Thursday, March 5, 2009

DIGIT PREVIZ ARTICLE

1. What are the key stages in your process for creating an animatic?

Well, essentially it all begins with a script or at least an idea. The studio or production company usually provides us with an initial draft script and a shot breakdown, which allows us to analyze and bid how many vfx shots are planned for the film. With the aid of the previsualization supervisor, the VFX supervisor and director can determine which sequences require the most conceptual and technical attention. If the project is an animated stand-a-lone film, the process is similar but additional attention is given to the process of rough and final layout, which is an entirely different process and occurs a little further down the production pipeline from previs.

Previs for animated films is entirely conceptual in nature and works in conjunction with the story development team to refine the boarding process in 3D. The layout department will then translate that conceptual previs into the confines of the animated 3D environment. Live action film, on the other hand, not only has a conceptual element, but may also be saddled with specific technical needs to address real world situations and stage space issues in advance of shooting. Animated films are far more forgiving thanks to working entirely in a digital environment.

Once the client’s expectations have been fully clarified and the job awarded, the previs team is assembled and begins work on two primary tracks. The artists are normally assigned to various asset and model-building tasks, while the previs supervisor normally creates a preliminary scratch and editorial track utilizing storyboards provided by the studio. This 2d “board-o-matic” is helpful in determining shot timing and pacing within the sequence. The previs supervisor also breaks sequences down and assigns shots to various animators within the previs team.

Asset building and “ramp up” time is usually the slowest stage of the entire previs process and can require up to several weeks depending upon the complexity of characters, environmental needs, and motion complexities. Usually a well-established previs company will have a number of these assets and IK rigs already available, however, each circumstance is different and the time required can change.

Once asset building and initial timing is complete, shot construction begins. A typical sequence is normally assigned to a small 2 or 3 man team. Smaller teams allow for greater uniformity and continuity between shots. They will proceed to animate individual shots that are then assembled into a cut sequence by the previs supervisor (or editorial department in a larger studio). It’s the previs supervisor’s responsibility to clarify and manifest the director’s vision for the film to the individual artists. As the sequence comes together, there will be various shot and sequence reviews by each of the major supervising powers. The Previs/Layout Supervisor first, the Animation/VFX supervisor second, and the Director third. This review and revision paradigm continues until the sequence finalizes into its first final form. Additional sound fx and sweetening are done to round out the sequence and it is presented to the Director for final approval.

2. What do you need to consider before starting?

First and foremost, it must be determined if the sequence in question is being constructed for conceptual and storytelling purposes or if it needs to be more technical in nature. Conceptual previs is used primarily to tell the story, determine timing, define camera angles / lenses, and figure out which shots work and don’t work within a sequence.

Technical previs is more about determining exactly how far the camera is from an object, how much green screen space the director has, potential gimble requirements or if there are any physical restrictions in real world space that may interfere with actually obtaining a shot. Its goal is to provide hard data.

It can be very difficult to attempt to do both processes at the same time. Finish the conceptual process first before moving on to the technical issues because the one will ultimately drive the other.

Additionally, a strong understanding of the timeline and budget will restrict various options concerning the look and level of detail applied to each sequence.

3. Any tips for the best way to approach the task?

Communication between all the supervisory powers is essential.

If working on a live action film, obtain the camera package and film aspect ratio details from the director of photography and ensure your digital cameras correspond precisely.

Shot tracking aids the process of supervising the work.

Review shots and sequences on the previs supervisor level daily, while leaving the Director to review larger milestones. Daily interaction with the Director sounds nice, but it can rapidly spiral out of control if micro managing starts to occur. A proper balance between the director and the previs team must be found.

Don’t worry too much about character articulation in your first pass. Step animate and pawn characters to obtain simple blocking and camera positions first.

Try to utilize a referencing system in your 3D program to swap out or update characters easily.

Use hardware rendering to speed up production. Use software rendering for the final version, if time permits, or if the scene is heavily dependant on environmental rendering factors that cannot be adequately visualized in hardware rendering.


4. Are their different techniques for different outcomes?

Previsualization is very fairly universal but can mimic nearly any form of cinematic style. The point of previs however, is to make the movie accessible for review to the director before committing larger amounts of money to an unproven shooting scenario. Shooting time on set is far more expensive than a small 3D team working behind the scenes. It reduces the director’s stress level and provides him with a detailed shot template. If that can be done with miniature objects and a handheld mini camera, 2D cut-outs in After Effects or full 3D animation, the end result is still the same; a more efficient production.

5. How complex do animatics have to be? What is the general level of complexity?

Animatics come in all levels of complexity. They can be as simple as 2d scanned cut outs assembled in After Effects or lush 3D environments and articulated characters that nearly mimic the final product. It’s all dependant on budget, philosophy model (conceptual or technical), timelines, and the director’s need for precision. Experienced directors, especially those from a VFX background, may not need to see the intimate detail because they can “see past” a low rez, non textured object where as other directors require high levels of detail in order to satisfy their need to “see the movie” play out in advance thus proving a concept or evoking the proper emotional response. Hardware rendering and playblasts along with limited modeling, texturing and step animation are generally considered the “norm”.

At POV we prefer to stand out from the norm by providing fully articulated characters, robust animation, textured environments, lighting and software rendering for a refined look. The extra effort really helps sell the emotional quality of storytelling.

6. Any tips on how to edit and polish the animatic?

Editorial is the best time to start correcting issues of continuity, screen direction, and timing. Allow your artists time to see the cut in progress rather than waiting till the very end to see a finished first pass. This will allow for a more rapid response to gross errors in continuity and screen direction. The more artists you have on a sequence the more difficult this becomes to manage so keeping sequence teams small comes in handy. Make sure your previs artists are trained in cinematic language and concepts. They should be fully versed in understanding composition, continuity, camera angles, and other “rules” of filmmaking.

7. How do you integrate the pre-viz work into the production workflow?

This is highly dependent on which philosophy of previs you’re using on the film. Generally conceptual previs is strictly used as a storytelling device and is rarely used to transfer hard data to a vfx company. However, if it is your intent is to integrate your work directly into the production pipeline a strong working knowledge of the vfx company’s chosen software and procedures are in order. Specific issues like knowing the proper unit scale, rotational order, precise camera back settings, aspect ratios, lens packages, set and environmental factors, and data exporters will be necessary. If your software is different from the vfx company’s software, you may need to build specific plugins to export your data to their format, or utilize software that supports .bhv or .fbx file formats. As long as you only animate what a real world camera can do, you should be fine. Cheating previs to elicite faster turn around times only brings misery down the road.

8. Can you think of any do’s and don’ts on the subject of previz and animatics?

1. Always use the proper unit scale for the show and work in real units when possible.
If a director wants to know exactly how high the camera is off the ground, you need to tell him in real world units, not some arbitrary value.
2. Do not scale objects in order to animate forced perspective.
Scaling objects to increase the speed of an object traveling to or away from camera is bad previs. Use a proper lens instead. If you can’t do it in the real
world, with a real camera, don’t fake it in previs.
3. Avoid freezing transformations or animating the pivot point once animation begins.
A number of VFX houses request real world locations of objects and camera
data after completing previs. Freezing transformations or modifying the pivot
point during the process will report an incorrect offset to the objects’ location.
4. Release models for referencing with origins always at 0,0,0 and the pivot in the proper place.
Failure to do so will cause a cascade in the positions of models when updated in
the referencing system.
5. Don’t animate focal length unless specifically asked to do so.
Animating the focal length is ok for specific situations. However, if the film is
shot animorphically, focal zooms may introduce a considerable amount of shake
into the shot, making tracking and precision alignment in the compositing stage more difficult. Dolly the camera instead.
6. Don’t change the established frame rate to speed up or slow down animation.
If you have to speed up or slow down the speed of the animation, do it properly
by modifying the keyframes, not the frame rate.
7. Don’t alter the digital camera’s aspect ratio or aperture once established.
Once your digital camera back is aligned to match the DP’s lens package, changing it will certainly cause problems and lens values may not match.
8. Don’t change the rotation order of the camera or objects once established.
As with translational information, VFX houses generally have a specific rotation order for cameras and objects they wish to maintain. If you are providing data to a VFX house and you have to change the rotation order of an object or camera to prevent gimble lock, be sure to annotate the shot so they can reorder the data accordingly.
9. Use correct naming conventions and version numbers.
Make it clear and self-explanatory.
10. Use only the approved lens package for the show.
The DP has a specific range of lenses available for the director to choose from. Using non-approved lenses or odd sized lenses that don’t exist doesn’t help anyone.
 

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