I wanted to try to give a thorough response, because it seems that there is some confusion and some misunderstandings here. Also, I think we're beyond the need to use spoilers, it'll make everything easier and anyone who hasn't seen the movie yet is probably not worried about this detail - which is all over news sites anyway
Perhaps recreating it to look exactly like the old actor is still hard, though one would think photogrammetry could help.
Photogrammetry needs really high quality imagery to create good results. Think 50-100 8K digital photographs with perfect focus and even lighting, using the same type of camera with the same settings. Without that, the pattern matching across the images won't have anything to work with, and all you'll get is a big lumpy mess.
More importantly, matching the facial expressions of your CG model is where the entire thing gets really complex. It would be easy to create a convincing static image, but the character also has to talk and act.
So it wasn't possible to use photogrammetry in this case and that made everything much much more complex from the start.
But in any case you don't have to recreate the exact likeness to make a convincing character, it would just look like an uncannily similar stunt double, close but someone different for those who've seen the prior works.
I'm not sure what your point here is meant to be. The only way to do this was to aim for a 100% likeness of the actor, or forfeit CG completely and only use a lookalike actor. Disney made a choice to go all the way, because they must have felt that the time was right - they had the tools and tech and experience and the story has justified their use.
The thing is you can't tell me that the best of the best for humanoid characters is of so uncanny results unless you've got the living actor and can scan them right then and there for the movie. Again you don't have to exactly replicate the previous actor, just pass of as human, not some creature, unless that is the intent.
This is a point that I've already talked about, but let's go through this again...
First of all, Tarkin has worked for a very large part of the audience. I immediately realized that it wasn't working well and wasn't able to fool me, but I'm not a part of the majority here. I'm also specialized in facial modeling and animation, and supervised dozens of scan-based CGI human characters at work, so I'm probably quite sensitive to a lot of this stuff. But the same is true for most of you guys here at B3D, being 3D graphics enthusiasts; so you guys should also be counted as experts here, unlike the average movie goer.
Also consider that only hardcore SW fans would remember Tarkin's character, and have a fresh and clear mental image of how he is supposed to look like. These people would also know that the actor has passed away a long time ago so it has to be an artificial creation. That will immediately mess with the results, as sight is not just a sensory function - it involves a lot of brain work to interpret the image. On top of that, the ability to thoroughly read another human's face is a strong evolutionary advantage, so we all have a lot of unconscious processes at work; most of which isn't understood yet.
So, I'm quite convinced that even most of us here could be easily tricked by a CG human if we were seeing it under the right circumstances.
First of all, we shouldn't have any hint or knowledge of it being there at all. Also, the more 'generic' the face and the less complex the performance would be, the more convincing it'd get. Peter Cushing had an extremely characteristic face, almost caricature-like, whereas Walker for example had a more usual "handsome guy" look. Which is also why the two actors were usually getting the types of roles they had in these two movies as well in the first place.
Heck at least one of the actors was alive during filming and could be de-aged.
I've already explained somewhere that "de-aging" is an entirely 2D process that has a very limited range. You can't turn a 60-years old woman into a 19-years old younger self, the changes in the face, the expressions, the skin etc. are too extensive. Think about this process as something very similar to Photoshop retouching - you can remove tiny wrinkles and even some larger folds, skin blemishes and unwanted colors - but you can't re-sculpt the entire face.
Tron's clu seemed more convincing, minus that ending scene, you could tell it was cg, but the quality was quite good.
Perhaps you should see that movie again
because CG Bridges rarely works as well as Tarkin does in most of his scenes. If we're at Tron BTW then let me remind you of that one short scene with the young Boxleitner - granted, there was an interlace filter and lots of grading on top of the image, but that character worked much much better.
As I said the terminator face from salvation also looked very good and convincing, even superior to genisys.
That I completely disagree with
Genisys Arnold is really, really good, the other one absolutely not - at least IMHO....
Wouldn't surprise if characters with significant facial structure change or entirely fictional humans end up looking more convincing in upcoming games within the next few years, and doubt drastic changes would have taken place on the underlying tech.
Again, sorry but I don't really understand this...
Fast and the furious already set the stage. And didn't that come quite close to the actor's death?
As other's have already pointed out, FF7 was a very different case - they've already had most of a high-budget movie in the can. So it was a question of forfeiting most of that material and a large investment, or finding a solution that would still honor the deceased actor and his family, but also allow them to complete the film.
ps wow couldn't even tell on gladiator when I watched it!
Gladiator was a very simple 2D compositing trick, I think the footage is actually re-used from the scene where they first visit the Colosseum. Completely unrelated to CG Tarkin, it's actually a parallel with Red and Gold Leader's scenes.
