As I said at the beginning I use Excel/VBA to generate Acad scripts, and Microstran data files, also control Multiframe and various other programs with automation interfaces. I basically use Excel/VBA for everything.

DaveC has also said he uses Excel to generate models for FEM software.

Such applications can involve a considerable amount of calculation, as well as time and effort to develop. But none of the calculations may have anything to do with presentation of such calculations. The CAD drawing presents the results of calculation. The FEM model can also provide graphical presentation of inputs and outputs.

Our benefactor (John Doyle) here, hasn't yet clarified what exactly he is looking for when he requests calculations.