The Art of VFX

WHITE HOUSE DOWN: Martyn Culpitt (VFX Supervisor) & Mark Wendell (CG Supervisor) – Image Engine

Martyn Culpitt started his career in visual effects with the LORD OF THE RINGS trilogy, then he worked on films such as VANTAGE POINT, INVICTUS or THE GREEN HORNET. He joined Image Engine in 2012.

Mark Wendell is in VFX for over 20 years. He worked on films like SHREK, ALICE IN WONDERLAND, SPEED RACER or PROMETHEUS.

What is your background?
Martyn Culpitt – Visual Effects Supervisor // I have been working in the Industry for over 20yrs. I initially started my career in film set construction at Marmalade Vision in Wellington, New Zealand in 1992. I soon realized I was more interested in the digital world so changed my job and worked my way through the editorial department of the company, becoming Senior Editor within the first few years. Following my interest in visual effects, I moved to the TV, film and visual effects industry as a 2D artist working on films such as THE LORD OF THE RINGS trilogy, TROPIC THUNDER, TWILIGHT, ANGELS & DEMONS, INVICTUS, SALT and THE GREEN HORNET. I was asked to join Image Engine to work as the Compositing Supervisor for R.I.P.D. in 2012. I had always wanted to work on creature films and it was a great opportunity to expand my experience even further.
Since I started in the industry, I have always tried to push my work and keep learning every project, my goal was to one day become a Visual Effects Supervisor. When I was given the opportunity to work with Roland and the Team at Uncharted Territory as Visual Effects Supervisor on WHITE HOUSE DOWN I was thrilled.

Mark Wendell – CG Supervisor // I’ve been in the vfx and animation biz for over twenty years, wearing many hats, including CG supervision, lighting, compositing, pipeline, fx, tools development, layout, and I even have an ‘animation supervisor’ credit! That’s one of the things I like about CG supervision, frankly, is that it’s an excuse to do lots of different jobs throughout the pipeline. I started in this business back when there weren’t any schools for learning CG, and in fact I have a biology degree, so everything I know about CG was self-taught and learned on the job.

How was the collaboration with director Roland Emmerich?
Martyn Culpitt – Visual Effects Supervisor // Our collaboration with Roland was a very smooth process. Working through Marc and Volker we had direct feedback as soon as we needed it, so there was no wasting time. Roland always gave concise feedback and direction, but he would listen to us and appreciated our ideas, which helped us take the shots to the highest level we could together. It did honestly feel like a collaboration rather than Roland just giving notes.

What was his approach to the visual effects?
Martyn Culpitt – Visual Effects Supervisor // Roland, Marc and Volker had done a lot of previs for the film; most films do as it saves a lot of time in the end. On WHITE HOUSE DOWN, It felt like Roland took it to the next level where he would sculpt and design each camera and shot in previs and even further with the team at Uncharted Territory once they had completed filming, before passing it off to us to create the final shot. By the time we started working with them they had pretty much locked down every camera angle and shot. This gave us time to work on the more important details of each shot and given the time constraints we had this was ideal.


How was the collaboration with Production VFX Supervisors Volker Engel and Marc Weigert?
Martyn Culpitt – Visual Effects Supervisor // We had a great collaboration with Marc and Volker, it felt like right from the start we were very much on the same page and our goals we very similar. ‘Make the shots as best and as realistic as we can within the time frame we have’. The White House is such an iconic building and has such a unique look to it so every detail had to be exact and photo real. The goal as always in VFX is to make the work we do as invisible as we could so the viewer isn’t taken out of the movie. I think working with Marc and Volker we were able to achieve this on every level. We had a lot of shots to delivery in a very compressed time frame. We really needed to get feedback and direction as early as we could in the process so would send very early versions of our shots to Marc and Volker, rather than waiting to polish the shots. They really appreciated us doing this as it gave them a lot of creativity at an early stage. This enabled us to get a lot more done and to make sure the shots worked when they were cut into the film. We would then push the shot through the pipeline and get it back as fast as we could to get final notes addressed.


What have you done on this show?
Martyn Culpitt – Visual Effects Supervisor // We created nearly 100 shots. The shots were in the Takeover and the Aftermath sequences. The Takeover sequence is just as the terrorists took over the White House and the national guard, reporters and civilians start to congregate on the white house lawn. In the Aftermath sequence our work ranged from blue screen plates, where we had to add CG White House grounds and the Washington Monument, to our biggest shots where we had to create full CG Environments for both the White House and surrounding Washington City with jets and helicopters flying around.

How did you create the three helicopters?
Martyn Culpitt – Visual Effects Supervisor // The Initial helicopter asset was created by Luxx Studios and handed over for us to use. We had to do extensive work to bring it into our pipeline and be able to use our shaders and the textures with our renderer 3Delight. We also had to re-rig the Helicopters so that we could make the landing gear and all other aspects of the chopper move the way we wanted it to.

Mark Wendell – CG Supervisor // Amusingly, we were looking into generating some organic variation between the three helicopters, when we did a bit of research and found out that they are “supposed” to be identical. The US government maintains the fleet of presidential choppers in pristine and identical condition, and scrambles their formation upon takeoff, in order to hide the president’s location. Apparently this is referred to as the presidential « shell game », but for us, it was an excuse to use the same asset for all instances of the chopper. Seriously, though, with minor variations in things like rotor speed, everything looked great.

Can you tell us more about their animation and the renders?
Martyn Culpitt – Visual Effects Supervisor // The animation was based on the actual previs. Roland, Marc and Volker did a lot of work early on to make sure they had the movement and look of the each shot. We strayed a little from this but most of our animation is based on the previs movement. Obviously once you have that base movement you then add and tweak the subtleties of the movement so that it feels right, once you get all the other assets and environment work done. We used 3Delight as our main renderer with full rayracing. We ran into some issues with noise in our renders and the guys at 3Delight were great about responding quickly tweaking and adjusting the renderer and our shaders to get it fixed up and looking great!

Mark Wendell – CG Supervisor // We’ve been experimenting with a fully ray-traced physically plausible approach to shading, and WHITE HOUSE DOWN was the second show that proved to us that this is the way forward. We worked closely with the folks at DNA Research to solve some noise artifacts and memory consumption issues early on with 3Delight, but in general this was a great experience for us, and we’re continuing to refine our shading workflow in this direction.


What was the most challenging aspect about the helicopters?
Martyn Culpitt – Visual Effects Supervisor // The biggest challenges we faced were getting the reality of the light and environment reflections, and the movement. Each shot we had to be tweaked so that we got the photo-real look we wanted.

Can you explain in detail about the White House creation and its environment?
Martyn Culpitt – Visual Effects Supervisor // Having to create a fully CG environment is one of the hardest things to do in VFX. Especially with such a well known building as the White House, its surrounding grounds and Marine One helicopter. We initially received assets from Method, Luxx, and Prime Focus World, each of which needed extensive work to be able to use them in our pipeline. We spent a lot of time re-linking and adjusting textures, then building our own shaders so we could get the matching look of the assets. Once we had the match, it was then up to us to push them around until we got the approved look that Roland, Marc and Volker were happy with.
Method gave use the White House and the Tree assets. The White House is such a hard thing to create; it honestly feels like the paint on the White House has its own unique quality, it feels like it emits light. The shadows and ambient occlusion plays very differently than any other building. This is very difficult to emulate in CG and especially hard to match to references. We had to do a lot of manipulation to get it to look exactly the way we wanted.

The Environment had over 800 trees, each having many hundreds of leaves, which had to interact with real world forces and be photo real. Having to render this amount of data definitely has its own hurdles that we had to work around. We had to create a very specific tree shader so that we got the same look as our tree references and have the light interaction that we needed to get the photo real quality that Marc and Volker so wanted. Spending the time and creating this shader early on was the key to getting the shots to look so good. Prime Focus gave us some of the people assets, each of which needed extensive work to get them integrated in our pipeline and renderer 3Delight.

Mark Wendell – CG Supervisor // The amount of data shared from Method Studios in particular was huge. The nice thing about the data sharing, though, was that they gave us everything, including not only the final tree models and textures, but all the SpeedTree scene files used to generate those models. That gave us the flexibility to adjust things like wind parameters and geometric details specifically for our shots. This was important for us, since most of our shots were on the south lawn of the White House, while most of Method’s shots were at other locations, so they never needed to add the detail to the south lawn trees that we required. By having the original scene files, we had everything we needed to ‘detail up’ for our shots fairly quickly.

We learned a lot about raytracing massive amounts of geometry on this show, taking advantage of instancing, and using a fairly simple shading model. One of our shading TDs, Daniel Dresser, came up with a nice way to add color variation to tree instances across the parklands at render time, and then any further variation was managed in comp since we provided them with unique hue-based ID mattes for each tree.


Can you tell us more about their animation and the renders?
Martyn Culpitt – Visual Effects Supervisor // We used Houdini to create the smoke passes needed for each of our shots. Some of the shots had over 10 different sims to make sure we had the right movement and feel for each element. Some of these would take many hours to render as there was so much detail needed, especially in the close up shots around the balcony of the White House and the windows. It is very hard to create such subtle detail in the smoke, it took us a lot of time and iterations to get the exact feel we wanted. Then we had to use the many passes and AOV’s to get the final look. For the fire we used elements that we had shot and these were comped in.

How did you get your references for the White House?
Martyn Culpitt – Visual Effects Supervisor // Marc and Volker had done extensive work in capturing as much of the White House and Environment as they could. They filmed both from the air and on the ground but there we specific limitations of the area, as it is obviously very protected. So some of the references and textures we had to do quite a bit of paintwork and clean up on to use them for our shots.


Can you tell us more about the crowd creation?
Martyn Culpitt – Visual Effects Supervisor // Prime Focus sent us their assets for the National Guard, Police, civilians and reporters. We spent a lot of time tweaking for our rigging, pipeline and renderer 3Delight. We also created many props and different little pieces for each person to be different. In some of our biggest shots we had over 6000 people, this was itself an issue that we had to figure out when it came to rendering. Using our internal layout system helped us to be able to do this.
We created a rig right at the start so that it could be easily ported over to each different type of person and be adjusted so it would work efficiently. We used our own internal layout system to create the actual crowds and to give us the randomness that we needed. We created a way to apply many different items of clothing, skin color, props etc to give the crowd variation and to adjust where needed. We are able to save a lot of time accessing only a small part of the crowd and tweaking it with out having to adjust the whole crowd at once.

All the motion was applied using ‘motion capture’ that was adjusted and tweaked as needed. Most of it was supplied from Uncharted Territory. But there were cases where our animators would hand animate the crowd so that we got the motion we wanted.

We used Houdini to create the smoke passes needed for each of our shots. Some of the shots had over 10 different sims to make sure we had the right movement and feel for each element. Some of these would take many hours to render as there was so much detail needed, especially in the close up shots around the balcony of the White House and the windows. It is very hard to create such subtle detail in the smoke, it took us a lot of time and iterations to get the exact feel we wanted. Then we had to use the many passes and AOV’s to get the final look. For the fire we used elements that we had shot and these were comped in.


Can you explain more about the crowd animation?
Mark Wendell – CG Supervisor // We decided to take an interesting mix of old-school/new-school to our crowd animation. We used a fairly manual approach to constructing clusters of characters, using a variety of in-house and client-supplied mocap cycles. Once these clusters were built, we expanded the crowd to thousands by using these clusters as building blocks. We broke up any repeats of these clusters by applying random time offsets, choosing procedurally among alternate geometry and texture sets, and manually editing any offending characters. On the render side, lighters had tools to globally assign variations in geometry and textures, or select and alter just one character at a time. Since the bulk of our crowd shots mostly involved ‘idle’ motions, this manual approach proved much faster and more flexible to set up and edit than engineering a procedural approach to the animation from the start.


What was the biggest challenge on this project and how did you achieve it?
Martyn Culpitt – Visual Effects Supervisor // The biggest challenges we had were creating such a large crowd and having to render it with our full Environment. The other headache we had was having to create two versions of the White House, one damaged and one pristine. The crowds had their own unique issues that we have now solved after this movie. A lot of it had to deal with so many individual people so we created tools to access individuals or selected pockets without having to open the entire crowd system. It made huge differences both for workflow and also when it comes to render time.

The White House was the hardest asset to create and work with as we had two versions of it in the pipeline at one time. We created the pristine version and then had to destroy/damage it piece by piece. This was done in both the asset and also using matte painting work to fully destroy it. The issue is that the pieces we destroyed were also linked to the pristine version so we had to be very careful not to break the links between each and keep them separate.


Was there a shot or a sequence that prevented you from sleep?
Martyn Culpitt – Visual Effects Supervisor // Mainly the Crowds and the Trees, but once we figured out the shaders and the way we could handle that many people then I was finally able to take a deep breath.

What do you keep from this experience?
Martyn Culpitt – Visual Effects Supervisor // Working with Uncharted Territory, especially Marc, Volker, Julia and Roland was a fantastic experience and would love to do it again. We worked well together and I think we were able to achieve some fantastic work.

Mark Wendell – CG Supervisor // This show gave us the confidence to commit one hundred percent to physically plausible ray-traced shading, as the advantages both in terms of visual realism as well as lighter time really paid off on this film. Also, based on our experience with building large environments on films like White House Down and Elysium, we’ve invested development effort into expanding our toolset for setting up and rendering complex environments. While the parklands in WHD had hundreds of trees and took a bit of effort to get final renders through, we can now render tens of thousands of trees, in a fraction of the memory and render time of previous shows, using our updated tools.
 
What are the four movies that gave you the passion for cinema?
Martyn Culpitt – Visual Effects Supervisor //
BLADE RUNNER
ALIEN
THE MATRIX
STAR WARS / THE EMPIRE STRIKES BACK

Mark Wendell – CG Supervisor // For me, it was really just one film… 2001: A Space ODYSSEY. It created an incredibly realistic future in space, and made me aware of how important research and thoughtful art direction are when it comes to science fiction. I had the chance to discuss and screen the film with Doug Trumbull recently, and that was one of my childhood dreams realized. I still study the docking sequence to this day for the amazing composition and shot design. Beautiful work.

A big thanks for your time.

// WANT TO KNOW MORE?

WHITE HOUSE DOWN: Dedicated page about WHITE HOUSE DOWN on Image Engine website.





© Vincent Frei – The Art of VFX – 2013

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