PTC Creo has very powerful analysis tools and optimisation/feasibility studies. Put these two together and it's possible to modify 3D models to achieve a desired goal, This family of water bottles was created using these techniques.
The bottles shown here are 1 litre, 500ml and 330ml with the same neck so that the same cap can be used on all sizes. The attached zip has these Creo models and "How-to" instructions.
Note: the models were created using Creo 2.0 Academic Edition. The instructions should enable those not able to open the models to create their own.
