You forgot to add the property [font=courier new]multiPartModel#[/font] set to [font=courier new]true[/font] in [font=courier new]PluginFurnitureCatalog.properties[/font]. By default, this property is [font=courier new]false[/font], meaning that all the files depending on the main 3D model file won't be saved (here, MTL files won't be saved, and only the OBJ file will be saved at root of the SH3D file).