Here is a fantasy bottle I designed by digitally sculpting a form by hand, if you will. I used 3dCoat, so the process is very organic. The point of this excercise was to depart from a mathematical look, and see how organic a form could be executed. I like it :)
You have the right the print this out for your own personal use as per the Attribution-NonCommercial-NoDerivatives license indicated below.
1. You may also rescale the item in any direction to fit your needs.
2. You may use photographs of your printed items in any way, including commercially. For example, if you are selling pretty roses and you want to display them in a bottle, this is permitted. For example, if you are advertising a 3d printer you have for sale, it is permitted to show a picture the bottle as an example print. As a courtesy, I ask that you provide a credit to me as the designer of the bottle if possible. However, credit is not a requirement that will be enforced.
You will need some kind of support structure to print this nicely. The bottom ridges, in particular, have a hard time. WIth the pp3dp printer, I used it's default (50 degree) support settings.
Also, to hand paint the item, I used sharpies of all things! You can layer sharpie colours and they will blend nicely with the scrubby/brushy techniques, as the solvent in the ink dissolves into the under layers of ink. I think I was told that the solvent in the ink is related to acetone, and that may be what enhances the glossiness of the print when painted with sharpies.
Oh, one more thing, which I have not yet tried. In another "thing" someone had mentioned that they use a polyurethane coating on the inside of vases to seal them and make them watertight. They suggested that the cavity be filled with polyurethan, then emptied, and left to continue to drain/dry upside down. I will let you know how this works out.