I've constructed and flown a couple of 3-D printed rockets from Boyce Aerospace Hobbies.
https://boyceaerospacehobbies.com
Certainly 3-D printed parts and complete kits are going to be part of the future for this hobby. Specialized applications for a very limited quantity market are where 3-D printing really shines.
There is a learning curve for anyone interested in building and flying these types of rockets. Sanding and finishing these rockets is more involved than for most airframes. Wet sanding is a must if you want a nice looking finish.
These rockets also react differently to the forces involved as well. Recently, I suffered a shock cord failure when the kevlar shock cord came loose from its attachment point on the rocket. The shock cord was glued with CA between two parts of the airframe.
The failure was not in the design, but all mine. I used kevlar cord that was too thick, and probably not long enough. (3-5 times the length of the body tube is a must with these rockets.)
Attempting a field repair, I opted to drill a small hole in the airframe and attach new kevlar through this hole. That resulted in a "horizontal zipper" on the next flight. Which made total sense when you think about how 3-D printing works. The "layers" of the rocket separated under the force of ejection.
Lesson learned for future builds.
Also, these rockets are heavy. Keep that in mind when running your simulations and selecting motors.
I'm in the process of building a new rocket that will test 3-D printed fin cans on a carbon fiber frame at mach+ speeds. We'll see how the material reacts to those stresses.
Learning stuff and having fun. Thanks for sharing this build thread. Can't wait to see how it flies.