Todd has never, ever said they are using a brand new engine. For a year or more after Fallout 3's release, all we knew about what Todd and his team were doing was that they were
revamping the Fallout 3 engine. Unless they decided to scrap all of that fairly recently, they are not using a new engine. I wish these news sources would get their facts straight for once.
I feel I should post my excepts from Electronic Gaming Monthly's interview with Todd Howard again:
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http://www.gamesas.com/index.php?/topic/1118503-official-tes-v-speculation-thread-68/page__view__findpost__p__16443867
So I went down to Borders to find the new issue of Electronic Gaming Monthly and read the interview with Todd. Wow, that was a really good interview. So good, in fact, that despite sitting down and reading it all in the store, I still bought it just so I could read it again in the future. I suggest anybody who loves Todd or just loves Bethesda find it somewhere and read it. It's about 5-6 pages long.
Here are some quotes:
Interviewer: So are you happy with your progress [on the next project] so far?
Todd: Yeah, it's awesome, I'm ready to show it. It's a much bigger jump than Oblivion to Fallout 3. Much, much bigger in terms of fidelity, stuff on the screen, everything. I'm hard-pressed to think of a part we haven't ripped out and replaced. Rendering, animation, AI, interfaces, everything. New scripting language. We would take chunks out at a time, rework it, and put it back in. We need to have a stable codebase that's always up to prototype things.
And here's that part Controlled Chaos was talking about where Todd "almost let it slip:"
Todd: [continuing]...But I still sit down to play Oblivion, I sat down a couple weeks ago to play Shivering Isles, just to play again. I have a lot of fun in that game still.
Interviewer: I remember you told me a while ago, that before you make a new game in the Elder Scrolls series you go back and play all the previous games.
Todd: I don't play them all, I'll go back and look at them.
Interviewer: So it may have been just coincidental you were playing Shivering Isles?
Todd: No it- it was coincidental.
Interviewer: We're not giving anything away here?
Todd: [Smiles a knowing grin. Politely refusing to speak.]
Interviewer: Okay. You have to be careful what you say to me, because I remember everything.
-Interview ends-
I personally don't think he came close at all to letting it slip. Seems to me it really was coincidental, even though he's almost certainly making TES V. :shrug:
And he talked about how hard it was making Oblivion for the next console generation. Part of what he said was:
Interviewer: Speaking of, shipping Oblivion for the new consoles was tough.
Todd: Yeah, that was a rough time. That was a mad technical rush into the unknown for us. We definitely had our ducks in line to try and make launch. We found out there's a good reason people don't do 200-hour RPGs for console launches. The fact that we only missed by 4 months is...
Interviewer: It's pretty remarkable!
Todd: I think it's remarkable, to be honest... Before they launched, we probably had final hardware for four months.
Anyway, those quotes are all a really small part of a long, really good interview. I highly suggest you guys go read it.
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So, yeah, while they're heavily revamping the engine, they haven't actually gotten a new one.