Due to the size and scale of the former needed, i decided the best way to create an accurate former was to have nine identical layers cut from 18 mm hardwood ply, the files were created in autoCAD as a 2D dxf file. I wanted the shape to be quite geometrical, with filleted corners to create more smaller curves – which will hopefully smooth over when vacuum forming, these straighter surface will be easier to attach and cut foam to the surface for ease of upholstering in the future.
Due to the curved nature of the form, as i want the seat to almost ‘hug’ the person sitting in it, there are two noticeable undercuts in the form. In attempt to save these through the vacuum forming process i added a tolerance band across the bottom of the former face of 5 cm. This strip will allow for the retreat of the wood, if it moves due to the glue, or because the surface area will increase as each layer is added, and therefore three pieces the same size will not all extend to the same length.