I am a very very beginner to Tinkercad and can't do much! I am trying to modify an item from Thingiverse. It is a stand and has two posts onto which another object is mounted.
The object is here: http://www.thingiverse.com/thing:3611725
I am trying to increase the height of the posts to 60mm. All goes well, I then export back. But when I print it out the extra section seems to get printed with less infill or something, because it just breaks off easily and I'm back where I started!