Abstract: In Additive Manufacturing (AM) filed,the traditional STL file format contains only geometric information,without any materials information.Therefore,it cannot be applied to fabricate multiple material parts.Aiming to solve this problem,presents a new multiple material file format for additive manufacturing,MMS format.In this format,material index is introduced to identify material type of each region (such as basic material and functionally graded material),meanwhile material distribution function is used to describe material distribution in spatial regions.Moreover,the surface color information is added to multiple material model.Some cases verify that the proposed file format can be used to represent the multi-material model,and slice layer contains material information,which can be applied for additive manufacturing.

Key words: additive manufacturing, multiple material model, STL format, file format, geometric attribution, material attribution, color information