For every product to be converted into a tangible solution, one also needs to understand material properties, their use, manufacturing and tooling. And again the way to develop can be both using craft design and/or mechanized production. For each to be understood, one also needs to understand material sources and impact.
 
My take on the IB Curriculum Structure:
If you see the IB curriculum, you will find that the way I have put together the chapters, they differ in order. This is because this is the best way (I feel) to teach Design Technology. Starting from how one comes by ideas, develops them, manufactures them, keeping comfort a priority, and manages resources to come up with a great design solution.