"I would like to be able to make solid models of cutters and holders and be able to import them into the libraries. "
You can already do this. When you create a tool there is on option on the tool dialog to Export tool to Library.
As for Exporting the solid of the tool and Holder they are simply .prt files that are in the UGII_CAM_LIBRARY_TOOL_GRAPHICS_PATH folder.
Look in the help docs on Customizing NX Library.
When you edit a tool the system creates a solid body of the tool and holder. You can then select Window - More and the tool should be on the list of open files. Select the tool and now you have a solid model of the tool.
If you want to see some examples retrieve the tool ugti0202_019
When your in the tool path Verification set the tool display to assembly.
If you are looking for some automated approach then you will need some UG Open code to do this.
John Joyce
Tata Technologies
1675 Larimer St.
Denver, CO
NX3,4,5,6 Solid Works, Pro/e, Solid Edge