Mold Design and Casting > Applying Shrinkage > Selecting the Shrinkage Formula
  
Selecting the Shrinkage Formula
You can specify a shrinkage ratio that is based upon the final geometry of the reference part once shrinkage is applied, or a precalculated shrinkage ratio that is based upon the original geometry of the part.
There are two formulae to calculate shrinkage (S stands for the shrinkage ratio):
1 + S—The shrinkage ratio is based upon the original geometry of the model. This is set as the default.
1/(1–S)—The shrinkage ratio is based upon the resulting geometry of the model.
If shrinkage is specified, a modification of the formula causes all the dimension values or scale values to be updated. For example, if shrinkage by dimension has been defined with the initial formula (1 + S), and if you change the formula to 1/(1–S), the model regenerates from the first affected feature, if the shrinkage is applied by dimension, or from the shrinkage by scale feature, if appropriate.