is a statistical method used to predict the overall variation in an assembly (a "stack-up") based on the tolerances of its individual components.
The RSS method is a simplified statistical approach to tolerance analysis. It assumes that the tolerances of the individual parts are independent of each other and follow a normal distribution. The RSS method calculates the total tolerance (or variation) of an assembly by taking the square root of the sum of the squares of the individual part tolerances. rss method tolerance analysis