How do you define the "weight" of a model? The bits in your computer weigh essentially nothing, except perhaps for those electrons involved in setting the corresponding bits in memory.
I'd suggest you place your computer on a bathroom scale before and after running your model. The difference will give you an estimate of the weight of your model. :)
Only kidding there. But if you want a better answer than that, you need to explain what you had in mind in your question.
