A new chart creates a new model

Question

I create a new Analysis Model , and then a new diagram of using Simple Uses Cases inside it.

Why does it automatically create a new model called same - Simple Uses Cases at the same level as the Analysis Model ?

I would like to understand the rationale for this behavior of Visual Paradigm.

Update 1

I created two use cases, and for each, a sub-diagram of a type sequence diagram:

Why are these models empty ( Simple use cases , UseCase sequence diagram , UseCase2 sequence diagram )? What are their customs? Why are they created at the root of the project, regardless of the depth of the chart being created?

Answer 1

How does Visual Paradigm work? (based on its documentation)

Visual Paradigm offers the so-called "Models" so you can organize yourself. Just so simple.

If you follow the link below, this will help you:

"For small projects, it would be easy to use the Diagram Navigator to manage it. However, for a medium to large-scale project that contains a significant number of diagrams and model elements, it would be better to use the Model Structure view to organize the project."

https://www.visual-paradigm.com/support/documents/vpuserguide/12/74/6302_organizingdi.html

The image below also shows the available models:

So why does he create an analysis model for my use cases?

If you look at the parameters of the models that it gives, you will see that the analysis model is best for grouping use cases.

The reason for this is simple and also answers one of your questions.

Answer: The use case (in this case, the diagram itself) serves to simulate the EXTERNAL BEHAVIOR of the system, which means how the subjects interact with the system.

This is a step taken in systems analysis. As for the design, implementation or deployment, other available models.

Since you are not modeling the process, you would not choose the last two options.

So, to answer these questions ...

Why are these models empty (simple use cases, UseCase sequence diagram, UseCase2 sequence diagram)? What are their customs?

... you must understand the semantics of each diagram. To do this, I advise you to read any link on the Internet, for example http://www.uml-diagrams.org .

But, to be short, these diagrams are not built independently or automatically. Visual Paradigm will never do this, simply because it does not know how you plan or implement your use case (in the sequence diagram).

And answer your last question ...

Why are they created at the root of the project, regardless of the depth of the chart being created?

It is simply because of the organization that I explained above.