Abstract: The problem of dimensioning in variant design was studied.For the unreasonable problems of the relative position between dimensioning and model as well as between dimensioning,the dimension layout rule base,basic unit rule base and basic unit reference model rule base were established.According to relevant rule information of the basic unit rule base and basic unit reference model rule base,a dimensioning adjustment method based on the basic unit was used to solve the unreasonable problems of relative position between dimensioning and model.According to relevant rule information of the dimension layout rule base,the spatial constraint relationship between dimensions before model variant was established;a dimensioning adjustment method based on the constraint was used to solve the unreasonable problems of relative position between dimensioning.Finally,feasibility of the automatic adjustment method of the system dimensioning was verified taking the SolidWorks as the secondary development platform and gearbox output shaft as an example.

Key words: variant design, dimensioning, dimensioning adjustment, secondary development