3d printing closed brep

I am preparing a definition for 3d printing. From my previous experience with other 3d applications, I know hat creating a proper printable .STL file is not always an easy process.
I wondering if my end result in my Grasshopper definition is a CLOSED BREP is a kind of guarantee that I can 3d print the file?
Is there any utility for Grasshopper which I can check my result is printable?

It’s more about the STL mesh that you export as this is what is normally required to be a closed, valid mesh.

Try the free version of Netfabb to analyse your STL file.

If the STL file is no good then start looking at the Brep to see if it is self intersecting etc.

As @martynjhogg said, if you export your brep to a stl file it get’s meshed and could have some errors.
netfabb and makeprintable.com can check this and repair. For me this always worked.

If I want to be sure that during the export it is not f…ed up, Should I convert the BREP to MESH within Grasshopper?

Rhino is pretty good at creating STL meshes… Just save as STL

After 3D printing many GH/Rhino parts I’ve learned that it is essentially impossible to tell ahead of time whether or not it’s better to bake from Breps or meshes. I try Breps first and if the results aren’t so good I try converting to meshes. But either way it is frequently necessary to use the new Netfabb repair service at https://service.netfabb.com/login.php to get a valid STL file.

I’ve also found that the most reliable slicing program is the Prusa version of Slic3r: https://github.com/prusa3d/Slic3r/releases

What is a slicer program good for?

A slicer creates the code to run the 3D-printer. If you’re outsourcing the 3D-printing you don’t need to use this.