EddieOffermann dot com

I was talking to a friend today about what I'm doing with regards to managing data through an animation pipeline using XML. The more I work with it and the farther I get into the project, the more flexible and powerful the whole thing seems. Of course the goal to doing the implementation in Python is that virtually every software package in the vfx industry is python-friendly - so once the core routines are written, everything from Nuke and pyShake (the python plugin for Shake - if you haven't seen it yet, check it out here) to Maya, Houdini and RealFlow will be able to make use of them. I think most places are doing that these days, with a few nods to TCL/tk here and there - but broadly supported scripting languages are King and open description formats like XML are Queen.

My friend marveled at how nice it would be if one day, a couple years from now, everything was able to talk that smoothly: that a character animated in Maya could be pulled into Houdini, for instance, as something other than an OBJ sequence or a separately rigged character that you had to tediously (or with a lot of specific coding) link to exported channel data.

I wonder if that interoperability thing will ever extend beyond each individual studio's implementation. Everybody has a way of getting software to talk amongst themselves, some solutions being more elegant than others, but when you invest in creating something as elaborate as this it becomes your own proprietary tool. If you develop a tool that an animator can take an animated character with a complex rig on it, arbitrarily select additional elements that were never *really* meant to be animated and animate them anyway, and the modeling team can modify the model and issue a new version of it - and the animation gets seamlessly transferred over to the new model, even able to be read into RealFlow, substituting a different set of low poly independent objects that are driven by the data in that XML file: you don't put that pipeline tool on the internet for everyone to download for free.

That tool becomes your secret weapon. As a studio with an investment in a powerful and unique proprietary tool, even charging for it may not mean as much to you as the edge you gain during the heat of production.

Being XML based and implemented in Python does put my current project a wee bit closer to being an open standard, though. Even Shake will take Python scripts now - and they're really powerful in it and getting more so as development continues. The readability thing for XML is a gigantic plus, and the way it represents data is great. I can build a module that will write out the translation of a locator in both world and local space, as a baked set (every frame has a value) and as a set of keyframes (values only for those frames where the value was explicitly set by the artist), as well as screenspace UV values - so the same XML file could reconstruct a scene for a lighter to light and render from or another animator to tweak the animation curves, or for RealFlow to drive low-poly proxy objects with to disturb a drifting mist, or for a compositor in Toxic to link an effect to. And it's all one XML file - not a half dozen formats (often multiple versions of each) and a hundred-unit sequence of geometry exports.

I am officially in crunch...

It's mini-crunch, though, because we're just working to get things together for the trailer. Most of the staff isn't actually working overtime, but there's a few of us... the dynamics/fluid guys, an animator or two, the cg supe and me, piecing together the necessary bits to get the shots ready for the trailer.

I wish I could be a little more clear on what exactly it is I'm doing... When the trailer comes out in a couple weeks I can at least indicate then what segment of the film I'm addressing - I'd rather leave that part as a surprise for when the trailer hits (not to mention that talking about things like that would get me in hot water).

In a sufficiently vague sort of way, I can say that there's a segment I'm working on right now that's around 76 shots long, each ranging from 50-300 frames, that has a common element that's travelling between them. Our tracking team has been tracking that element, and its progress through each individual scene, for each of those 76 shots (and at least that many more as well that I'm not dealing with yet).

The particular task I've been working on is basically a continuity script. It's a MEL script that gathers all of that data: cameras, animated and matchmoved elements, and stitches them together end to end in a master shot. This way, the element that's moving through the scene will maintain an accurate location relative to the CG environment.

To coincide with what's happening in each shot, it's necessary on that big grandaddy master shot to make adjustments: turn something here, nudge something there... and that affects the path of that common element throughout all of the individual shots.

Do you see where I'm going with this?

Basically, if we imagine that I'm talking about a man driving a car across the salt flats in Utah (not at all what's happening in this film), there are features on the horizon that we want to be consistently and realistically moving in relation to the view of the car. If the driver swerves to miss a rock, we want to change the path he's taking across the salt flats (even though in the original plates, that driver would have been sitting in a stationary vehicle in front of a bluescreen, with some hydraulics underneath making the car tilt and sway to add realism). Our view of the car from the camera should stay the same... Car and camera must maintain their relationship... but the position, speed, orientation, etc of the car and camera combined will need to change. If there's a guy on one of those sail-carts out there, we need to make sure his path is realistic and that he's in the right place in the background of each shot...

Remember that the car, the driver, and the camera are often the only real things here... the sail-cart, other things on the horizon, in fact the entire salt flats... all are cg or augmented with cg.

So I've been developing tools for funneling data from all of these shots... everything from camera data to object matchmoves, world-space offsets for each shot, and animation data... stringing it together into a seamless master scene, manipulating the paths and locations of elements in that master scene and transferring that data back into the individual shots. If we need our hypothetical salt-flats driver to swerve this way and that across several separate shots, I'm making sure that it doesn't just "kinda look right" but that we can get that data integrated into the object and camera motion of several live camera plates.

If somebody didn't ask me if I could do it, I'd probably have never thought it could even be done.

If I'm kinda scarce around here in blogland, it's because I'm catching a much-needed nap in between long shifts.