The X3D writer produces a single .x3d file for each FME feature type that it sends to the writer.
The VRML writer produces a single .x3dv or .wrl file for each feature type that it sends to the writer. In the Virtual Reality Modeling Language (VRML) Writer Parameters dialog, you can choose the VRML version to write out.
In Workbench, the X3D/VRML Writers support feature type fanout and will write a different X3D model file for each feature type. Old files in the output folder are overwritten by the new files with the same name. If the output files cannot be written, the translation fails.