I made this lung model as a gift for a friend doctor. There are slight anatomical differences among the same human organs: I have chosen to print this particular scan because the front parts of the lungs slightly overlap, giving the structure more strenght. Otherwise, the only trachea should keep jointed the two lungs, and the structure would be more fragile. Please notice that the .stl file is as big as 48Mb. this because it is a high resolution. It's a long print: it took me about eight-nine hours. If you have a 3D printer similar to mine (RepRap Pro Mendel) you may consider to print the modellopolmoni.gco file, wich is the same I used. Here you find a video I made to show the making of my print. https://youtu.be/2C1jSBreGUUYou totally have to print this model with raft and support. You may want to use my modellopolmoni.gco, or make yours according to your printer. Also, I would suggest to avoid low infill, because the middle part of the model will be full of support material, and if your printed piece is fragile, you could break it while taking away the material. I suggest to use two different pliers: one robust medium plier to tear off the strongest parts, one little plier to go inside little spaces and finish the work.