Change shape when export to stl

Hello everybody,
I have a problem when I export a drawing in STL format.
The problem is: I have a plan that I have to export to STL to print it using the 3D printer.
Stl format, changes the shape of the solid that I drew, in some parts, you have any suggestions?
thank you all

I’m afraid you’ll need to post the original file along with the settings you used to export the STL in order for someone to see what is happening… NO way to know what is happening otherwise; “changing the shape” is rather ambiguous.

An stl file is a faceted approximation of a smooth object, depending on the settings, lots can actually “change” significantly from the original to the stl.


Thanks, I solved was a problem setting