I was going to experiment with putting a foam core wall around my 3d printer to see if it would cut out some of the noise in the other room. I initially made this just a simple part, but carried it further & made it parametric with quite a few variables. You can make 90 degree corners with 2 or 3 connections. You can vary most of the individual dimensions of this part. You can create either 90, 120, 72, 60, 45, 40, 36 & 30 degree corners. This allows you to connect foam core or some other sturdy flat material & make 3 sided, 4 sided, 5 sided, 6 sided, 8 side, 9 sided, 10 sided or 12 sided structures. I am only using it for 4 sided with what I needed, but added the others while it was fresh in my mind. You might have to fine tune your printing for the 3 corner version as it prints at a 45 degree to eliminate having to add support. My print of that version came out a little rough, but quite usable. I added 6mm brim for that print.

To use this with another material besides foam core, change the Gap variable for the width of your material & add a little extra width for clearance if you need it. I used 4.5mm to use with the foam core I have. All the customizable variables are documented as to their purpose. You can also open this in the Customizer.