Hello,
I use for the first time packp3d, and I see that it produces only one file .p3D.
Is there another way to produce an executable file, but conserving the files tree (with image, models, …)?
For example, I can imagine an updater module, which will download the changed files, and not one big exe.
The p3d file is actually an archive file, like zip or rar. You can use Panda’s multify tool to look within it (run it from the command line, and use “multify -h” to give you usage instructions). If you do, you will see the full contents of your directory hierarchy.
However, if your application is large and you wish to be able to download or update it incrementally, then you should consider the package system. A package is like a p3d file but it is hosted separately, and it can contain a greater variety of stuff (including compiled C++ code). Also, Panda can automatically download and update incremental patches for packages. When you use one or more packages, you will still build a small p3d file to kickstart your application that references most of the code in packages.
Building packages is more complicated, though. You will need to understand what a pdef file is, and you will use the ppackage tool instead of the simpler packp3d tool. The manual talks about this a little bit.
David
OK I will work on it, absorbing the manual, and try to create package, and understand pdef.
I see chapter on hosting package too. I think I have lot of read before be operationnal 
I will ask on irc if I got difficulties.
It seems to be a good way to do. Players will be updated when patches will be deliver.
Thank you anyway.