一种基于距离分区的BIM模型零水印算法

针对建筑信息模型（BIM）模型版权保护的问题，基于BIM的数据特征提出了一种BIM模型的零水印算法.首先，将不同数据中约束性不强的点图元排除，获得其他点图元的位置信息，计算单体模型的特征点到各个点图元的基准点之间的距离作为水印构造的载体；其次，将特征值进行排序，求出相邻点之间的变化率，将不符合要求的特征值排除；最后，根据特征值的特征对特征值分区，利用各分区中特征值的奇偶性构造一种用于BIM模型版权保护的零水印算法.实验结果证明，所提算法安全性高，可对常规攻击平移、旋转和模型详细程度的变化有较强的鲁棒性，能够满足实用性的需求，对BIM模型的版权保护有重要价值.

The Zero Watermarking Algorithm Based on Distance Partition for BIM Modeling

Aiming at the building information modeling (BIM) model copyright problem, basing on the BIM data characteristics, designs a zero watermarking algorithm for BIM data, which will not change data precision. Because different modeling has its own primitives and constraint relation, the proposed algorithm must be taking full account of the difference. Firstly, the lowly constraints of the primitive points are removing and the other primitive location points are obtaining. The distance between each point benchmark and the feature point is the carrier for watermarking by choosing the feature point of the monomer precise modeling. Secondly, the algorithm bubbles sort the eigenvalues and obtains the change rate of consecutive eigenvalues, then removing the high change rate eigenvalues. Finally, dividing the eigenvalues and construct a series of zero watermarking sequence. The results of experiment showed that the algorithm had strong robustness to usual attacking such as translation, rotation and slightly deleting point.