What happens when students choose their projects?

While I was working with my Level 2 boys today, the chat got round to project / topic choice.
I was asked "can we design shoes?"
So my reply to the Level 2 (Year 12 ) boys was "do you want to design shoes instead of shelters in Year 13?" They already know the Level 3 main project is a portable shelter as they see it in the lesson (my class is a mixed level class)

Their reaction was quite excited, which then got even more so when I told them of the 3D printed shoes that I had seen online recently. I have put this idea past my other class of Year 12 students and they seem keen too. So it looks like I am rewriting the Level 3 Product Design project, which is all good. I would rather they did something they were keen on as this is a big project and takes up a fair chunk of time on the course. It is also god advertising for me, getting them interested for Level 3 while they are still in Year 12!!
I sent student R these links today as he was the one that started all this. Hope it will blow his mind as he was "really??...we can 3D print shoes???" today.

Link 1
Link 2
Link 3

So their job now is to work out what materials we need to 3D print something flexible and if it needs a different printer. We need to know that before the budgets are due in at the end of the year.