Currently the fbx importer is within the editor so it isn’t compiled for games. Additionally the processing steps for optimizing the mesh and creating collision and physics data are in the editor as well. These are somewhat expensive tasks to perform at runtime and creates a lot of editor only data so we haven’t made it available to games. With source code access you can of course change this yourself if you want to. We’re in the process of converting the fbx importer into a plugin which should make it easier to get the raw mesh out of fbx and create a static or skeletal mesh from it at runtime if you’d like.