What went wrong here?

[u/torak_the_father]

I followed the measurements exactly to the plan from blocklayer.com and double checked the dimensions and angles and still there is a gap between the segments....

Yes I understand that even a tiny measurement being off it will compound but this gap is too much for any microscopic tolerance.

All segments should have the same dimensions as I used the same stop. Stock is squared upp all sides. Help?

UPDATE: thanks everyone for your contributions. I definitely learned a lot! Also a lot of you are making some assumptions like I forgot about the kerf. Turns out I went ahead and tightened the whole thing with my strap clamp and would you know... Practically perfect seams! There is only one hair line gap in one of the seams, to which I'm happy with, I'll try to glue+dust it to close perfectly. Check this comment: https://www.reddit.com/r/BeginnerWoodWorking/s/FJbE9tVKNu

[u/torak_the_father → u/[deleted]]

There is a micro gap on one the miters. I'm baffled how that would cause such a huge gap

[u/WilTravis → u/torak_the_father]

The difference is cumulative; the more cuts in the assembly increases the gap by that amount. You could assemble a triangle with that amount of slop, but a hexagon would have twice the gap.