What is your background?
I began my career as a camera assistant and editor. I joined Cinesite in 2004 and have been involved in many of their high-profile projects including GENERATION KILL, for which we won an Emmy Award for Outstanding Achievement in Special Visual Effects. I also led Cinesite’s key sequence on THE GOLDEN COMPASS where lead characters Lyra and Mrs Coulter travel to London in a computer generated air balloon, surrounded by a stunning panorama of London. In recent years I’ve been heavily involved in Cinesite’s work on the HARRY POTTER series and supervising our 2D work on the films.
How was your collaboration with Tim Burke, the production VFX supervisor?
Tim and I have worked together for a number of years now, since HP6 (HALF BLOOD PRINCE) and have developed a very strong working relationship. Tim has a good sense of what David Yates is looking for in his visual effects sequences and is always keen to provide us with as much insight into what David would expect of a shot, so we can direct the efforts of our teams effectively and efficiently.
What are the sequences made by Cinesite on this movie?
We were tasked with creating Lord Voldemort’s snake-like nose, the ghost of Dumbledore, a Patronus doe and the wreath of Christmas roses conjured by Hermione at Harry’s parents’ grave. We also rebuilt the set for Godric’s Hallow in CG; as well as 2D and CG set extensions, full CG environments and CG snow in this scene. And we additionally created the environments for the Windswept Hill sequence, which involved shooting terrain photographs of Malham Cove in Yorkshire and compositing them into the digital scene.
Did you used some footages of Sir Michael Gambon for the ghost of Dumbledore?
Yes, Sir Michael Gambon was shot in front of a green screen for the corridor scene, which we used as the basis for our effects.
Did the length of the Patronus doe shots caused you worry?
We didn’t have a problem with the length of the shot, but we did have to work on the shot for over a year as the Director’s vision changed as the shots evolved.
How did you get involved in compositing on the aspect of the Patronus doe and its particles?
The background plates were shot with a live action dog wearing a blue LED light suit, which walked the path that the doe would travel, so we got all the interactive lighting on the ground and the branches in camera. The fully groomed CG doe, along with the many 3D fluid effects passes, were combined in Nuke and then blended off and diffused, in many places almost completely transparent, especially along the back edges. This sense of transparency gave the ethereal impression of the doe not being entirely in our world. We also created smoke in Nuke which cascaded off and around the doe to help this ethereal look.
Did you use the 3D capabilities of Nuke? And on what sequences?
Nuke’s 3D capabilities were heavily used across all sequences and shots on this film. Tracking is increasingly a regular part of the pipeline process so we use Nuke’s 3D capabilities for tracking as much as we can. In particular, on Voldemort’s nose, being able to unwrap the CG and Live action heads for more precise paintwork on a flat texture was very useful. The Godric’s Hollow digital environment extensions benefitted from Nuke’s 3D capabilities as we were more accurately able to place objects in the correct depth. In the Windswept Hill scene, we were able to visually judge the camera’s position across multiple shots to more realistically position a background panorama and make the scene continuity work.
What was the real size of set for the Windswept Hill sequence? How did you expanded this landscape?
The real size of the set was around 30 by 30 feet. The full CG environment in the establishing shot of Windswept Hill was built from a set of HDRI texture photography and photogrammetry taken on location in Malham Cove in Yorkshire. Working with the client, we developed some detailed pre-vis so that we could prepare to shoot our stills and production could approximate the camera move to shoot a live-action element of Harry and Hermione.
We took stills at ground level and augmented them with photos taken from a helicopter. We then used our proprietary photo-modelling software to reconstruct the geometry and projection cameras for this environment. The same technique was used to extend the top of the cliff using modelled cliff rocks. We also used the same set of stills to generate a digital matte painting of the sky and were then able to composite Harry and Hermione back into our full CG shot.
For the balance of this scene we used the same set of stills and Nuke was used to create post-vis views of each key angle with 16K stitched HDRI panoramas projected onto spheres. Using the tracked cameras oriented to the practical set, we were able to interactively position every shot’s camera in real time to help orchestrate the background continuity of the scene. For areas of the practical set needing extension, digital matte painting extensions were created using reference textures and then projected onto displaced planes in Nuke which lined up with the practical set seamlessly. Green screen keys were particularly difficult due to the bright nature of the background skies vs. the comparatively dark colour of the green screen.
Have you developed specific tools to help you in compositing?
Nothing developed specifically for Harry Potter. Potter was one of the first projects to exclusively use Nuke, so as part of the transition from Shake, all of Cinesite’s proprietary Shake tools were being ported over to Nuke. There was a process of evaluation and debugging throughout the project.
What was the biggest challenge on this film?
Our biggest challenge was by far the duration of the project. Some sequences were worked on for over a year, so keeping perspective and ideas fresh was a challenge.
Was there been a shot or a sequence that prevented you from sleeping?
No. We have built a very strong team, of both production personnel and artists. We always plan ahead and try to schedule ourselves properly to complete the work without breaking ourselves. Being the 7th Harry Potter movie, Tim and his production team have a very well established pipeline and always provide us with as much clear direction as they can. It’s really a pleasure to work on these movies.
How long have you worked on this movie?
Initial bidding and design began in May 2009.
What was the size of your team?
I lead a core team of 9 compositors.
What did you keep from this experience?
It is a real honour to play a part in bringing to the screen the final portion of such a cinematic legacy.
What is your next project?
I’m currently supervising Cinesite’s 2D work on HARRY POTTER AND THE DEATHLY HALLOW Part 2 so my journey with Harry hasn’t ended just yet!
What are the 4 movies that gave you the passion of cinema?
1. LAWRENCE OF ARABIA
2. STAR WARS: A NEW HOPE
4. THE INSIDER
A big thanks for your time.
© Vincent Frei – The Art of VFX – 2010