That's not a programming question, so I moved it.
And well, what do you mean by " in the library folder"? Have you followed the instructions given in the wiki, for example?

Yes I went through the protocol and followed the instructions step by step
I'm used to adding libraries now  so I am using the 'libraries' folder under 'Processing' as usual :)

here's the whole story (console)

No library found for shapes3d.utils
No library found for shapes3d
As of release 1.0, libraries must be installed in a folder named 'libraries' inside the 'sketchbook' folder.

I tried to use an example given with shape3d and installed guicomponent for it was needed
at some points of the examples (in shape3d) shape3d isnt recognized at all
I'm confused
would changing the name of the directory be of any use ?(they put the version number in the name but I got rid of it)

Is there some tricky thing I can do? Otherwise I'll do it again and again and again until it works ;) :))

Is there something special I must do in order to use the examples (that come along with the library) I mean moving them.... :/ at this point I guess I'm just wrong.

" so I am using the 'libraries' folder under 'Processing' as usual"
This sentence is ambiguous, at least for me. I have a Processing folder where I have the binaries of Processing, and, on another disk, a Processing folder where my sketches reside. And some other Processing folders, eg. with the source code of the software itself.

And, yes, you must have the same name for the main jar and the folder hosting it.

I've renamed the folder properly, it's working, thanks

Can someone explain this to me? I am having trouble finding and placing the shapes3d library as well; I feel that if I had the step by step procedure it would all make sense, thank you.

See the How to Install a Contributed Library article in the wiki.