This paper presents a feature based volume decomposition approach for Hexahedral Mesh generation. In this approach, feature recognition techniques are introduced to determine decomposition features from a CAD model and the model is decomposed into sub-models, which become meshable or can be meshed by meshing algorithms in a computationally inexpensive manner. The feature recognition methods employed are convexity based and use topology and geometry information, which is generally available in BREP solid modelers. The procedure of feature decomposition is recursive: sub-models are further decomposed until either they are matched with appropriate meshing algorithms or no more decomposition features are detected. The code is designed and programmed for self-adaptation and error-tolerance to achieve high automation with complex geometry. The paper gives testing results for several complicated manufactured parts.