I designed a rocking chair in Fusion 360. It can also flip up and became a small tabletop. I added small dog-bone structure for any straight inside corners and chamfer for easier fitting.
First cut with OSB went OK, except it didn't totally cut through and I have to use a knife to cut it off. Next time better to set a thicker cut depth. It fits OK but I was told the OSB is too frigile for me to sit on, so I didn't finish cutting all the bars, just put it together to see the shape.
So I decided to buy some better wook for this project. I figured I need two 4*4' plywood and went to Homedepot with Logan. I found the plywood I liked a lot and only costs about $40 for two board and everything went well until we find the board doesn't fit in the SUV we rented. And as it's getting late we couldn't find a way to bring it back on the day. We went back next day with a Uhaul to pick them up. The science center loading dock is very convenient for unloading the boards.
I added a another chair from opendesk in my design. I modified the design to make it slightly taller so I can use it as my piano chair. And because I bought 3/4" thick board the design for the rocking chair need to be changed too. Although Fusion 360 support parametric design, I found their 2D tool is very limited. So I redid the whole thing in AutoCAD which I just started learning and found really easy to use.