POMPEII: Chris MacLean – CG Supervisor – Mr. X

Chris MacLean has joined the team of Mr. X in 2010. He has participated in many RESIDENT EVIL, THE THING or CARRIE. This is his fourth film with director Paul W.S. Anderson.

What is your background?
I come from a traditional arts background. I started working as a graphic designer in 2001 and in 2008 made the move to CG. I worked on a few documentaries for Myth Merchant Films in Edmonton before coming to Mr. X Inc. I started as an Asset Artist and am now into my fifth year with the company.

What was your feeling about this fourth collaboration with director Paul W.S. Anderson?
Paul is a very visual director and this makes him very easy to work with. I can honestly say that I was excited to be a part of this film and to work with Paul again. He is a very positive person and that tends to rub off during production. Knowing how hard Paul and the production team worked to get Pompeii off the ground was also a great motivator.

What was his approach to the visual effects?
Paul loves spectacle. There seems to be a trend of going bigger and better with the VFX on every Paul movie we do. POMPEII was no exception. Dennis and Mr. X have a great relationship with Paul so there is a level of trust there that makes for a creative and rewarding experience on our end.

What was your role on this show?
I was the CG Supervisor. I spent the first 3 months of production on set with the previz and concept team. I then came back to the studio to begin shot production. My first few weeks were very much about logistics and planning as the visual effects were very ambitious given the compressed timeline. Once we were in full swing I spent my time helping the artists and the DFX Supervisors problem solve. If there was any time left over it was spent in dailies or helping with shots.

How did you collaborate with Production VFX Supervisor Dennis Berardi?
I worked with Dennis on set during pre-production through the concept and previz stage. We had a lot of work to do in terms of making technical and creative decisions before the shoot. Once the shoot started I headed back to the studio to prep the teams and help get the sequences ready. Once Dennis and I were both back in the studio we took a divide and conquer approach.

Can you describe one of your typical day’s on-set and then in post?
On set I worked with a small team of exceptional artists. Our days were spent animating shots and cutting together sequences. We spent a lot of time going back and forth with the Production Design and Prop teams as well. We helped flesh out some of the city designs, like the harbour area of the city. We worked through the stages of the Vesuvius eruption and created some great concept frames that we used as reference for the big finale. Paul was there for most of pre-production so he got to see our progress and we had great feedback early on. It really helped us get a leg up back at the studio; we were able to start assets much earlier than we had on previous projects. Once the shoot started I didn’t spend much time on set but did go back for a few of the surveys and shoots.

Post was all about shot production. With the aggressive time line we had to get as much started in parallel as possible. In the beginning my “typical day” was spent with department heads going through the previs and talking through methodology. Towards the middle and end of post my days were spent problem solving with the artists and communicating direction or notes from Dennis and Paul.

How did you approach the previz creation process?
The first few weeks were spent getting the previz assets ready. We did some very early conceptual fly throughs of the environment to give us an idea of the scale we would be working with. There were also quite a few character and prop rigs to get ready for the action sequences. For most of the previz we had great storyboards to work from. Paul spent quite a bit of time with the storyboard artists getting these locked down. Our mandate was to translate these into editable shots and to respect the spirit of the boards. Our previz editor would then cut and score the sequences. We ended up with some really great sequences and the team did an excellent job with the translation.
We also did technical previz which became invaluable for designing the green screen set for the horse and chariot sequences as well as some of the more complex Amphitheatre shots.

What were the real size of the sets?
The Production Design team did a really great job with these and they were diligent in designing them to keep the VFX extensions as seamless as possible. For the final act of the movie we had CG versions built for almost all of the sets so we could destroy them.

The Pompeii street set was about 200 feet long. There was sidewalk on both sides but we only had buildings on one. It was a great set though; very modular and parts of it could be moved or changed to create different areas of the city. The market stalls and set dressing was all great reference we used for creating our own CG props.

The Amphitheatre set was built to scale and the arena area matches the dimensions of what is still there today. For the stands we had a long side pie section which included the first section of seats and the imperial box. The set was redressed many times and shot from different angles so it could play as either side of the Amphitheatre. There were very few shots that didn’t require some form of CG extension but with the way the set was designed it was fairly easy to seam up with the digital asset.

The Forum set was a little over half of the Temple of Jupiter and a lower section of the Macellum. This was perhaps one of the most CG intensive set recreations as the final leg of the chariot chase takes place here and we cover the whole Forum from front to back while destroying it with lava bombs.

The Villa was another great set. The interior was entirely practical in the first half of the movie with the exterior being done in CG. During the eruption we completely destroy the Villa and we created sections of the interior in CG to match into the CG exterior.

The Horse Track was 300 feet of green screen with a dirt track for the chariots and horses to run on. There were a few horse shots done on location but for the most part if you see a horse in Pompeii it was shot on the green screen set. This meant we were tasked with creating the CG environment around it.

Can you tell us in details about the creation of the city of Pompeii?
We had originally wanted to build the city once and iterate on levels of detail as needed. We started working on this around the same time as pre-production began but we soon realized that given milestones such as teasers and trailers this would not be possible. So in order to create the many high quality hero environment assets we needed we took a more localized approach. We built hero versions of the Forum, the Villa and Amphitheatre first, as these were going to be featured early on and then worked our way out.

The CG Pompeii street build was modular and we ended treating it much in the same way the practical set was. We built a catalog of complete buildings, Wall modules, streets and props that we then placed based on our original layout of the city. This was always done based on the practical camera or geographic location of the action. These buildings ended up working for our street and mid-range aerial shots. Our full city asset was used in the wides and was much lighter than the hero buildings.

Did you received specific indications or references from the director?
Paul gave us many books and a few documentaries about Pompeii. Paul Austerbury, the Production Designer, was also a great resource for reference material. He had a large collection of obscure books and reference. Some of the best reference we had was from the city itself. Dennis did a heli shoot in Pompeii as well as a ground level survey. This combined with artist renderings of what was there in 79AD gave us a great starting point.

How have you handled so many set extensions and environments?
Being involved in pre-production helped us with an early start here. We had access to the set drawings as soon as the ink was dry. We also had access to the sets as they were being built which helped us develop the textures and lookdev. With these on the floor early the layout artists, tracking artists and animators were able to iterate quickly using the modular buildings and props. We were able to reuse layouts, doing them in city sections so they could cover multiple shots.
To add visual interest we did some texture/matte painting paint overs and projections. The wide aerial shots benefited most from this technique.
The volume was a bit daunting and we did the majority of the layouts and assets at Mr. X but we had some great vendors to help us with volume.

How did you populate the city and the various places?
We had a very extensive asset library for POMPEII. Hundreds of props, trees, and vegetation variations were built. We had clean and destroyed versions for all of them. We had everything from fish-drying racks to market stalls to zucchini baskets. The asset team did a tremendous job getting through the volume we needed to build to populate the city.

For the crowds we used Massive. We did some custom animation for this but most of the crowd were done with mocap. We did a session down at Giant Studios in LA where we captured the audience movement for the gladiator battles. We got a lot of the running, reactions and tripping for the eruption from this session as well. The animators then broke these into takes that Massive were fed into the Massive Engine.

What was the most challenging building or environment to create and why?
Mount Vesuvius is the first environment asset that comes to mind. We went through three iterations and had the pre- and post-eruption versions to contend with.

The most challenging building would have to be the Forum. We scraped the ground with the camera a few times here and it was a massive area to cover in CG.

How did you manage the various destructions and explosions?
The FX team used Houdini to tackle this. All of the building and prop assets were modeled with destruction compliance in mind. The destruction itself was done with our own flavour of Bullet and a combination of Voronoi and custom fracturing tools. The explosions, smoke and fire were all handled with Pyro in Houdini.

Let’s talk about the volcano. Can you explain in details about its creation?
As I stated above Vesuvius was one of the most difficult environment assets to build. Selling the scale was one of our biggest challenges. Early on we had decided to be as historically accurate as possible. Vesuvius, in 79AD was twice as high as it is today. When it erupted it blew its top; reducing its altitude and expanding its crater. The event was very similar to what happened to Mount St. Helens in 1980.

For its final pre-eruption iteration we meshed DEM data of Vesuvius and then sculpted the extra height in Mudbox. We already had many of the cameras done for the mountain shots so we were able to sculpt detail where needed based on the shot requirements. For the cone shots we extracted the summit from the full sculpt and added extra subdivisions. This allowed us to get extra detail into the sculpt for Vesuvius’ “close-ups.” We painted 80 4k texture tiles in Mari which covered us for the level of detail needed. Lookdev and tree placement was done in Houdini with Mantra. We used point instancing and the tree library to populate the mountain with vegetation. We controlled the vegetation density, type, direction, scale and rotation with the point attributes. We ended up creating LODs for each tree variation to economize on render times for wider renders of the mountain.

The post-eruption version of Vesuvius was only used after the pyroclastic eruption. For this we sculpted the crater to match as closely as possible to Vesuvius’ modern shape and did a new point layout for the vegetation.

How did you create its big and various eruptions?
For the plume we used multiple instanced Pyro containers to get the resolution needed for these massive events. For the lava bombs the FX artists also used Pyro but clustered the containers to create the trails. The lava rivulets were handled with Houdini’s L System. The plume lightning was also done with the L System. The FX were all rendered in Mantra, so we had to mesh out the FX for many of the shots for proper lighting and shadow translation into our Maya/V-Ray pipeline. For some of the Vesuvius centric shots the lighters used Mantra as it was more economical and allowed for a more direct lighting solution.

Can you tell us more about the big final eruption with the pyroclastic flow?
We used the same bullet/fracture system as we did for the buildings for the Vesuvius destruction. For the plume and the pyroclastic flow we used Houdini Pyro. We used the same Pyro multi container setup as many of the other shots but used point advection to give the pyro it’s glow. For the tree destruction we used DMM.

All of the timing for the flow was done by the animation department in post vis which gave the FX artists a great starting point as it is very time consuming to iterate on simulations of this size.

How did you handle so many FX elements?
Planning, organization and great FX artists. We broke the shots down into their finite parts and tasked them accordingly. By the time we were ready to start shot production the FX department had their tools ready for the major FX types needed for the film. The FX artists at Mr. X are also very good at data management. They take great pride in keeping their sims under control in a production environment. For some of the larger pyroclastic shots we did use 64 gig blades, but for the most part, with some creative organization, we were able to keep everything on 32 gigs.


Can you tell us more about the tsunami creation?
We did the previz, initial assets and layouts for this sequence but the credit goes to Scanline for making the tsunami shots what they are. They used their proprietary Flowline software.

The final sequence puts the actors in the center of the Pompeii destruction. Can you explain in details about your work on this final part?
The majority of the chariot chase sequence was shot on the green screen horse track with the stunt doubles. The actor close-ups were then shot on the Pompeii Street set or on green screen. Almost every shot in this sequence had a CG background and all of the riding shots needed face replacements.

Can you tell us more about the creation of the digital doubles?
Our character pipeline is very streamlined. We start with the scans and photo surveys from set. For POMPEII we did all of our leads along with 20 extras for the crowds. We have a “Mr. X” base topology we use for most of our characters. The textures are painted in Mari from the photo surveys and our lookdev is done in V-Ray. This didn’t change much for POMPEII. We did asset variation for the crowds to populate the Amphitheatre for the Gladiator battle and the city for the medium/wide shots.

How were created the corpses with the ashes?
These shots were done by the Mr. X Gotham team in New York. They had great reference of the plaster casts from the bodies from Pompeii. They designed the whole sequence and did a great job executing it.


What was the biggest challenge on this project and how did you achieve it?
The biggest challenge on POMPEII was time management. With the tight schedule there was little time for error and very little time for iterations or creative process. This meant we needed to be fast on our feet and make the “right” decisions. We took the time we had and designed the shot methodology around it. The production management team also did a great job keeping us all in line and on time.

Was there a shot or a sequence that prevented you from sleep?
The opening aerial shots of Londinium. We did those two shots in five weeks from asset build to comp.

What do you keep from this experience?
You’d be amazed what you can do when you stop worrying about how long it’s going to take and get down to business.

How long have you worked on this film?
We started pre-production in January of 2013 and we finished in January of 2014.

How many shots have you done?
On POMPEII? A handful, maybe four or five. In my career… 210 and a half? I don’t know, I don’t really keep track of that sort of thing.

What was the size of your team?
At any given time there were about 130 artists working on POMPEII. This does not include our outsource partners.

What is your next project?
CRIMSON PEAK.

What are the four movies that gave you the passion for cinema?
2001: A SPACE ODYSSEY
APOCALYPSE NOW
JAWS
MONTY PYTHON AND THE HOLY GRAIL

A big thanks for your time.

// WANT TO KNOW MORE?

Mr. X: Official website of Mr.X.





© Vincent Frei – The Art of VFX – 2014

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Vincent Frei

Founder & Editor-in-Chief // VES Member // Former comp artist

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