This answer applies to EA.
You can import individual files or whole directories, recursively or no. Directory import is by far the most common case; single file import does not allow you to create a diagram automatically.
When you import a source directory, you have the option of creating diagrams for each UML package, or no diagrams at all. You also decide whether to create packages for each source code directory, namespace (default) or file.
If your code constists of only 20 classes then it's likely they're in a single directory and/or namespace, so play around with that option (Package Structure in the Import Source dialog) to get the right number of diagrams.
In the same dialog, there's a button "New Diagram Options," which opens another config dialog where you can choose whether the diagrams should contain the classes' attributes and/or operations. You can also make the decision on a visibility basis, eg show public members only.
This dialog only affects what's shown in the diagrams when they are created. The members are still imported, just not displayed. This sounds like what you're after.
You can change the display options for any diagram by double-clicking an empty area of it, or right-clicking and selecting Properties. It sounds like you got into this dialog and changed something around, but I can't really tell what. The situation you describe, where you can't get the display back the way it was, is not one I've ever encountered in EA.
It is also possible to select display options on a per-class basis by right-clicking it in the diagram and selecting Feature Visibility. I don't recommend you use this in reverse-engineered diagrams, I'm just mentioning it for completeness.
The layout you describe, with all classes in a meaningless diagonal, suggests to me that the diagram isn't being laid out properly after creation. The diagram creation is a two-step process; first all the classes are dropped onto it, then the layout is applied.
This is strange, as EA automatically lays out generated diagrams and I haven't been able to find an option which allows you to deselect this behaviour. If this persists, send a bug report to Sparx Systems. You can always lay out the diagram by opening it and selecting Layout Diagram from the top-level Diagram menu.
If, finally, your classes are spread out among different packages and namespaces so that EA generates multiple diagrams for them, you'll have to merge them manually. Do this by opening both diagrams, selecting all (Ctrl-A) in one, copying (Ctrl-C) and pasting (Ctrl-V) into the other, then ask EA to Layout Diagram again.
So:
- Right-click an empty package in the project browser, select Code Engineering - Import Source Directory.
- In the dialog, select the root directory and source type.
- Tick "Create Logical Diagram for Each Package" and select the Package Structure which best fits your source structure.
- Click "New Diagram Options" and in the new dialog untick "Show Attributes," "Show Operations" and "Show Property Methods" if applicable.
- OK both dialogs.
- If multiple diagrams have been created, copy all classes into a single diagram.
- If the layout looks bad, select Diagram - Layout Diagram.
Hope this helps.
Best Answer
For Version 8 of EA Corporate Edition. Open or create a project. Create empty class diagram. Menu selection: Project -> Source Code Engineering -> Import Files Directory dialogue box opens for you to select files.
I have 'reverse engineered' many C++ projects, large and small. You WILL spend significant time on cleaning up. It will depend on the quality of the project, its structure and code.
Then you can generate a documentation report on it (Project->Documentation) which I have found very useful, the HTML report, to navigate the code.