1. A simulation method comprising: dividing a material surface into finite computational elements using a computer; and calculating a rate of one of deposition and etching at each of the computational elements to simulate a feature profile of the material surface using the computer, the calculating including calculating an indirect effect of a first computational element on the rate at a second computational element, the calculating the indirect effect including: correcting a surface profile at the first computational element on the basis of a surface structure around the first computational element using a level set method; and calculating the indirect effect on the basis of the corrected surface profile at the first computational element, wherein the correction of the surface profile includes approximating at least part of the surface profile at the first computational element to a curved surface which is continuous to the surface around the first computational element.