HOW A DRIVABLE BUGGY WITH A GIMBALLED SADDLE, AND VFX, MADE IT POSSIBLE IN ‘DOLITTLE’.
When Stephen Gaghan’s Dolittle hit cinemas earlier this year, fun b-roll was released of its star, Robert Downey Jr., aboard some kind of mobile rig that was standing in for one of the animals.
It turned out this was a rig built for filming moments in which Dolittle rides the ostrich Plimpton (voiced by Kumail Nanjiani), a CG creation by MPC. Riding rigs and gimbals are common for when a live-action actor interacts with some kind of creature that will later be accomplished digitally, but I wanted to find out what the very particular challenges were in going from such a rig to the final visual effects shot in the film.
Enter visual effects supervisor Nicolas Aithadi, who shared production VFX duties on the film with John Dykstra. Here, Aithadi runs down how MPC handled the ostrich-riding shots, including the pre-production animation involved, the shoot with the gimballed rig, the meticulous matchmoving and the simulation of feathers – including what almost made him cry…
The toughest thing about making RDJ ride an ostrich
Nicolas Aithadi: The main difficulty with the riding shots is that we didn’t have any wide shots where we could use a CG ostrich and a CG Dolittle. We had quite a few shots, instead, in the Queen’s chamber and at Buckingham Palace, and in a couple of shots that didn’t make the final cut, where Dolittle was close-up riding the ostrich. So we had to find a way to have Robert Downey Jr. actually riding something on location or on stage that we could later replace with the CG ostrich.
With special effects [Dominic Tuohy was the film’s SFX supervisor], we came up with two techniques. First, they devised a buggy with a driver and a saddle that Robert could sit on and hold some reins and pretend to be riding an ostrich. The saddle had a gimbal set-up that could actually be ‘animated’ (more on that below) and had some sway to it and some rolling to simulate the body of an ostrich.
The other rig was more akin to a swing. One side was the saddle on which RDJ was sitting and on the other side you had a couple of guys dressed in green rotating and animating that swing.
Pre-animating for the gimbal
Whenever you are using gimbals they can be very rigid systems, so it can be difficult later to replace them with a very organic creature. So what we tried to do in those cases was give a certain amount of information to special effects so they could devise a system that would give us the ‘beginning’ of some motion that was close to the motion of the animal itself.
That meant way before we even started to build Plimpton we actually created a lower resolution ostrich in pre-production that we could animate with walk cycles and run cycles and trot cycles that we could give to special effects. They could take some of those movements and interpret it mechanically on the gimbal.
Selling RDJ’s interaction with the CG ostrich
One thing that helps visual effects is always interaction and contact. In fact, I try to not avoid contact in any shot. If I actually can add contacts, I will. Psychologically it’s what makes things work together.
That meant whatever Robert Downey Jr was touching on the rig was tracked and was where we would we have the CG ostrich. We tracked his legs and his butt touching the saddle.
Because we had Dolittle fully CG in other shots, we used the digi-double of RDJ to help with tracking; we also had a lower resolution CG version of the gimbal that we would track onto the gimbal from the set. Then, we would take the CG Plimpton model and we would make sure that where the gimbal was contacting with RDJ that CG Plimpton’s body was also contacting with the digital double that was match-moved to RDJ. And if we had to change the model to accommodate that a little bit, we would, either by changing the model or by deforming the body rig.
The hardest thing was the hands. The gimbal didn’t have a neck, so we had to be creative sometimes with the arms and the hands of Dolittle. Sometimes we replaced an arm or lost an arm if it wasn’t vital, visually, and it was creating problems. At one point we just decided to put some reins on the ostrich. If we had Robert’s hands floating in mid-air in the shot, we would justify it by having this red and white rein he was holding.
Hiding behind feathers
The main advantage we had when it came to Plimpton was his feathers. We had a riding set up with the giraffe as well, but the giraffe has very short hair, so there was nowhere to hide there, whereas Plimpton has a fluffy body with very big feathers. So we could hide some of the issues in there because of the secondary animation of a feathers.
As long as you do running and trotting, it works pretty well. The most difficult thing was when Doolittle was on Plimpton and then coming off Plimpton. One thing that actually helped us is that RDJ, he did it in a very dramatic way where he was nearly falling off the ostrich with panache.
A good example is when they arrive in the Queen’s chamber and Plimpton does this circular movement while Dolittle is coming off of him. I was very concerned when I saw the material when we shot it because I was thinking, ‘Oh my God, I don’t know how Plimpton’s going to be moving in there.’ But then when we did it, it actually was surprisingly very successful. Again, using feathers to aid with contacts was a great help.
The animation approach
To get Plimpton’s overall animation, we first obviously looked at a reference. We did look to see if there were actually people riding ostriches. We realized that in the Emirates, they have an ostrich race with jockeys.
But we were looking at them and they didn’t look very cool. They actually look silly when they’re riding the ostriches. They’re very much on the back of the butt of the ostrich and they’re leaning forward a little bit, it’s not a really elegant position. But Dolittle needed to look like a British gentleman, so it needed to look more like he was riding a horse.
The other thing that we were trying to convey was that Dolittle wasn’t forcing the animal, that it wasn’t a life of servitude for Plimpton. And when we were looking at the races, it doesn’t feel natural. It feels like maybe these guys shouldn’t be on those ostriches…
Rendering those feathers
Oh man…the feathers. That really was a nightmare. MPC has done fur for a long time, back to 10,000 B.C. where Furtility was developed. Feathers were made on a CG quill on which we grew a single hair that accumulated pieces to look like a feather. A feather is really a bunch of hairs lined up next to each other.
The challenge was that ostriches have these really weird feathers where they’re all very loose. It almost looks like a quill with very loose hair with no structure. It’s a very confusing object in real life. So to try to do that in the computer was a bit of a struggle – we had to use the Furtility system and hack it a little bit to try and deform the feathers way more than you would when you do a normal animal.
Rendering was great – it rendered very well in RenderMan and we’ve got some really nice shading on the black feathers. We got some very nice anisotropic reflections, too.
The feathers took quite a lot of time, but then, the worst thing happened is that we had to do Plimpton in the water! That made me cry a little bit…
Because of the work that had been done on Jungle Book and Lion King, Furtility interacts with water really well. But again, the same issue that we had with dry Plimpton, we had it with Plimpton in the water. It’s like when someone puts their hair in the water, it goes in every direction, it’s very loose. We had the same problem with a dry Plimpton, but it became 10 times more complicated underwater.
It was very difficult, but we had a group of amazing tech animators working on that issue and they managed to do a great job. The shading team also did an amazing job to deal with the wet look of the feathers.
In summary, feathers on ostriches: they’re not the easiest.
Source : https://beforesandafters.com/2020/04/23/what-happens-when-you-need-robert-downey-jr-to-ride-an-ostrich/