Part design and geometry directly affect the castability, with volume, surface area and the number of features being the most important attributes. If the design has
undercuts or interior cavities it decreases castability due to tooling complexity. Long thin sections in a design are hard to fill. Location of the mold's
parting line also affects castability, because a non-planar parting line also increases tooling complexity. If a design requires a high degree of accuracy, fine
surface finish or defect free surface it reduces the castability of the part.
Quantitative analysis The castability of a design can be partially quantitatively determined by the following three equations. Better castability is denoted by a larger number. :\frac{V_c}{V_b} Where Vc is the volume of the casting and Vb is the volume of the smallest box that the casting could fit in. :\frac{6(V_c)^{2/3}}{A_c} Where Vc is the volume of the casting and Ac is the surface area of the casting :\frac{1}{(1+n_f)^{0.5}} Where nf is the number of features (holes, pockets, slots, bosses, ribs, etc.) ==Material properties==