Jumping in to add that the manufacturer makes adjustments for shrinkage based on material properties, thermal expansion effects, and moisture sensitivity. Shrinkage also depends on the geometric shape of a particular part: thin-walled sections usually shrink more than thick ones, and the presence of undercuts leads to non-uniform shrinkage. Furthermore, resin compositions can affect how much a part shrinks; hence, it is important to consult with your manufacturer regarding material choices. Given these factors, and by delineating explicit tolerances that have been set, one ensures that part dimensions are maintained according to specifications. Always reconfirm how shrinkage is handled with your manufacturer beforehand.