I used Modelling clay to make my 1.5 scale model. To keep the structure of the model I used wire inserts which doubled as the back support springs. I needed a clear padding for the back and padding for the seat. I cut up some bubble wrap and removed the cardboard for the clear back padding. The clay was hard to mould and didn't stay in it's shape well.

For my rendering, I copied my model. This helped as I was able to get a good angle for me perspective as well as a real view of how the chair will actually look. One thing that made the drawing hard was the inconsistency of my clay model. As the edges were not square, my drawing was not square.

This is the side view of my re-designed chair, done on Solidworks.