Yes and no
writeobj will convert your entire map into an object file name of the first argument (aka /writeobj hello) would create a 3d object model call hello which will be located in /%SAUER_START_DIR/packages/models/%NAME_OF_MODEL/%NAME_OF_MODEL.obj. Along with the diffused textures of said model. Some times (normally on larger more more intense meshes, this file can corrupt. So exporting an entire map may or may not work, depending on how many world tris there are and how advanced your processor is (I found that the slower processors mess up easier then the faster processors.
All in all it is possible to convert a map into an object file (ive done if for a variety of projects) tho its not always reliable so its best to try it multiple times, or just export smaller texture files. Also a side not, it somethings flips the normals incorrectly, (not sure what causes this, it should be easily fixed in a model editor :)