AHHH, found it...add the option ENABLE_OBSOLETED_FEATURES YES to your config.
It looks like it's in the base license (all versions of Creo), but there are several steps required to access it. Take a look at these two articles:
Help Documentation: Creo Parametric Help Center
Hear is a product idea requesting this get put back in the ribbon by default:
I just checked and I, too see the N-Sided Patch. We also have a PROE_FoundationAdv license, which, if I remember correctly, is advanced surfacing? Funny thing is, when I check which licenses are in use (Command window, command "ptcstatus") it doesn't show that license being in use, so how can the additional functionality by available? Odd.
P.S. I'm on Creo 2.0 M240.
I have that option too, did not spot it, I did not even realize I had it, but I have had Creo 3 running for ages now, I must have added it at some point, just don't remember. Just checked my Creo elements pro-5 config & that option does not appear there. Looks like this is a relatively new option. Anyway, now you have it working. Give it a go, it is very fiddly to use, but once you get the hang of it, worth the effort. Good luck.
So the next question should be...
Why is it obsolete?
And since it's obsolete, will it be removed?
And, if so, is it worth spending time learning something that is going away in the near future?
I certainly hope not. I have used this feature for years where circumstances allowed & just recently discovered a new use for it which will mean me using it even more. I don't understand the mentality of Ptc, this is a great feature that produces a nice surface, i don't understand why it is not a main steam feature like Boundary Blend or Sweep. There must be 1000's of examples where people have more than 4 sided boundary surfaces. I have used this feature with 6 sided surfaces to great effect. Like i said in my original post it should be nurtured & enhanced & respected. It is every bit as good as Boundary Blend, albeit fiddly to use but that could be fixed if it were developed & bought in line with the rest of the UI.
I just played with it and yes this could be very useful. Especially when dealing with a poor part import, or a file that will not STL without errors and you need to do a little cutting and filling to make it work. But for now I am glad it is there.