Mesh split problem

Rhino Rhino for Windows
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1

I am having trouble with splitting the attached mesh with a surface. Most of the mesh split, but there are remnants that did not. Thank you in advance for your help!
tree bark only.3dm (5.2 MB)

2

if you want to split a mesh, use a mesh as cutting object. convert the surfaces to meshes with a dense polygon count setting to improve the intersecting calculations.

image
image1279×718 407 KB