Regardless of the scientific or medical animation you’re working on, the first essential step is to look at and collect as much specific reference imagery as you can. Even if it involves looking at a lot of difficult “surgeon camera” shots that contain lots of blood and gore, this is the best way to understand the way our internal bodies really look. Really study the way things move and react to one another. The Internet is always a good source, as usual. Lennart Nilsson’s magnified interior body photos are a great source of inspiration for us (www.lennartnilsson.com). His images are romanticized by his photography and setup, however, and his work often has a very studio-lit feel to it. Decide early on the brief you want to follow and study different lighting techniques. We were going for a highly realistic look and recognized that most “real” internal body shots are front- and single-source lit. That single light source would often burn out and give the images an overexposed feel.

Once you have selected your top images and movies for inspiration, you’re ready to start working on your setups.

Using the creative brief you’ve been given by your client or which you set yourself, refer to the source and reference images to help you plan your storyboards. Think carefully about the kind of angles that could help add drama, the motion that gives the most realistic feel and what it is you’re trying to get across to the viewer. Is it purely explanatory, or are you going for pure drama? If you want narrative continuity, think carefully about the context and how your VFX work will fit into the storyline. If the flow is interrupted due to differing camera movement from, say, the live action that comes before it, or the grading/lighting and overall "feel," your work will be wasted. The storyboard stage is the time to sort out as much of these variables as you can, before you get to the slower digital work. Sketch the boards first and block out the action. Get feedback and then go back and make changes until everyone is happy. We’ve found that it’s best to time out the boards to the script and preceding and following shots (and block them into a rough edit) to see how everything is working.

Whatever application you choose to model in, always start by looking for accurate models that may already exist. There is no point in spending days modeling body parts and microorganisms that have already been painfully built and are readily available elsewhere. Even if they’re not perfect, they will give you an excellent starting point. Zygote has an extensive line of human body models and is as good a place as any to get very accurate facsimiles, as long as you can afford to pay for them. We’ve had a lot of success reworking Zygote models with XSI’s great poly modeling tools and are able to customize them completely.

All flesh and body parts move in a "wobbly visceral" way. You just can’t achieve this in a normal key-framing environment. We’ve found that XSI’s cloth simulation tool, though time-consuming to work with, gives great reactionary movement to surrounding organs and flesh. Test different techniques and always remember that you’ll never achieve a truly real look without secondary movement. Everything in the organic world is soft, watery and fleshy. Also consider using XSI plug-ins, such as RealFlow from Next Limit Technologies, to generate totally visceral random and unusual movement.

When you’ve got your models built, you’ll want to block out camera moves using the storyboards and reference images you made and collected. First, capture handheld camera movement and bring this into XSI. By setting up a little practical set with tracking markers, you can easily create real movement.

Spend some time speaking to your local butcher. Whether you like it or not, you’re probably going to have to buy some fleshy meat and organs from them to study. If you’re working on internal body shots, you also need to understand the level of wetness and liquid that is inside us all. Photograph and scan as many angles and textures as you can. Take the scans into Photoshop and patch them together from the UV unwrap data you’ve generated from XSI. Make sure the textures are large enough to wrap around your models.

One of the most important things you can do to make your animations feel more cinematic is to generate as many passes from XSI as you can. You won’t be able to achieve a wet look without several different black and white "wet passes." These may be reflection, incidence, specular or depth. Each pass is vital to creating a good composite.

If you can afford it, shoot real elements to add into the mix- splats on the lens, condensation, particles and steam all help to create an "in-camera" cinematic feel. I believe that if you can bring something actually shot into your CGI composite you’ll have a much easier job convincing the audience your final effect is real.

Now back to that wet look: Using the passes you’ve generated in Mental Ray, start compositing these layers. Don’t be afraid to double up and experiment to try to reach your goal. Doing something unconventional, or beyond the limits of a "normal" composite, always generates more interesting results.

Blur, depth of field, grain and camera shake all help to add to the real feel of the shot. When grading, make sure the colors you’ve chosen match the context. More important, make sure they are within the range of the real world. The palettes from video or still photos captured with an endoscopic lens and lights are quite limited and will go to the extreme and blur, go out of focus and burn out. Replicating these kinds of details in your effects shots will help you achieve a much more believable look and feel.

Tools Used: Softimage|XSI, Next Limit RealFlow, Zygote models, reference images

Philip Dobree
Director, Jellyfish Pictures
Philip Dobree is the director of Jellyfish Pictures, an award-winning visual effects and graphics company based in central London. He was the VFX supervisor on the multi-award winning VFX for the BBC series Fight for Life, generally recognized as representing a step change in the realism of internal human body CGI. The project won the Visual Effects Society award for outstanding visual effects in a broadcast series, the Royal Television Society award for best digital effects in a broadcast program, and most recently, a New York Festivals Gold World Medal. The Jellyfish Pictures team of animators and artists is continually pushing the envelope in the detailed world of CGI and digital effects.

Philip Says Keep In Mind…
When doing any kind of scientific or reality-based animation, it’s important to do a lot of R&D up front. We spent about two months preparing for this project before it went into production, developing techniques, pipelines, models and textures that would give us, once the production shots started to come in, consistent “looks” during compositing. The three main looks we established ahead of time for the television project highlighted here, the BBC series Fight for Life, were an X-Ray look; a photorealistic look, like the kind made with endoscopic cameras; and under-the-microscope closeups.