Divided objects with dotted lines

[Guest]

Whenever I divide an object (two objects overlapping and I want a part to go behind and one part in front) I generally colour in the divided shapes to suit. However when I save the file as a pdf, a small line appears around the divided areas I have coloured in. Is there a way to fix that or is there a way to do the same process but a lot easier. I'm still quite new to illustrator

[cmgap]

Once you have divided the object why not delete the lines? Select them with you direct selection tool and delete.

Also in Acrobat you can check 'smooth lines' in Preferences > Page Display to see if this helps.

[Guest]

I cannot delete the lines, using the direct selection tool only deletes the shape