OpenArena Map Portability

Using Q3 maps in OpenArena
OpenArena is generally compatible with Q3 custom levels, just drop the PK3 into the /baseoa/ folder. However, if the level uses stock textures from the Quake 3 base game, you may experience some missing textures. One of the simplest way to resolve this is to add a Q3 high-res texture replacement pack into the /baseoa/ folder, such as the XCSV Hi-Res Texture Pack (xcsv_bq3hi-res.pk3).

Using OpenArena maps in Q3
Most OpenArena levels should work in Q3, just drop the PK3 file into /baseq3. Missing textures can be solved by extracting the 'baseoa/pak4-texture.pk3' file from OpenArena and dropping it into /baseq3. You may need some of the other pak files from the baseoa install to fix other aspects of the stock OpenArena levels (shaders, bot AAS files).