The basic framework for this folding chair is done and there is a back to lean against. It would help to have something to actually sit on. This should be pretty easy. Right. It really should be easy and were it a simple board or something it might be. It doesn’t, it has a little more sculpt to it than that and it’s metal.
The first really issue was deciding how to create the seat. It’s roughly square or rectangular shaped so a cube seemed like the best starting point. So I tried that first. Now it is a folding chair and I want it to be able to be folded up so I do need to properly finish out the bottom side. So with the cube shape I started by adding some edge loops and then I did some extruding to create some crisp and close edges and in the process I was able to recess those faces into the bottom. It got it all set and then added more edge loops and tried the 
turbosmooth modifier. I got some of the roundness in the corners that I needed but trying to get that slightly contoured look to the seat where you sit didn’t look like it was going to work very well.
Looking at it I started to wonder if perhaps using a cylinder, even with all the work to flatten the sides, might be a better idea. So I created a cylinder, flattened the sides using the soft select tool so that I would impact the selected edge more than the rest and I was able to do most of the transformation that way and then only needed a small amount of individual edge manipulation. But if you look you can see how the difference in the way the edges and points are arranged makes a difference. The first is the seat from the
cube and the second is the seat from the cylinder.
Just because I thought the cylinder would give me better surface flow and edge flow doesn’t mean I didn’t still have a lot of work to do. As you can see I had pretty sharp corners at this point and they were going to need to be rounded out so I added edge loops to give me more geometry to work with. I didn’t quite expect, when I did the first one that it was going to basically loop around the corner but that’s what it did. It was a nice thing because that kept the center from getting too crowded.
I did quite a lot of manual manipulation of the points to get a nice round corner. The first one I did looked good so I started working on the next, and so on. I got them all done and realized that they weren’t quite round enough. They needed a deeper curve to them. So I started over with the point manipulation and did them all again. It took a good amount of time. The underside had to be moved too and I didn’t want the surfaces breaking through each other. Yes, at this point I was thinking that I really would have been better to get the main shape and then add the detail to the underside. Next time.
After the corners were rounded off I added a little contour to the seat surface. After all that was the reason for starting over with the cylinder. And now it’s really coming along. Next up, details.