his A2toA3 tool
which can assist in moving Arma 2 content (including Arma 2: Operation Arrowhead, Arma 2: British Armed Forces and Arma 2: Private Military Company) to Arma 3.
Quote SgtHunter :
The idea for this application is based on DarkWanderer's Porting Script. I simply thought I could create something with an interface that is more user friendly.
This does not modify or include the original files of ArmA 2. Please keep in mind that some things don't work in ArmA 3. You can select what maps you want to port, what types of files (Weapons/Vehicles/Characters/Sounds) and what games/DLC you want to include. It's based on creating hardlinks to the files instead of copying them, which saves you space and time.