I am currently working on a helmet for 3D print, and have fully completed the design up until hollowing out the part. Currently, it is filled, but I would like to shell it to a thickness of 0.13 inches. Unfortunately, the shell tool will not work because some of the surfaces have a very small minimum radius of curvature. The only alternative which I can think of is to manually make cuts into the part to hollow it out. While this is possible, it would be difficult to make a smooth interior, which is the ideal in the finished product. Also, it would be nearly impossible to make a consistent thickness for the helmet.
Are there any other ways to bypass the minimum radius of curvature and fairly easily shell out the helmet?
If not, what would be the most efficient method to manually shell it?
Thank you for your assistance.