Question related to message actuators

Can anyone tell me some cases of where can I use a body-property message actuator and how?
How does the message sensor (that exists in another object) use the body-property?

Message sensors provide the body with the Python API. Be aware the body is always string.

A use case is pretty straight forward: Healthbar

Your “health manager” notifies a change on health (e.g. because it set a new value).
It can notify interested objects by sending a message with subject “health changed” and body with the (string) value of your “health” property. [Assuming you use a property to keep that value].

The Message Actuator allows you to do that without any Python code.

The other side(s) = the interested objects listen to messages with the subject “health changed”. They can do that with the Message sensor and subject filter “health changed”.

As you can receive any number of messages, you need the dynamic power of Python to process each of them.

Find more details in the BGE Guide to Messages incl. Healthbar tutorial

Without any python can I gain access to the body?

No, you can’t.

The answer is a question: What body of what of the messages do you want to get?

I was wondering since I met this issue and didn’t find more info. You helped me with your answer and I already found a workaround so thanks a lot!