A Unit Area approach based method was presented as an alternative to the geometry-based modelling of solidification to determine the solidification isotherms of basic casting geometries. This method was applied to square external corners, rectangular casting sections, sections of cylinders, discs, spheres and internal corners. Adequate solutions for these basic casting sections were obtained by using Unit Area based modelling. The results for the square external corners and rectangular casting sections, internal corners and "T" type casting sections showed a good correlation with Section-Modulus and modified Section-Modulus based methods. UnitArea based alternative method is significantly expressing the solidification behaviour of basic casting geometries without any modification.