I think the gathering must be prepared first, This example looks like a normal embroidery design worked on the gathered fabric to me. Looks nice!

smoking designs from Elizabeths require a pleater.. but I do have some from Dainty stitches that dont but i have not yet tried these lol..
a project for another day maybe, photo below of dainty's design ds0996
big hugs - maria xx

Try it on a scrape ,i love it and would love to see how it works .let us know when u can ok hugs Carolyn

I haven't tried it but I've heard a lot about it. Elizabeth's site is the one to go to for the best smocking designs on pleated fabric and done ITH. She has a lot of information. Others are more faux still so I guess its what you want but most are happy with Elizabeths work.

The pleating is done first on a pleater, which can run rows of straight stitch about 1/4 inch apart. They come in 16 and 32 row. Of course you can do that part on a sewing machine but to have them all perfectly stitched would be a real test. The embroidery can be done in a hoop but the finished look is not the same as if done by hand. Not saying that some designs are quite lovely done this way. If this design is done by hand only the top fold of the pleat is caught in the embroidery stitch. When done on the machine all the folds would be flatened.

For true smocking it should be pleated but an alternative is to put elestic thread in you machine bobbin, stitch several rows about 1/2" apart stretching it out as you go. It will gather/pucker to look sort of like the pleats and you can then do the designs on top. I did this years ago using just the decorative stitches on my machine and it was fun.

Try the machine embroidery on a piece of pleated material, then make it into a craft object [ like a coat-hanger or pincushion]. Then it will not matter that it does not stretch as it should for the bodice of a dress.