About this 3D model

My son came home from camp with this cool lanyard water bottle carrier http://www.scoutstuff.org/cub-scout-lanyard-water-bottle-carrier.html and I wanted to see if I could design something similar that was printable on my ToM. This is the result. There is plenty of room on this to add a logo or name on the top and it fits the bottles just as good as the scout version. Added crummy OpenScad. I thinkI need some real/better 3D design software.