So I have recently tried to replicate the whole "3D printing in vase mode concept". Basically, you make your cad model so that the nozzle of the 3D printer can print it without lifting the nozzle even a single time. I tried to replicate this in the part that I have shared below by first importing my target geometry and then making ribs. These ribs must be 0.1mm thick as per many YouTube tutorials. I have done this by setting the thickness parameter to 0.05mm in the thicken feature and selected the symmetric thicken option. This means the thickness comes out to be 0.1mm. If you would like to change this parameter, no need to go inside each thicken feature, just change the Ribs thickness variable in equations. Remember if you type in a value of say 0.05mm, the ribs will be twice that thickness. 
I have also extended each rib surface (surfaces were converted to solid using thicken feature) slightly using the extend surface command and then cut the resulting bodies on front and back using planar surfaces to avoid the zero thickness geometry error. Then I cut the ribs to the shape of the target body using surface copied from it outer surface. Then I thicken cut the ribs to separate them from the outer surface of the target body by 0.4mm. This dimension also comes from online recommendation. Finally, the last step is to subtract these ribs from the main body. This is where I get problems. The combine tool completes without error but it randomly deselects one of the ribs and also the other ribs are subtracted but they don't leave a hole on the body as you would expect from a subtract Boolean. This issue is shown in th attached video.
Finally, i want to say that I tried other tools too. Intersect command fails. Indent command works on all the ribs and produces the desired result but for some reason it does not work on the center most rib (the one in the middle). Indent command works on all ribs if there thickness is 0.2mm (rib thickness variable set to 0.1mm). 
PLEASE HELP!!!!!!!!