when constrcting something 3D like a tent, each panel will have 3 to perhaps 6 edges. each edge will have a length, and worse, most lengths will have a curve. any change of either results in changes to the angls of intrsection with the other panels.
now.. every angle, and length, and curve, hides demons that will not be apparent until you build it and they appear. eventually you may learn enough to see most of them early on, but they just get better at hiding.
with "luck", and then a very large pile of prototypes, you occasionally find that you have worked yourself right around in a huge circle, are back near the beginning.
fabricators who have done this are considered "experienced".
along the way, everyody that formely liked you in the now distant past, will in no way, even under penalty of death, ask you about your "new design".
that's ok, they don't "get it", and even if they did, they univrsally lack the tenacity to proceed oorretly in making that last half a dozen beta units for the purpose of refinement. this is because during project developement, your friends turn into wussys. they were probably weakminded to start with, and a decent project simply brings in out in them.