Legion of effects with a SPIN

In Legion, now out on DVD, the future of mankind rests with the Archangel Michael (Paul Bettany) fighting against God’s angels of fury. Former effects artist turned director, Scott Stewart, looked to SPIN VFX to help realise 260 shots of digital angel wings, digi-doubles, set extensions and environments. We talk to SPIN visual effects supervisor Jeff Campbell about his work for the film.

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fxg: The wings are obviously a huge part Legion. What were some of your initial considerations in how they would be achieved?

Jeff Campbell: For us it was all about integrating the wings into the plate and how they would cast shadows. We had some wing experience from Max Payne. Our client at first was The Orphanage who unfortunately went out of business while we were still working on things. We didn’t want to stop and we loved the movie. Sony took it over and they honored our contract which was such a relief. The Orphanage had modeled the wings. I see that as a trend nowadays with the assets being built with production. In that way the director can have direct access to a modeler or texture artist in the production office. It was funny, they gave us leather pants and things like that for reference. But these wings had to repel bullets and be tough and look like kevlar, and on the other hand still had to look like feathers. There was a fine line between making them look tough and making it look like fluffy white angel feathers.

10May/legion/GM_0190fxg: What kind of technical issues did the wings throw at you?

Campbell: At first we thought we’d need a closed wing rig and an open wing rig, because it can be difficult to go from completely spread out to closed feathers. To rig every single feather on that rig would make it too heavy in geometry. So we tested the rig in some hero shots with textures. We also did some things on a per-shot basis like texturing where we needed to. It’s interesting in the quote – you quote texturing then rigging then modeling. It’s never really so linear like that. You’re always tweaking things right up to the last minute.

Tracking was also a major thing, especially in the fight sequences. These guys are diving and jumping on each other’s backs and we had to fit the wings in there. That was one of the challenges we had to face. For tracking, I found the best thing was to put some LEDs right at the base of the actor’s shoulder blades. That’s what we did on the final sequence. We used PFTrack which has the object tracking and camera tracking functionality. We had scans of all the actors and would do roto-mation match-moves of them. PFTrack would lock that geometry onto them and help us immensely. This let us cast shadows on the wings and generate shadows from them too.


fxg: What were some of the other tools used for the wings?

Campbell: The wings were modeled in 3ds Max and Maya. We did all the feathering on top of the wings. Rigging was in Maya. We had a hero or parent scale node. I find you can’t really keep ‘scale one’ for every shot – you have to customise that depending on the shot. We’d have to scale them up sometimes to make it work for the shot. We really needed a hero scale node that would not affect any animation down the road. Comping was all done in Fusion, with all OpenEXRs renders coming out of lighting.

10May/legion/DW_0001fxg: Some of the shots with the angels feature nice God rays. Was that hard to get the look right?

Campbell: Those transparency passes were brutal in rendering! But it really sells the feathers. You needed to see through them to the spine. There were very difficult rotos because you have this light that’s eroding your edges like crazy. And we had to put wings behind say an arm that really should be occluding this light, yet the arm is still eroded by the top lights. That was quite a task for 2D. It really helps when you add our own volumetric lighting on top of that.


fxg: What kind of digi-double work did you have to do?

Campbell: There were a number of shots, such as when the characters fly in, or one where they tumble out of a windscreen. Sometimes they shot the actors on wires, and it looked a little like they were on wires, so we had to replace them. It was easier for us to do a full CG Gabriel in some shots because we had a hi-res scan of him. I kind of like to cheat with digi-doubles, you know. Faces are hard to do in CG. I’ll get textures from different angles and re-project them on faces – tricks like that. For the Granny shot, it was actually her real hair re-projected onto geometry. We had built CG hair but I find that the time it takes to match exactly it’s easier to pull stuff from the plate. I come from a comp background. I’ve been an Inferno comper since the mid-90s. And for commercials we tend to do it that way too – you have to come up with fast solutions that look great. So we always try and use as many real elements as possible.

10May/legion/GA_0210fxg: The Granny shot is pretty memorable – can you talk a little more about that?

Campbell: I did the Granny shot climbing up the wall in Inferno. She jumps and smashes on the window blinds and hits a little light that’s on one of the cubicles in the restaurant. To make it work, we realised we had to build the whole environment. Getting the opacity right on the cloth was tackled right away, as was the dynamics on the blinds. Hair was an internal issue, so I just grabbed a few stills from her real hair and re-projected it onto my own geometry, brought it into Inferno, match-moved it myself. I put a little deformation mesh onto it to add some dynamics and nobody knows it’s actually 2D hair. It works for the shot.


fxg: How did you approach the matte painting work, especially in that final desert valley sequence?

Campbell: Juan Garcia was the matte painter. There were a lot of re-projections. We were surprised with what we could get away with using 2D re-projections and primitive geometry shapes to get a feeling of parallax. We’d block out shots roughly so the client could get a feel for it. The matte paintings were done in Photoshop, then we’d take the track into Fusion and re-project them. I’m a big believer in trying to finish as much as you can in 2D, so we’d take the geo and any kind of track information in 2D and doing projections there. In that way we can play with the live-action elements too.

10May/legion/RR_0345fxg: How was the sequence with the hundreds of flying angels achieved?

Campbell: Everyone thinks we had Massive for those shots, but we didn’t. Tim Sibley, our FX lead TD, had a flocking script that worked really well. We just did it in layers. You have foreground hero characters flying through frame which are keyframe animated. The others are done using animation cycles offset to make them look different. The challenge there was at the beginning they were supposed to be in a specific formation – in rows flying – then they break formation and fly down towards the camera. It was done using Maya particles and we added a lot of camera shake and real-world movement to the shots.


fxg: The director, Scott Stewart, knows a thing or two about visual effects. How did that help your work?

Jeff Campbell: It’s cool working with these guys because they’re all in the industry. Jonathan Rothbart, the overall vfx supe, and Scott were partners in The Orphanage. It’s so awesome communicating with these guys. They know what’s involved and what they’re asking for. At one point, they had to go work on Priest, so I actually lost a director and a visual effects supervisor! Joe Bauer came in for the last end sequence and he was great.

10May/legion/GM_0790fxg: Any other memorable shots?

There’s one of a guy nailed on a cross upside down with his skin boiling. The idea is that there is this acid underneath his skin that eventually makes him blow up which then blows acid toward camera and the acid burns everybody in its way. It was all CG fluid done in Maya. That’s what we do – gross things! That’s why we’re in visual effects.