A computer simulation method of assembling parts of a mechanical assembly has been developed by Deere & Company to statistically analyze tolerance stack-up of complex two-dimensional and three-dimensional assemblies. It is called Assembly Variation Simulation System (AVSS). AVSS offers a way to predict the impact of design tolerance and manufacturing variation on assembly quality of a John Deere Crawler Track Chain/Shoe Assembly. This method identified both the amount of variation relative to specifications and the percent contribution of the major contributors to the variation. In addition. AVSS has been used on a variety of other assembly applications. It is a proprietary system presently being marketed.