Geometric tolerances are the result of variations in the shape

orientation or location of part features.Although geometric feature variations can also contribute significantly to the performance of an assembly and should be considered in any comprehensive analysis

most researches on assembly tolerance analysis have focused on dimensional tolerances without accounting for geometric variations in the assembly.So far

no complete tolerance analysis approach has been developed to include both dimensional and geometric tolerances.A new

generalized approach for including all the geometric feature variations in the tolerance analysis using a vector-loop-based assembly tolerance model is presented.It focuses on how to characterize geometric feature variations in the vector-loop-based assembly tolerance model.The characterization will be used to help combine the effects of all variations within an assembly in order to realize tolerance analysis of mechanical assemblies including geometric tolerances.A practical example is presented to demonstrate the effectiveness of the proposed method.