Any way to edit before converting to segmentation node?

I loaded my STL file as model and I tried to convert it to segmentation nodes in a data module but slicer got freezed because the my STL file is too heavy.
So I want to cut unneccessary part away before converting it to segmentation nodes but don’t know how…
Is there any other way to make model editable without converting to segmentation nodes?

Thanks for help.

You should be able to use the Dynamic Modeler for this. It takes some practice but it’s very powerful.

https://slicer.readthedocs.io/en/latest/user_guide/modules/dynamicmodeler.html

You can also try to use the Uniform remeshing and Decimation tools in Surface Toolbox module to reduce the number of points in the mesh.

However, I’m not sure if the problem is really in the input mesh file. Even if the mesh contains millions of points, you may just need to wait a little longer to convert it to labelmap. It is more likely that you are trying to create a too high resolution labelmap out of your mesh and you run out of memory. If you open the STL file as segmentation (in “Add data” window select Description → Segmentation) then the labelmap resolution will be chosen automatically so that the conversion should be successful on an average computer.