I have spent a lot of time putting together a tree inventory for a large park and saved it as an .sdf file. (I'm new to map3d and I exported the file to sdf, but forgot to close the data for editing and then lost the data in original form when I reopened it, so I couldnt save the shp). Then I realized I need it to be in a shapefile format to open in arcmap. Is there way to convert an .sdf file to .shp file or a way for it to read in arcmap? What is the point of .sdf files if they are only readable in map3d, but the program can also make .shp files? Please help, I dont want to have to start over completely because of this.Thanks

You can use the MAPEXPORT command to write SHP files.

Import the SDF file into a blank file, then turn around and export to SHP, provided it's only one object type in the SDF file.