Is there something to rescue from an Oracle Data Modeler design just with the 'logical' folder? First of all, I even don't know how naive is the question, we start studying this not long ago.

A friend of mine was working on Data Modeler, he saved the design and he only got the "logical" folder, without the other ones nor the .dmd file, is still possible to open this with Data Modeler and rescue something or all the work was lost?
It could be possible to rescue the ERD - if the files in the "logical" folder are intact.

Perform the following steps:

Load the datamodeler, create a new model (name here: new_model), leave it empty, save it.

{1} Operating system/file manager: Give the new_model's "logical" folder a new name.
(Avoid name clashes with the rescued "logical" folder.)  

{2} Operating system/file manager: Copy the rescued logical folder into the new_model's folder.

{3} datamodeler: Close the new_model.

{4} datamodeler: Re-open the new_model.  Right-click Logical Model, click Show.

Example session (Linux)

# Directory listing _after_ the (empty) new_model has been created and saved.

[oracle@vbgeneric Documents]$ ls
new_model  new_model.dmd  erd_one_to_many erd_one_to_many.dmd

[oracle@vbgeneric Documents]$ cd new_model

[oracle@vbgeneric new_model]$ ls
businessinfo          datatypes        dl_settings.xml.merge_conflicts.local  mapping  rdbms
ChangeRequests.local  dl_settings.xml  logical                                pm

[oracle@vbgeneric new_model]$ mv logical renamed_logical

[oracle@vbgeneric new_model]$ ls
businessinfo          datatypes        dl_settings.xml.merge_conflicts.local  pm     renamed_logical
ChangeRequests.local  dl_settings.xml  mapping                                rdbms

[oracle@vbgeneric new_model]$ cd ../erd_one_to_many/

[oracle@vbgeneric erd_one_to_many]$ cp -R logical ../new_model

[oracle@vbgeneric erd_one_to_many]$ cd ../new_model

[oracle@vbgeneric new_model]$ ls
businessinfo          datatypes        dl_settings.xml.merge_conflicts.local  mapping  rdbms
ChangeRequests.local  dl_settings.xml  logical                                pm       renamed_logical

# Close the new_model.
# Re-open the new_model. Show Logical