Converting a 3D surface (stl mesh) into a 3D SketchUp object

[mbernard]

Good morning all,
I have an STL file that represents a 3D surface (without thickness). It is a mesh based on triangles (Over 600,000).
This surface should have a flat base of a certain thickness with opaque faces on the sides in order to present the appearance of a solid object without hole.
I want to be able to use this surface in SketchUp 2019 software to apply a wood texture.
Please tell me the different operations to be performed to achieve this result.
Regards,
Marc
See file in attach.

[pilou]

Plugin Import Export STL by Didier Bur!

[nlipovac]

I use Ultimate Unwrap 3D to open them and export them to SU. I use it for UV unwrapping and this part is a plus for me, also you could use Blender to open ti and export it to obj.