基于过渡面重构的CAD模型压缩算法

Compression of CAD models based on reconstruction of blending surfaces

提出一种基于过渡面重构的CAD模型压缩算法,将B样条逼近形式的过渡面重构为过渡参数表达形式,可有效精简所需的记录数据量.首先判断曲面边界是否是曲率线,以及是否存在某一方向上的边界线为圆弧并排除非过渡面.然后通过曲率线追踪得到曲面曲率线上的离散点,由离散点构造截面圆弧,由截面圆弧计算出过渡面参数.最后给出了模型压缩实验,结果表明该算法对于包含较多过渡面的模型,压缩率超过60%,压缩误差小于1×10-4.

An efficient CAD models compression method was presented based on blending surfaces reconstruction.The amount of data can be reduced by reconstruction blending surfaces from B spline form to parameter expression form.First,the non-blending surfaces were excluded if the boundary curves were not curvature curves,or no boundary curve was circular curve.Second,the distinct point sets on curvature curves by curvature tracing was obtain,and then construct section arcs from them.Third,the blending parameters were computed from section arcs.Finally,examples of model compression were given.The reuslts show that for the model which contains many blending surface,its compression ratio is more than 60% and compression error less that 1×10^-4.