Hi , I am new user of Rhino and Grasshopper , I am trying to extrude black region of qr code , i achieve it thanks to Laurent Delrieu’s work but for example when i want to save it as an STL file there is an error like there is no object in your work. How can i define my extrusion as an object. Thanks for your replies 
here is my work;
Did you backed the geometry before exporting?
thanks for your reply , Since i am new , i do not know how to use these programs exactly , how can i do that? ( Sorry for simple questions 
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right click on your extrusion output and “bake” to rhino document. as long as you didn’t do it, its just a preview in rhino not an actual object.
You need to right-click the ‘Extrusion’ button then ‘Bake’ it to make it available in Rhino viewport
thank u so much
