Tight bounding box of surface with C#

I am trying to get tight bounding boxes of surfaces with C#. my geometry exists in Rhino, so I should be able to use the RhUtil.RhinoGetTightBoundingBox suggested by this post. However, I don’t know how to import RhUtil. using RMA.Rhino.RhUtil; doesn’t seem to work (maybe cuz its too old?)
Is there a way to access RhUtil now? or is there some smart workaround (like getting the bounding box of edges or something) to get tight bounding boxes?

this post suggests something for C++ but I don’t know if the library is available for C#.

Thank you.

NVM i figured it out:

first convert to mesh and then get bounding box will give a tight bounding box:
face.GetMesh(new MeshType()).GetBoundingBox(true);