@unknownuser said: I WANT IT 2D TO 3D What version of SketchUp are you really using? Your profile indicates a version that does not exist. If you would share the correct information with us we would know what tools you have available to you and we could guide you properly.

Make sure the face orientation is correct. Blue back face toward the inside of the volume. Then soften the edges by clicking on them with the Eraser tool while holding Ctrl.

Plugin Import Export STL by Didier Bur!

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.