I usually get this error when the data is not plotted down to the skeletal rig and the control rig is still turned on. It’s not importing anything because there is nothing to import more or less.The problem I see with the tutorial is it’s all being done as one big chunk (OBFF don’t ask;) ).
The better work flow for me is to import the Daz model into UE4 (and there will be issues) and into Motion Builder to establish a match set of skeletons.
Next I create a source folder for the exported animations from Motion Builder that I can import per take into UE4. (if under UE4 it gets updated for you with out having to re-import)
Once that’s done I then do my thing as to whats needed (per take) and plot everything down to the skeletal rig (very important) and check to make sure that the Character Control > Character > Source is set to none.
This where where I think things generally goes off the rails. In the tutorial you will be saving everything in Motion Builder “native” format and it’s up to the target app to extract the information from the wrapper and that’s a lot of structure data.
The better work flow since you already have a matched set of skeletal rigs in MB and UE4 is to export just the animation takes.
With source set to none go Character Controls > File > Save Character Animation
You will be presented with a save option and I usually set to Save One Take Per File (the take name is used as the name of the exported FBX file)
Next step is the option screen that you can tell MB what to export.
In this case you don’t need to Save Control Rig but might want to Save Character Extension and more so if using the Epics blue man or using AUX helpers.
Select the takes you want and hit the go button.
Since the Daz rig is already in UE4 ready to accept animation you can then just grab all of your saved takes, drag them in as an import and tell the dialogue to target the Daz rig and and just sit back and watch the fun.
Now here is the big reason why you would want to use this work flow instead of OBFF. It can take up to five minuets, or even more, just to update a single clip but as a take it will update faster than you can switch between MB and UE4.