中文摘要：

随着我国城市土地立体利用程度的增大,迫切需要土地权利的纵向表达,三维地籍（不动产）空间单元可较好地解决该问题.针对当前三维空间数据模型较难描述不规则不动产单元的问题,提出一种基于凸壳的三维空间数据模型的构建方法.首先分别构建整个产权体的凸壳和凹边界的凸壳;然后进行求交取反,并重点对凸壳的生成算法进行了改进,得到该产权体的三维模型.实验结果表明,该方法适合对不规则三维不动产单元模型的自动构建,可方便进行面元和体元（四面体）之间的集成和转换,同时满足表面建模和空间分析的需要.

英文摘要：

With the rapid growth of the utilization of urban land in multiple spatial dimensions in China, from the surface of land parcels to the space below or above them, it is an urgent demand for the vertical expression of land rights. Due to the traditional 2D cadastre can hardly represent these complex land right, some recent researches focus on so-called 3D cadastre or 3D real estate unit. In view of the critical issue that the current 3D spatial data models are difficult to describe irregular real estate unit, a method of convex hull of 3D spatial data model was proposed. We built first the convex hull of the whole 3D unit and its concave boundary, and then got the rid of their intersection parts to obtain its 3D vector volume. We also improved the algorithm of convex hull. Our experiments show that the method is suitable for automatic construction of irregular 3D real estate units. Moreover, it can be easier to the integration and transformation between the surface and volume models of the 3D spatial unit.