From stl file to a rhino.rdm file

Hi to everyone, I have received an stl file which I would like to modify.
When I try to boleansplit or boleandifference it does not work. How can I do? thank you,
Mirco

ps. file attached
CLASP001 SPRING HINGH LOCK-BG.stl (816.4 KB)

Stl files are meshes, are you using mesh booleans? did you checked if it’s an open mesh, normals, etc.?

it works for me, no problem

Hi Nachetz, the matter is when I click on the polysurface this does not light up. How can I check if it is an open mesh? did you cut it without doing anything. The command I used is bolenasplit. or tried to used boleandifference. Where is it mesh boleans? Thank you

Hello - stl files carry only meshes, not surfaces or polysurfaces. MeshBoolean* commands are in the Mesh menu.

http://docs.mcneel.com/rhino/5/usersguide/en-us/html/ch-02_rhinoobjects.htm#:~:text=The%20fundamental%20geometric%20objects%20in,objects%2C%20and%20polygon%20mesh%20objects

-Pascal

Thank youoooooooo!!! Mirco