Hi Bryan. What kind of 3D printer do you have? What CT machine so you have?
You can join RSNA 3D printing Special interest group, there is a lot of info there and a very active community from a lot of different hospitals and institutions.
You have plenty of tutorials at embodi3d.com, mainly focused on using open source software for segmentation and 3d modeling. There are some topics on 3d printers, too.
I personally used MIMICS it is a more straightforward and easy-to-use tool for the segmentation and generation of 3D models from CT and MRI. Check with the trail version from MIMCS.
3D slicer appears to be a good open-source alternative https://www.slicer.org/ for an initial try.