Hi, I have this Cylinder and Cube. Cylinder is parented to the Cube and duplicated as you can see in the right down corner (option "verts"). Now I don't know how to convert the duplicated Cylinders to meshes, so I could have one mesh. Now when I switch to edit mode I still have only one Cylinder and the duplicated eight are not real meshes but only duplications. Do you know how to fix it? Sry for my english ... .
You can use the "Make Duplicates Real" function Ctrl+Shift+A. This will generate one object for each duplicate, but the generated objets will still share the same mesh. You can join them Ctrl+J to make a single mesh with all the cylinders. You can then separate each to an object with its own mesh by going to edit mode and P "By loose parts".