Hi there.

Do someone knows a tutorial or guide to make an inflating text effect?

Cheers and thanks in advance!

As a new user you might not be aware of the “second” forum for Houdini. It is called od|forum.

I did a search on that forum for inflate and found this link with an example file.
http://forums.odforce.net/topic/21483-how-can-i-inflate-cloth/?hl=inflate [forums.odforce.net]

I am still not sure how the technique works but you may want to start there.