FDM process is one of the additive manufacturing methods producing 3D parts made of polymers directly through semi-molten extruded material over the substrate and in the form of layer by layer. The peculiar merits such as simple processing, utilizing various spectrum of stable and durable polymeric materials, and manufacturing benchmark with intricate geometry accompanied by spending the lowest cost (comparing to previous additive manufacturing methods) make this process come to cynosure in recent years. However, one of the significant challenges of FDM process would be the difference in dimensional accuracy between the designed one through computer and the manufactured part in sundry sciences such as engineering and medicine. The target of this research is to ameliorate dimensional accuracy of the manufactured parts through FDM method in two scopes as error avoidance and error compensation attitudes. Error avoidance attitude scrutinizes the effect of two parameters as built orientation and contour width over the external and internal dimensions using designing and manufacturing the appropriate and precise benchmarks. The results revealed that the manufactured parts in 45 0 built orientation have the highest accuracy comparing to the one in 0 0 and 90 0 . The increase of contour width causes to accrete internal and external dimensional accuracy of the parts. In error compensation attitude, two diverse benchmarks were designed and manufactured. After carrying out the measurement, the error behavior of each benchmark was obtained and then the mathematical models of error prediction and compensation were presented separately. The presented mathematical models of error prediction have the possibilities of predicting and compensating errors for the parts with desired geometry. Tellingly, they are able to be used for other additive manufacturing processes. The results obtained from the evaluation of the mathematical models of error prediction of each benchmark illustrated that each benchmark was able to compensate error by the amount of 70% and 50%. Keywords : Additive manufacturing process, FDM process, error avoidance attitude, error compensation attitude, contour width, build orientatio