Objective On the basis of the STL file format being

applied to store the medical model data,the three-dimensional

visualization effect of the medical model can be enhanced by setting

the color of the different parts of the model. Methods The STL file

format represents object without any color in anatomical models. We

add color information in the reserved location of triangle

information,so the relations can be distinguished between different

components of anatomical model. In the process of partitioning

different components on the three-dimensional medical model,two-

dimensional screen boundaries of different components are mapped into

the three-dimensional model through establishing relationship between

two-dimensional screen coordinate and the three-dimensional model

coordinate. The join algorithm is employed to ensure the closure of

three-dimensional boundary. And an algorithm similar to the seed-

filling is applied to fill the color information of the area within

the boundaries. Results The model with color information can describe

the different components of the medical model more accurately,and

possesses better three-dimensional visualization effects. Conclusions

The boundary-partitioning and the area-filling algorithm can achieve

a three-dimensional model with areas colored,and the enhanced STL

file format can efficiently store colored three-dimensional medical

model data.