The practical and digital effects that made sandworm riding possible in ‘Dune: Part Two’. An excerpt from befores & afters magazine.
A signature moment in Dune: Part Two occurs when Paul Atreides (Timothée Chalamet) successfully learns to ride a sandworm, truly immersing himself into Fremen culture. “The sandworm riding was one of our first Zoom calls which Denis had with the heads of department in soft prep,” recalls visual effects supervisor Paul Lambert. “Denis pitched this idea of how, to actually get onto a worm, he would have to climb up a dune and call the worm. The worm would crash through the dune and then Paul would fall onto the worm. He would travel down through the sand and onto the worm, which was an absolutely amazing visual. But, we were kind of stunned as to how the heck we were going to do this given our want for a practical approach.”
“For Denis, it was extremely important that all the worm riding and all the scenes with the worm needed to be believable,” remarks special effects supervisor Gerd Nefzer. “Denis was concerned about how we could put this on the screen to make it believable, to make it look good, to see the speed of the worm, and the size, the huge size of the worm. Right from day one, right when we got the script and we had the first meeting, he said, ‘This must be good and believable, and that the audience would say, ‘Okay, we believe that, and we see the size, and we see the speed.’”
Working off storyboards and limited previs, the filmmakers decided early on that one thing would be clear—the scene would be filmed outdoors to give the appropriate sense of light. Initially, a recce was arranged in an attempt to find a suitable dune or dunes to film on. That approach changed when DOP Greig Fraser pushed for the moment Paul is on the dune to always be backlit by the sun. While one location served as a wide shot, the moment Paul plunges down into the sand as the worm breaks through would therefore have to be achieved with a bespoke setup, that is, not on a full-scale dune. Instead, production built a much smaller man-made dune in the UAE under which Nefzer placed steel tunnels and drums. A stunt performer attached to a wire would run above this setup. As the performer got close to the tunnels and drums, those would be pulled away, causing the faux dune to collapse.
“Sand is tough to work with,” advises Nefzer. “It’s kind of like water, it’s very, very heavy and you have to keep it under control because it’s going everywhere. But, we were able to build this dune out of three meter diameter and eight meter long pipes. We dug the hole out of our dune, placed these three cylinders under the dune, filled it, and made it look nice with wind machines and leaf blowers. We also rented three huge trucks from an oil company in UAE. They were really unbelievably big, and we hooked the steel pipes onto the trucks.”
As noted, the stunt performer would run on top of this man-made dune. On cue, Nefzer’s team would orchestrate the pulling out of the tunnels and drums by communicating with the truck drivers. The setup was highly successful. However, for the correct lighting to match the original dune, the stunt had to take place at a certain early time of day. And, once the dune was collapsed, it took a day to get everything back in place, meaning only one shot could be attempted daily. “The first four days weren’t successful and we were disappointed,” admits Nefzer. “But then I think on the fifth or sixth day, we got the right timing.”
“It took four attempts for us to actually do it, but what we got was gold,” adds Lambert. “Having got that footage, I was then able to extend the real photography with additional CG elements so that when we looked down, we could see the worm passing through.”
For the moment Paul slides down into the dune, a stunt performer was pulled down on a sled, which provided for plenty of practical sand kicking up around him. Further practical layers of sand and CG sand were added, too. It was kept deliberately messy, notes Lambert. “The idea was that you were never going to make it a beautiful shot with this because we always try to say, if we did this with a camera for real and up on the top of the dune and actually shot this, how much would you actually see because there’s going to be dust and sand everywhere? So that’s basically what we piled on, and it got to the point where we put on so much that you couldn’t actually see the action, so we turned it back a bit. The idea was to fully, fully immerse him in the sand and dust.”
When Paul rolls down the worm and places his maker hooks, Nefzer’s team built a platform that was 25 meters long and eight meters wide that was leaned against the studio wall. It allowed Timothée Chalamet or his stunt performer to jump on something practical, get the hooks in place, slide and stop.
A motion base fit for a worm
The next step was to depict Paul on the worm. A dedicated ‘Worm Unit’ was established to handle this work (led by the film’s second unit director Tanya Lapointe). Once Paul gets control of the worm and is able to use maker hooks to clasp onto the creature while in motion, production took advantage of filming in a more controlled environment in Budapest. Here, Nefzer established a worm riding motion base. “We set up a similar thing that we had done for the ornithopters on Dune: Part One,” outlines Lambert. “This was where we had the cylindrical kind of dog collar which encompassed a gimbal/motion base which had a section of the worm created so that the stuntie could actually stand on it and hold on to the ropes. The idea being that, to try and sell something as being immersed in the desert, you need to immerse it in the bright light and the bright bounce of the sand.”
This meant a sand-colored collar—‘sandscreens’—surrounded the gimbal, and would bounce light from all directions. Furthermore, the stunt performer on the gimbal was constantly bombarded with sand (to the point, says Lambert, that “he would start with a suit which was black and a bit sandy, but then by the end of the day, he was way more orange. So we did have some more continuity issues to actually try to deal with that.”) Some aerial plates of the wormriding filmed with a low flying helicopter were also captured and then sped up to match the right sense of movement. “Having that particular setup and then having Greig lens it in a way that was sometimes on a long lens—and then we would have the worm rise and twist and turn—made for a very dynamic kind of feel to the whole sequence,” says Lambert.
Nefzer’s motion base setup was also deliberately placed deep inside the ‘dog collar’ thanks to a specially dug hole, essentially so that the motion base and the performer was not up so high in the air that Denis would have trouble communicating with them. “I had learned that after Blade Runner 2049 and Dune: Part One,” notes Nefzer. “So we dug a big hole in the backlot and got the motion base into the hole. It really helped a lot.”
The motion base was constructed with a Lazy Susan-type functionality that allowed it to be turntabled around, always directing the worm skin to the sunlight. “That was mega-important for Greig Fraser,” says Nefzer. “One particular motion base rig was fitted with a separate hinge that allowed it to tilt 90 degrees, the idea being that Paul would hang off the worm skin until he could control the riding. Other configurations were made to handle different angles.”
“We have used motion bases on many other projects, but never with a worm on them,” continues Nefzer. “Usually with motion bases—which are high-tech, computer-controlled machines running hydraulic oil—you are running them in very clean environments. This time, every day, they were covered completely in dust and dirt. We were really scared about getting some failures in the computer or on the bearings, so we tried to cover all the joints and hinges and covers with plastic bags. Then of course we shot it outside, sometimes in the rain. I still have red dust on my motion base!”
Once Paul stands atop the moving worm, he is hit with rounds and rounds of dust pushed through wind machines. Much of that was there, practically. “I think the most dust that we used in one day was a ton of dust,” says Nefzer. “When my crew came back after shooting that, you couldn’t really tell who they were. They were completely covered with dust.”
The dust was made from bentonite, a substance used in the make-up industry. “The tricky thing was that we had to match the color of the Jordan desert and the Abu Dhabi desert,” describes Nefzer. “The Jordan dust or desert is very reddish and Abu Dhabi is not as red. It can also look different when it’s airborne compared to when you have it in the hand. The size of the ‘corn’ of the dust was also important. If it was too big, you’re not able to blow it like sand. We had three or four 70 kilowatt electric wind machines on Pettibones and on lifts and forklifts surrounding the worm skin. It was all about finding the right consistency.”
Facilitating Paul’s ride
Using the practical effects photography as a base, DNEG played a significant role in how Paul came to be riding the worm. This started with the shots of the character running along the dune itself before it collapses with the worm going through underneath. “Because they were constantly rebuilding the pieces of dune, we had to actually sculpt that for every take that they did,” discusses DNEG visual effects supervisor Stephen James. “We had some really incredible sculptors who did this by eye, and then that could blend down into our CG work.”
“What that allowed us to do was match the crest of the dune really precisely,” continues James. “It allowed our compositing team to go through and paint back frame by frame footfalls, dust kickups and things like that. Our effects team would actually have to go in and precisely match things like foot kickups and the collapse as well, and then extend that into the wider simulation. So, there was a lot of really challenging work from effects to lighting to comp, to really precisely hit those blends, because it was so important that we did keep that magic that was in those plates. There is that energy that is in a lot of these plates that we just had to keep or we would lose something that was just too important.”
Importantly, too, DNEG was able to use the information from the plates to directly inform its own CG work, such as, James mentions, “the way that light scatters through the dust and the way that the color and tone shift as light passes through. We took that practical photography reference into our full CG shots later in the film; everything we learned from those plates.”
For the subsequent moment of Paul falling down and onto the worm itself, DNEG was only required to do some minimal clean-up here of background seams or fans. That was because the shots were intentionally already heavily dust-filled. “We did add a little bit of grit to the sand just to add some texture quality to it,” says James.
Once Paul uses the maker hooks to cling onto and then control the worm, DNEG worked with the motion base plates. Notes James: “I think that was probably the most challenging portion because we had a lot of dust and sand on set being blown across the surface of the worm, that we had to make sense of it at a much larger scale. So if there was sand blowing on the surface on set, maybe that’s sand that we would add on top of our CG worm that was from previous sections where it was under the sand and that would be cascading through down the back of the worm. Or maybe there was a bit of history from a dune that was hit that was already in the air, so we’d always have sand particulate and dust history, and we had to think about what was coming and what was already happening in the sequence.”
The sandscreen dog collar motion base setup in Budapest provided major assistance to DNEG, too. “It really helped us to get the natural light of the desert bouncing up onto Paul and the worm,” says James. “We were using the sandscreen, whether it was in light or shadow, and matching to that in our lighting and compositing teams. So, if the sandscreen itself was maybe a bit darker, we would try to light the dunes in the background to motivate that.”
The wormskin Paul stands on was mostly replaced by DNEG’s CG worm, with the first film’s asset used as the starting point. “Obviously we didn’t get as close as that on the first film,” details DNEG visual effects supervisor Rhys Salcombe, “so we had to rework the first one to some extent anyway, to make it a bit more malleable in animation, in particular. Because Paul stands on such a tiny portion of it, we essentially worked with a nested approach on the worm. At its most macro level, you have an asset that’s relatively detailed. Then you extract smaller and smaller sections as you get towards the saddle, the part that he stands on. Then the smallest section was a replication of the set piece, which was based on our sculpt from the first film. We kept as much of it as we could in some of the shots, but we did end up with a CG version that we could use to replace it if required.”
A worm through the landscape
DNEG’s role in the sandworm riding sequence was also, of course, to realize the worm traveling through the sands of Arrakis, and to incorporate plate photography into their digital creature and environment shots. This started firstly with effects tests using their existing CG worm model from Dune: Part One, as Salcombe outlines. “Very early on we were told that 90% of the worm’s mass would be underground during the worm riding, which obviously affects the behavior quite a lot. We had to work out, if you have 90% of the kilometer long animal underground, what does that displacement of sand look like? Well, it looks like complete chaos when you simulate that for real. So one of the first things we had to come up with was a way of figuring out how to make it look aesthetically pleasing while also hitting that brief.”
The studio embarked on a series of wedge tests to establish how deep their effects container for the worm should be and how much sand beneath the surface should be moved. Quickly they realized that a deep container made for a constant explosion of sand. “So, instead,” says Salcombe, “we went for a relatively shallow container. It led us to doing a rapid prototyping of our effects for worm riding with a ‘ball pit’ process.”
“DNEG came up with a great way in which they could visualize it and show myself and Denis as to what they were thinking by basically using particles the size of beach balls first as a quick and cheap render to be able to show what this is going to do,” says Lambert. “I then talked Denis through how the beach balls then became tennis balls and then became little grains of sand. It was a great way to have the director involved.”
“The ball pit was exactly what it sounds like,” states James. “Instead of grains of sand, you’re simulating with beach balls, basically—just a low resolution simulation. Denis and Paul really insisted on it because it was really important to them we weren’t wasting time adding details to something that just didn’t have the right feel to it or the weight to it or scale to it. We could really tell pretty early on from these low resolution sims that it had that right feeling.”
“Paul and Denis were also okay to let the dust and additional sand do whatever it did,” adds James. “So, if there was a big burst of dust and sand that happened naturally in the simulation, they would just leave it, and it may cover a lot of really expensive, beautiful simulation work, but I think on the whole, through the sequence, what it created was something that it really felt quite natural. Visibility would come and go throughout the sequence and other worm riding sequences. It just created a real sense of danger coming and going throughout.”
One of DNEG’s main challenges early on, too, was finding a look for different levels of sand and dust going from chaotic ‘worm sign’ (where the sand debris is visible on the surface) to essentially having the worm melt a dune as it goes through the sand. “Then as Paul gets more and more control,” says James, “this really chaotic worm sign and all the stuff that’s happening around the worm, needed to become more and more calm over time. We needed to visualize that early on and really understand how things were flowing before we pushed through into the up-res.”
Ultimately, DNEG’s tests determined that their worm would be moving around 300 kilometers an hour through the sand (the animation team was led by senior animation supervisor Robyn Luckham and animation supervisors Ben Wiggs, Hitesh Barot and Omkar Fednekar). The simulations would be handled mostly in Houdini as Vellum simulations, with renders done in Clarisse (including at IMAX-level quality). “We had some tools in-house for point replication and data management, which were important for when you’re dealing with that larger scale of sim. It meant that we could get those simulations up-res’d from the ball pit and then use the point replication tools to up-res even further. When you’re dealing with sand that’s so fine, it essentially behaves like a liquid. As many points as you can throw at it, the better the result will be.”
Read the full issue of befores & afters magazine on Dune: Part Two, available here.
Stay up-to-date with VFX news -> Subscribe to befores & afters weeklies, and get a free Tech of Terminator 2 ebook!
