Create an icon/Shortcut in main menu

Spaces are not recognized in Ubuntu file paths.

You should either rename the directory so there is not a space, or you can use \ to denote the space in the file path. It should also work to use quotations.

Examples

Exec=/home/pedro/Programas\ Baixados/SweetHome3D-6.5.2/SweetHome3D

Or

Exec="/home/pedro/Programas Baixados/SweetHome3D-6.5.2/SweetHome3D"