I have made the model, but stuck with the joinery part as shown in the image.
can some one one help me to understand how can I get the joinery as shown in the image below. I want joinery to be alternate and equally divided to achieve a neat model.
Thanks in Advance.
Please Download the file we transfer link below the size of the file is 40Mb.
https://we.tl/t-yX0IoaumOu
in the attached file the surfaces have some self-intersecting problems, and there are several duplicate/residual bits of curves here and there, could you upload the original mesh file you used to get those sections? probably the mesh needs some cleanup before being sliced
once you have very good outline curves, I think I would go left-to-right (then right-to-left) and project along X / -X the outline of the next section onto them
this will identify areas on the first section where -if you put a join there- you could actually find some material in the next section, and would allow you to place perfect perpendicular joinery
random example: project red into blue along X
[I have raised their distance just for visualization purposes]
any point(s) picked on the green curve (using whatever spacing/distribution method you might want to use) will allow the join to perfectly lie on the edge border of the red surface and be perpendicular to it
if the joinery does not need to be perpendicular, then the situation becomes much easier 
you might just use surface closest point to the next section
just one thing, if you are planning to lasercut this, I have worked on similar structures -but made out of thin lasercut wood-
remember you lasercut -and mark- only from one side, but you will have to make connections on both sides
I would advice to have small join-marks to be present on both sides by having small things (like tiny circles/lines) cut through the material… it’s always better than playing the guessing game on the opposite side in front of a mirror (or, in my case, to just manually drill a hole on each single mark of each single section 
)
