零件幾何3D模型資料庫中的模型進行微小特徵的簡化與幾何重建，使得搜尋範圍可以減小。利用草圖的模型凹角特徵，找尋機械零件幾何3D模型的初始投影角度和初始投影圖後，利用計算出簡化的草圖模型幾何中心和機械零件幾何3D模型初始投影圖的幾何中心，將兩向量重疊以增加初比對的準確性。經過以上兩步驟後，再進行ICP演算法疊代計算比對，找出可能符合查詢者期待的3D 幾何模型。最後，將搜尋出的模型依較有可能符合查詢者期待之模型的順序排列，並顯現出3D幾何模型的外型。經由這些步驟，讓查詢者能順利的搜尋出所想要的3D幾何模型。 With the development of Computer Aided Design/Manufacture in recent years, the data of geometric models has been growing rapidly, how to build an efficient 3D model search engine become urgent. The slight characteristics in the 3D geometric model make increases the machine parts 3D model the geometry material. In this paper, subsequently cooperate with the searcher that use the way of sketch contour to proceed the data comparison, searcher for in the 3D model information bank conforms to the inquiry anticipation similar 3D geometric model. Because the data of sketch is the less than in the 3D geometric model, using the Heuristic Geometric Reasoning method to simplify the slight characteristics. In this research, First, we will reconstruct the partial small characteristic of the model, that is in the 3D model information bank; Then initial projection is obtained form geometric characteristics and finds the geometry center of the sketch and 3D model initial, let to overlap the geometry center because that can increase compares to accuracy; Following to discover possibly 3D geometry model by the ICP algorithm; Finally, show the possibly 3D geometry model originally the appearance. By way of these steps, Lets searcher can discover 3D geometry model, that are they wanted.
