Initially, I attempted to make a bentwood chair using door skins and a mold. However, I think the radius of the curve was too small and even after wetting the wood and steaming it with a tea kettle, it broke.
For my 1:1 model, I decided to make it out of chipboard. First I measured and drew out the side views of the chair with a ruler and compass. Then I cut them out. Next I cut out the sections I would use for the top view. To get them to bend, I kerfed them and kept them in the desired shape with wood glue pressed against a box to dry.
As seen in the pictures, the flexibility capability is very promising. These are two images over one another with one of their transparency set lower than the other. The picture with darker backrest is the initial resting form/position where as the faded/ghost like image is the flexed/pressure exerted picture.
I started by assassinating mechanical pens for their springs. I then wrapped fabric around the springs while they were. This was so when the backrest is exerted with weight the fabric curves and adjusts to the body but when not in use the fabric snaps back into a linear straight form.