Problems with cura leaving out parts of my model

[JOMS 1]

This is the model i am trying to print but after slicing it in cura it seems to leave out some of the steps on the outside of the cylinder.

 

 

It also seems to have made some strange gaps between the upper steps.

 

 

 

There is also another model that i have made that goes on top of that one with which i had the same problem, but managed to fix it.

 

 

As for the bottom piece that remains broken, I don't know how to fix the problems with the missing steps.

[gr5 2,234]

So that looks like sketchup.  And I can see that some of the faces are white and some gray.  So the first thing to fix is, in sketchup, all gray suraces - right click on them and select "reverse faces" such that the surfaces are then white.

 

Also make sure there aren't any interior walls that don't need to be inside your model.  Those also mess up cura.  Try that and if you still have trouble, post your STL file for us to look over.

[gr5 2,234]

Maybe I should explain better - STL files have a set of unordered triangles and each triangle has an "in" side and an "out" side.  The side facing air is white and the side facing interior is gray in sketchup.  If you get those backwards, Cura gets very confused and sometimes does not print certain features.

[JOMS 1]

Thank you, it seems that the cylinder did extend down through the whole model and as soon as I changed that so that it stopped when it got to the top of each step it managed to fix it.

 

(I do apologize i should have specified what modeling software i was using but the solution that i was given worked anyways)...(I was using Rhino 6)  

As seen by the dotted red line, i used the edges of the steps to trim the cylinder.

 

Thank you for the help, I was stuck with this for a while, I just wanted to post the process of my solution if any other  people have the same problem.