How to elicit a ray and tangent to the ROI region (use a python script if possible)

Development
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Operating system:windows 64 bit
Slicer version:5.7.0
Expected behavior:
Actual behavior:

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Could you please provide a bit more details and perhaps a picture illustrating what you would like to achieve?

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3d slicer
3d slicer846×502 15.2 KB

Maybe like this,but please note that the point might not be on the same plane as this graph，and the graph may even be a 3D graph.How can I achieve it?