First, we need to think about how to make the model. That is not surprising. But, that is most important thing. Without the map when we travel, it might lose our way. So, we have to make a draft for the paper mock-up. This draft is so sensitive. If you change a material thickness to use, you need to modify a draft because the model can be made from an accuracy of 1/100mm. How to make the model is not only for model but also for product. This way often gives manufacturing process a hint.
If you think over the way of making model, you can shorten your working hours and you can get the beautiful model.