VFXTalk Meets The VFX Masters Behind The Magic of Harry Potter 4

[Oracle]

<a href="http://www.vfxtalk.com/forum/showthread.php?t=6820" target="_self"><img src="http://www.vfxtalk.com/newsimages/harry_potter_4_thumb.jpg" align=left border=0 width="160" height="90"></a>You have been very patient VFXTalkers, but your wait if finally over. Here are the answers to your questions for the VFX Masters at Framestore CFC regarding their incredible work on Harry Potter and The Goblet of Fire. They have given us oodles of images for you to feast your eyes and more importantly...knowledge, so wait no more and read on.

[Oracle]

You have been very patient VFXTalkers, but your wait if finally over. Here are the answers to your questions for the VFX Masters at Framestore CFC regarding their incredible work on Harry Potter and The Goblet of Fire. They have given us oodles of images for you to feast your eyes and more importantly...knowledge, so wait no more and read on.

About Harry Potter and The Goblet of Fire
Harry's fourth summer and the following year at Hogwarts are marked by the Quidditch World Cup and the Triwizard Tournament, in which student representatives from three different wizarding schools compete in a series of increasingly challenging contests. However, Voldemort's Death Eaters are gaining strength and even creating the Dark Mark giving evidence that the Dark Lord is ready to rise again. In the unsuspecting lives of the young wizard and witches at Hogwarts the competitors are selected by the goblet of fire, which this year makes a very surprising announcement: Hogwarts will have two representatives in the tournament, including Harry Potter! Will Harry be able to rise to the challenge for the Tri Wizard Tournament while keeping up with school or will the challenges along with Voldemort's rebirth be too much for the young hero?

To see the trailer, click here



About Framestore CFC
Framestore CFC is the largest visual effects and computer animation studio in Europe, with over 20 years of experience in digital film and video technology. The company has won numerous international awards including two Technical Academy Awards from the Academy of Motion Picture Arts and Sciences, three BAFTA Craft Awards and eleven Primetime Emmy Awards.

Framestore CFC Website:
http://www.framestorecfc.com



About Ivan Moran, Compositing Supervisor
With over twelve years experience in visual effects, Ivan Moran has held senior level roles in both 2D and 3D. Having studied photography, maths and science, Ivan has used a versatile blend of skills to work in traditionally diverse areas of the industry.

From 3D Artist at a leading broadcast design studio in Sydney, to Lead Compositor for feature films in Australia, New Zealand and London, Ivan has VFX experience encompassing broadcast design, TV commercials, feature films, and on-set supervision.

As Compositing Supervisor at Framestore CFC, Ivan developed many of the 2D tools used for compositing the underwater sequence on Harry Potter and the Goblet of Fire. He continues to work on high profile feature projects at Framestore CFC. His previous credits include, Children of Men (2006), X-Men3 (2006), Beyond the Sea (2004), Alien vs Predator (2004), Harry Potter and the Prisoner of Azkaban (2004), The Lord of the Rings: The Return of the King (2003), The Matrix Reloaded (2002), Ghost Ship (2002), Rabbit-Proof Fence (2002), Charlotte Gray (2001) and The Lord of the Rings: The Fellowship of the Ring (2001)




About Rob Allman, Senior TD
Rob Allman joined the Mill in 1998, having graduated with a distinction in Computer Animation (MA) and a BA in Fine Art. In addition to his film work, he has also worked in commercials, and spent time working on set for the Harry Potter production, Prisoner of Azkaban. At Framestore CFC he continues to specialise in shading and lighting, and continues to work on the Harry Potter series. His previous credits include, Harry Potter and the Prisoner of Azkaban (2004),
Harry Potter and the Chamber of Secrets (2002), Hannibal (2001), Harry Potter and the Philosopher’s Stone (2001), Tomb Raider (2001), Band of Brothers (2000), Gladiator (1999) and Babe2: Pig in the City (1998).




About Tim Webber, Director of Visual Effects
Since joining FrameStore in 1988 as a graduate trainee with an outstanding academic record in Maths, Physics and Art, Tim Webber has been responsible for pushing the boundaries of digital imaging in the world of film and television. He has been involved in developing a number of groundbreaking new techniques, including Framestore CFC’s virtual camera and the M-Rig system. Tim became a Partner at FrameStore in 1992. Starting with 2nd Unit directing on Merlin, Tim went on to direct commercials and other shorter projects as well as supervising VFX work. As Director of Visual Effects at Framestore CFC Tim has been helping with the expansion of the company over the last few years. His previous credits include, Children of Men (2006),Harry Potter and the Goblet of Fire (2005), Lassie (2005), The Libertine (2004), Enduring Love (2004), Dinotopia (2002), Shackleton (2002), Mansfield Park (1999), Notting Hill (1999), Merlin (1998/II), Lawn Dogs (1997), A Life Less Ordinary (1997), FairyTale: A True Story (1997) and Gulliver's Travels (1996)




Now you know who they are, let's hear their answers to your questions...


What software was used for the underwater sequences?
TW: Maya, and Shake were the main appliczations. We also used a little houdini for special bits and pieces, Boujou and MatchMover for tracking, Z-brush for some modellijg tweaks, furnace shake plugins and various bits of in house software


How long did it take to render these shots?

TW: It varied hugely. We rendered environments and creatures separately and often hero creatures separate from background creatures. Some backgrounds were highly complex with lots of rock detail and thousands of plants that needed their motion to be solved. Similarly some of the mermaids took a long time thanks to the complex lighting model which gave them their translucent and pearlescent look. In particularr the hair took a while to render. For example some particularly tricky mermaid renders might be up to 16 hours a frame but most elements would be a good deal quicker.




Did you use special software to create the hair on the mermaid?

TW: The movement was created with Maya hairs and Maya dynamics. We then used some in-house tools to create the volume and add a little more subtle movement. Controlling the movement and keeping the hair looking attractive was hard because the mermaids swam very fast which tended to flatten the hair down onto the scalp. So each shot had it's own tricks and techniques applied to control the hair style.
A lot of work went into shader writing to create the translucent sea-anenome look which was incredibly complex to achive. (much more so than we expected!)

Did you need to use special water simulation software such as RealFlow or was it all done using built in 3d tools?

TW: We avoided using full simulation for the movement of the elements underwater. This was mostly done using an in-house hair system and built in tools (Maya dynamics etc.) for the plant movement in the water. Syflex Cloth was used for the cloth to give it and we managd to get some good underwater mo ment out of this.
The water surface was simulated using in house software.



What types of techniques did you develop to integrate better live action with a virtual sub-aquatic ambient?

TW: We studied the effects on a n image of underwater camera housings quite closely. There are actually two types of underwater camera housing - flat port and domed port. Our live action material was shot with a domed port, so we matched the effects of these but we also added a little of the effects of a flat port (like chromatic aberration) to add to the underwater feel.

We ensured we kept our CG cameras "bouyant" and had plenty of "grunge" floating around in the water with lots of diffusion on distant objects.

What kind of research did you do in order to get the look and feel of a underwater lake to look just like a underwater lake? I notice that the ropes and rocks are all properly covered in moss and the entire look and feel is properly murky...

TW: We looked at a lot of reference photos of underwater scenes and spent a long time developing procedural techniques to cover objects. We had a number of different affects that were procedural but that we could control with painted maps - short moss, long moss, various small plants and ocassionally we added barnacles into texture and displacment maps.

One of our big problems however was that most real underwater shots had a visiblity of only a few metres at the most. Some of our shots reuired us to see hundreds of meters to effect the story telling.



What software was used to create the underground terrain? Was it just modelled in your 3d tool of choice or did you use in house tools for the terrain generation?

RA: 1. Maya and Renderman. 2. It was my 3d tool of choice and no in house tools were used.

How did you color correct the scene - was this done in post after compositing to make sure the characters and the cg all blended together seamlessly with the right shades of green?

TW: Most of the colour correction was done suring the compositing stage. However we then did a few tweaks on the final compsoite using baselight (our Dig ital grading tool), particularly to make sure all the shots had consistent colours.




How was the interaction between Harry and the Grindylow's in the dunk tank planned and executed to make it easier for the animators and the compositors/roto people? How did you plan the necessary specifics for render passes?

TW: On the shoot we had divers grabbing Harry to simulate the affect of Grindylows. This was kept fairly loose in that we had not choreographed exact grindylow movement interacting with Harry. However as the editing at this stage was failry quick this was not neccessary and all the timings were worked out by making the animation fit to the live action.




How much of the actual Harry was shot in the underwater blue-screen setup?

TW: About two thirds. The wider shots and one or two close up moments which were uinachievable in a tank were done in CG.



What tasks and objectives where the compositors given? Did they only receive CG elements, or did they have to incorporate 2D elements into the underwater sequences? Items like flotsam, debris, etc.

TW: Virtually all CG elements but there was the occasional 2d element used. (e.g. a few of the bubbles - but not very many)

Was there a lot of crossover between compositors while working on this sequence?


IM: Initially one compositor would be compositing an environment while another would do the creature. However, the compositors loved working on their shots and wanted to own everything so there ended up being not much crossover at all!

Was there any trouble in communicating the look of the shots between the compositors and the Technical Directors?

TW: This is always a critical part of the process and it was and area where we worked hard to ensure informaiton flowed smoothly. As always things statred off not so good and improved as the team gets used to working together.


Were there any new 2D tools written for the compositing application (Shake?), that helped the compositors tweek the CG elements to better fit with the live action?

IM: A lot of the shading normally done in 3d was done in the compositing pipeline which gave our compositors much more freedom to adjust lighting to help integrate the cg. As well as that, we developed some tools to deal with the optical qualities of shooting underwater, such as chromatic aberration and lens warping effects.




In many shots there was camera movement, was it difficult for the match movers to lock onto the camera move, and how were the problems overcome?

TW: Yes very difficult! Ther were no clever techniques to overcome the problems; mostly hard work. We aere also lucky that underwater scenes are very forgiving of not 100% accurate tracking.


How much of the shot background's were done with 2D matte paintings vs. all 3D created environments? Or was it a combination between 2D and 3D (2 1/2D camera projection approach?)

TW: Many backgrounds had at least some 2d or 2.5d elemetns in them. However because fo the large amount of moving plants that covered the rocks we were not able to use as much as we would have liked.




On a project like Harry Potter, how much RnD does Framestore-CFC do? Do you mainly make use of off-the-shelf tools or do you develop a lot of your own (in terms of both 2D and 3D)?

TW: I would say about 10-20% is in house tools. But many of these are not stand alone but integrate closely with off the shelf software.

How many last minute tweaks went into adjusting the water/fluid distortion. Given the amount of cg renders, did you get it right all the time, or were there last minute tweaks?

IM: We had in-house tools developed to apply correct lens warping depending on the focal length of the shot lens. Shot specific tweaking was done as well but not very often.



Were there any wire removal shots, and did you use any plugins to remove them?

IM: There wasn't wire removal per se but we did have to remove a lot of tracking markers and rig from the pool the actors were shot in. No plugins as such were used for this though.

What was by the far the biggest challenge in term of visual effects in this movie, and how did you overcome them? Was there a different treatment? A new techique? Which sequence was the hardest to work on, and why?

IM: The underwater sequence was incredibly challenging, particularly when you look at the plates we started with: actors on bluescreen. It was quite daunting and challenging to have to create a believable cg environment and populate it with cg creatures. There have been some films before that have looked at underwater effects but nothing quite on the scale of this!

RA: For me dealing with ultra craggy rocks and dealing with so much of them (rendering occlusion on heavily displaced objects) and meeting the clients brief regarding the look. Also achieving the look on the Mermaids. Such liberal use of subsurface scatter was new for me.




What sort of freedom were you given in creating the looks for the sequences you were in charge of?

IM: We had artwork and creature maquettes to base our look from but these were style guides in essence. Because we were creating so much of the picture we had quite a lot of freedom to experiment with looks for the creatures and environment.

RA: The usual; I would start the process and then take on input from supervisors.






How many artists did you lead and did you get a pick of the sequences or are they assigned based on your strengths?

IM: The underwater comp team was about 15 strong and shots were assigned on the strengths of the individual compositor

RA: About eight? I worked on a smaller number of the more difficult shots.




What other talents make up a good compositor? What other skills should they be fluent in? Photography? Color theory?


IM: Compositing combines both technical and artistic talents which is quite a unique blend when you look at other professions. Any sort of training that helps train the eye is essential, such as photography or fine art. As well as this it is inevitable you will have to deal with the technical aspects of colour theory so training in this is essential. Out of the two talents, acquiring an eye for a balanced great-looking picture is the key and this can be inate or take years of training to perfect.

RA: Increasingly a good understanding of 3d!


When did you decide to start in the visual effects field? After high school, college, or earlier?

IM: During high school really. Unfortunately for me I was way too early and there were no school or college subjects anywhere in the world that were vfx specific. Believe me, I looked!

RA: Four years after art college




How much has the line between comping and 3D blurred for you? As a lead do you have more control on what the 3d department gives you?

IM: There are still definitive parts of the process that are most definitely either 3d or 2d. The lighting stage of things is a bit blurred now though, particularly with the way we do creature work at Framestore. The 3d TDs need to be much more proficient at knowing what happens at the comp stage and conversely the compositors need to know much more about shading and lighting than they ever did before.

RA: Somewhat; perhaps only because some of the precomping stages could/should have been done in the shaders.


What was the most challenging shot to do, and why?

IM: The closeup shot of the mernaid was the most challenging in terms of fine detail and extreme depth-of-field but overall the wide environment shots with CG Harry were probably the most difficult and time-consuming.

When your team is faced with the challenge of creating a certain effects shot/scene...what are the typical work patterns you follow? And is the final result always as you originally envisioned it, or does the process often change and adapt as new ideas or challenges arise?

IM: The look is developed in 3d and 2d concurrently but it is a very fluid process that is constantly changing as new improvements are made. The bar is set higher than any of us can jump straight away though but that's part of the challenge, you always to create something no-one has done before.

RA: Modelling and rigging are done pretty much in isolation, for a TD like me. Texturing and shading are more closely bound. Final rendering to some extent dictates the method (without final output there is no shot). There is not much in the way of happy accidents (accidents are invariably of the disastrous variety). Pretty much the success or failure of a task can be measured by the difference between it and the original concept.



What was unique about working on this picture that sets it aside from other film work?

IM: Creating an entire environment that a lot of people took for granted was probably the biggest complement we could hope for. A lot of people assumed we shot the scene underwater in a murky lake and added some cg creatures. Not quite!

RA: The total immersion in the enviroment.

What resolution were you working at?

RA: 2048x1280

Finally, because I know how busy you all are, which FX shot did you feel ended up looking better than you had ever anticipated, and why?

IM: I think any of the wide environment shots were particularly impressive, they look totally real which wasn't easy to do!

RA: Harry discovers the abyss. Too big and difficult to do, but actually worked really well. Great study in scale, minute inspection of a foreground inches away at the beginning of the shot, gives way to huge panorama of the chasm, with digital Harry hanging against it. And the CG (more-or-less) held up.



From all the VFXTalkers, thank you very much.

Written by VFXTalk

[skinnie buddah]

I was wondering when the answers were coming. This is awesome. Great article.

Thanks Framestore and as always thanks Oracle

[muffycompo]

This is a great interview!

[sreedhars79]

mind blowing job...

[Vfx Gal]

Thanks a lot to all those who made this Interview available to us vfx talkers.Very Informative article.

[shayju vallattara]

What is the position of Combustion and After Effect in VFX(compositing)?
and what plugins use in Dynamic Efect.
and How can apply under water scene?
plz rly'

[vaseem]

wOw gReat interview... thank u 4 thE VFX Masters Behind The Magic of Harry Potter 4

[tritrinh]

May I say Ema Watson look quite atractive...

[AVTPro]

This is one the hottest scene out of all his movies. Love it.

[godzila]

I like Harry Potter and The Goblet of Fire movie because there are so many characters in this movie with outsiders come to play contest & it was harry potter who was really do great job in each competition. You posted very nice photos of harry potter of this movie. I loved all the scenes. Thanks

[asif ali]

wow...

[Martys]