Dennis Muren interview: Terminator 2’s VFX

At Industrial Light & Magic, Dennis Muren has worked on some of the most eye-popping movies of the past 40 years. Beginning with Star Wars in 1977, Muren has gone on to win a stunning nine Oscars for his visual effects work – often shared with such industry colleagues as Richard Edlund, Carlo Rambaldi and Phil Tippett.

For the purpose of this interview, though, we’re focusing on a landmark in CGI: 1991’s Terminator 2: Judgment Day. As we already saw in our main feature this week, James Cameron’s sci-fi action sequel took all sorts of risks by dabbling in computer-animated techniques that were barely tested in the early 90s. Cameron’s previous film, The Abyss, had contained one CGI sequence, which took so long to get right that it delayed the film’s release by several weeks.

With T2, ILM had to complete around 50 individual CG effects shots – a considerable number for the time – and all within a strict time limit. As Muren himself points out, while T2 also relied on the stunning practical effects work created by Stan Winston, the movie would have fallen apart had ILM not been able to deliver on its promise to create a shape-shifting assassin made from liquid metal.

As we now know, ILM pulled it off, earning Muren his eighth Oscar win and paving the way for other, similarly ambitious digital effects still to come. So with the newly restored, 3D edition of T2 out now on disc in the UK, here’s our full interview with the great Dennis Muren. It’s worth sticking around to hear what he thinks about the future of CGI in movies, too…

The quality of the film means you can’t even tell how tight the schedule was behind the scenes.

It was very hard. The most expensive movie ever made at the time, and a very long schedule – I don’t know what it was, but over a hundred days. But that’s what it took to get Jim’s vision on the screen, and just make sure that it happened.

It was so cutting-edge in terms of digital effects that you weren’t even sure that they would work, I read. 

Oh yeah, that’s right, that’s right. But I was pretty certain, because a lot of work had been done with reflective figures in computer graphics – that’s a much simpler problem than having to put skin on something, you know, to make it look like an animal, a dinosaur or something like that. But the flexibility, making a walking character that looks like it’s made out of mercury or chrome, and making it look like it has weight and actually in the shot is what was really extremely difficult. That’s what was successful. And it took us a long time to do – we spent months and months on that show. I think it was 52 shots or something like that. 

I found a behind-the-scenes picture the other day of Robert Patrick on an LA street, just in box shorts. He has a felt pen grid drawn all over him. I’m guessing that was you capturing reference material for the CGI.

Robert was good. He came up here – that’s actually behind ILM in Orange County. He stripped down, we put a camera on the side of him, so in some shots he had a grid behind him. Steve Williams, the animator, studied that and discovered that he’s got a little gait to him – he moves in a certain way that nobody else does. It was then that we started to realise how incredibly difficult it is to do a person. I don’t think any of us quite knew that before – how one person is different from another. It’s based on their weight and inertia – all sorts of things. But without that gait, it didn’t look like Robert Patrick, and Steve really managed to follow it perfectly so that it looks just like it him.

Robert was great, too. He said, make sure none of these photos get out, because it’ll be very embarrassing! 

Do you remember which scene you would have tackled first, perhaps as a proof-of-concept?

No, I wish I could. There were so many different things we had to solve. It may have been close to that walking shot, you know – but I’m not really sure. I remember the last one, which is the last shot in the movie, which is looking down on all the [molten steel] and you see the [T-1000] face coming up. That was the last shot we did. 

And how close to principal photography was that? I understand you front-loaded quite a lot of the effects.

No, no. We didn’t do any front-loading. We did tests, but based on story boards. I showed stuff to Jim all the time so that he could understand the concept. We showed him the wire frames. I did that all the way through the shoot so he could understand it and be comfortable with it. 

So how far into post-production were you rendering these shots down?

Immediately after we started shooting. They were great, because they put the effects shots right at the beginning of the schedule, so maybe the first shot we did was the storm drain, with the T-1000 walking out of the fire. That may have been close to the beginning of what we were doing. Then for the next two or three weeks we got a lot of work. We got the kitchen scene in the kid’s house – we did that right at the beginning. So we had a good bunch of scenes we could go away with and start we working on our shots.

I read there was talk of using practical effects as a fallback option – in case the CGI didn’t hold up. 

Oh yeah, they had to. And a lot of that stuff was Stan Winston – he had a whole group of people that did a lot of it. The robotic arm, the heads. Not when the [T-1000] is coming apart, but when it’s wiggling around – all that was full-size stuff. But I don’t think that they could have gotten much farther with that because it had never been done before with robotics. It probably would’ve been impossible to do. Everybody’s working on the cutting edge. I really wanted to come up with shots that had never been seen before, that could never have been done any other way. That’s what sort of knocked people out about it. That’s what became more visible to everybody in Jurassic Park – that was the one where they all looked at it and said, “Oh my god.” But most of that stuff was going on in T2. 

With T2 and Jurassic Park, do you think the reason those films hold up so well visually is because of the hybrid of practical and digital?

Well, I think that’s part of it. But I think it’s because you’ve got some great directors, and a great team of effects people with all different skills, all wanting to do something that hadn’t been done before, and not all film people. I mean, a lot of my crew hadn’t worked on movies before; they were more computer science. They just needed help, a direction of where to go. And I can add the cinematic feel to those shots so they look right, and Jim came up with these phenomenal ideas. Steve in Jurassic Park – he took it to the next level.

I think what’s going on now is that people are copying what we did, so it’s like a xerox of a xerox of a xerox. It’s not real anymore, it’s not the same anymore, and we’ve seen it before. I wish there was more originality, but it’s very hard now to come up with something new. So many things have been done. 

What was the most difficult shot to achieve in T2?

There were many of them, but maybe that last shot in the film – where he’s bubbling up and boiling. Turning inside out in the molten steel. That took weeks and weeks to render, and the resolution on it – we were trying to make it 2,000 lines across to be able to get the reality right there. I had to do a lot of that at less than 1,000, just to get the render done in time to be in the movie. Some of the frames went down to Silicon Graphics, some of them went to universities across the country, you know. We had connections with render farms here, render farms there, and then we could put all those frames together to get that shot. It was a nightmare, that one.

I spoke to Stephanie Austin, the co-producer, and she said that every mainframe in California was used to render these, basically.

Yeah, for that shot. Most of the others were done well internally, and we bought a lot of equipment and stuff like that. But going back to what you were asking earlier: it’s not like there was a backup if the CG failed. There really wasn’t for that. If we hadn’t made the CG work, or Stan hadn’t made his stuff work, then Jim wouldn’t have had a movie – and he knew that. Whereas with The Abyss, the film he made before, he could have cut that scene with the pseudopod out and nobody would have known the difference. He was taking a huge chance, we were taking a huge chance. 

So that last shot, the movements going on in there are quite complex. So was there a special piece of software written to do that? 

There was some, but the main skill with that stuff is really it being hand animated. We tried writing some special stuff for it, and for some other scenes, and sometimes it worked, but often we’d animate it key-frame by key-frame. The thing that a movie is, it only has to work one time, for one shot. A lot of the effort of writing software that can be used over and over can end up taking forever, so many, many times on the film, we just ended up having something be hand-animated. Steve was really good at that. 

That might be something that people don’t realise – the handmade aspect. When people think of digital effects, they sort of think of pressing buttons, or that it’s somehow automatic.

Absolutely. Everywhere, every step of that. The original CG look for the chrome guy looked terrible. Jim said he wanted him to look absolutely perfect – clean and everything, and flexible and changing shape. And I just thought, no, you don’t want that, because it’s not going to look real. You never see that in real life – it’s going to look like an effect. So I went in and muddied it up a little bit, so that the surface isn’t 100 percent reflective. The light’s scattering, it’s a little dirty, so even looks reflective and perfectly clean, if you look at it closely, it’s really not at all. That’s what anchors it into the shot.

You see it a lot in movies, where CG doesn’t look right, because they didn’t understand the importance of all those things that go into making something real. 

It is the details. One of the parts I love is the T-1000 in the helicopter, and you see as he gets in and says “get out”, you can see the pilot’s reflection in the T-1000. It strikes me that the reflection is something you could have avoided, but it sells the shot, a detail like that.

Yeah, well that was the plan. That was my idea. We were setting the shot up, and I said, Jim look at this – we can get this reflection in here of the pilot. He said, you’re right, that’s great, let’s do it. And it was true all the way through – when the liquid is coming together in the steel mill, and it starts rising up and reforming, you can see all the sparks falling down reflected in it, behind the camera. All that stuff is the same thing – it ties it together, keeps everything looking real and more frightening. It’s the detail, and we’ve been doing that detail stuff since the original Star Wars. The attention to detail is one of the things at ILM.

At ILM, from the late 70s to the late 80s, you went from computer-controlled cameras to full digital effects shots in less than a decade. When you look back on it, it’s a very fast evolution. Have they evolved at a similarly fast pace since, do you think?

Oh no, not at all. It goes in spurts, where technology and artistry all come together. That was the introduction of computers for controlling motions, but what they’re doing in car manufacturing with computers, that’s gotten better and better. But the stuff that’s going on with computer graphics, that kind of [peaked] sometime in the 90s. From then on, it’s more incremental, so now we have computer-controlled motions, and being able to get people to feel more like they’re walking without having to animate them. That’s happening, but I think we’re losing the feeling of it being made by people, you know? I think films always want to look like an efforts gone into everything you’re seeing. The work the people are putting it. You can see it in acting and lighting and photography and editing – you can feel the people working to make this. If computer graphics ever get to the point where they look too much like you’ve pushed a button, then it’s going to get very dull. You can sort of see that now in some places.

There’s a lot of talk lately about all-CGI characters and the uncanny valley. Do you think that’s something that CGI will overcome, in time?

You know, maybe, to some extent. But again, you can’t push a button. The human being is so complicated that it’s going to be really hard to get all that emotion and life into a CG character. Getting skin right is so complicated. At some point it will happen, but it won’t be through button pushing – and if it is button pushing, it’ll look very boring. The thing that people don’t think about is, when you go to make a movie, when you do the live-action part of a movie, we’re all trying to do something that hasn’t been done before. The actors are trying it, the directors are trying it, the camera guy’s trying to do it. I don’t think you’ll find any kind of computer program that’s going to try to do something that hasn’t been done before, unless you get into AI of some sort, and then who knows what the heck you’re going to get? It’s always going to be people pushing it, or you’re going to get a copy of what you’ve seen before. 

Well yeah. And when you get into the realm of AI, you’re getting into the realm of The Terminator, ironically!

[Laughs] True!

It all goes full circle in the end! Dennis Muren, thank you very much.

Terminator 2: Judgment Day is out now.