Anyone interested in segmentation should have a look at openanatomy.org for freely available 3D models and a cool web viewer: https://www.openanatomy.org//
Most of the atlas data was created in Slicer, and of course people with segmentation-related skills are encouraged to consider contributing to the project.
Also note that on the website there’s a link to a page where you can vote for the openanatomy.org for possible funding, so please vote if you like the project.