I have been asked to produce a liner for a garden fire pit.
Basically my customer wanted it as a dished construction approximately 2600 diameter x 400 deep in 6 mm thick mild steel, he would then dig a hole in his garden to accommodate it. I explained to him that we would not to be able to make it as part of a sphere and he agreed to have it as an octagon which we could manufacture by cutting out segments on our CNC plasma, rolling them on the centre line and then welding together as per my attached image.
However, I can't work out how to model it and was wondering if someone could point me in the right direction?
None of the sizes are important as he will simply dig his hole to suite my fabricated liner.