I am going to creat a plane by 3 fiducials，and then cut a model like the module “modelclip”?
You can copy-paste a few lines of Python code to the console to orient a slice plane using 3 fiducials: https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Fit_slice_plane_to_markup_fiducials
Alternatively, if you don’t want to use the Python console and you need to cut a closed surface, then you can use Segment editor module:
- Segmentations module (Import/export section): import your model into a Segmentation node
- Segment editor module: cut the segment using Scissors tool in either 3D or slice views
- Segmentations module (Import/export section): export segment to model