Creating Middle Earth

Tolkien’s Lord of the Rings is a formidable challenge for any movie maker. The only way the fantastic world of Orcs, Hobbits, Wizards, Trolls and, of course, humans could be brought to life was by going in for extensive computer graphics imagery

Thursday, January 02, 2003

It is not normal for one effects company to be dedicated completely to one project. But Weta Digital of New Zealand has been working exclusively on the Lord of the Rings trilogy for over three years now Weta uses a mix of machines and OSs to achieve its task of keeping Tolkien fans glued to their seats wanting more. There are SGI machines running IRIX, Intel machines running NT and Intel machines running Linux on the render wall. Then there are high-resolution Macs used for real-time playback of the rendered footage. Some of these are dual-processor machines and some are single-processor ones, and there are multiprocessor servers, as well. By the middle of 2002, there were over 2000 processors at work on the Lord of the RIngs out of which 1300 were on the render wall.

Every frame that is shot is scanned in for digital treatment. Each frame is 12.5 MB and each second of film is made up of 24 frames. Storing all this requires a massive amount of storage. Weta has 75 terrabytes (1 TB=1024 GB, roughly equal to 25 forty GB hard disks) of live backup, and by the time the work on the first movie was over, it had accumulated almost 200 TB (5100 40 GB hard disks) of data. By the time the trilogy is complete, Weta could well be holding one of the largest amounts of data being held by an SFX company. By the middle of 2002, it was already the sixth largest. All this data moves from machine to machine over a Gigabit Ethernet backbone, over fiber. The backbone has a minimum of 4 GB bandwidth, and it is not as if all of it is inside the facility. One switch is five miles away from the studio.

After the render is finished, the rendered footage is shot back into film for duplication and distribution.

Impressive equipment by any standards. But that is not the most talked about when people discuss the making  of the series. That credit goes to Massive.

Massive is the software that was specifically written to create the huge battle scene at Helms Deep in the second of the series, the Two Towers. This battle features over 50,000 participants. Typically, such scenes are done using particle animation. Each participant is treated as a particle, and moves back and forth according to simple laws of particle dynamics—attraction, repulsion, etc. After a sizeable number of such particle interactions have been created, they are duplicated and rendered to give them the required shape. The problem with this approach is that the dynamics become too simplified and repetitive. Massive was written to overcome this situation.

Massive handled this problem by endowing a form of artificial intelligence to individual fighters, with individually adjustable physiques, and other characteristics. This gives a sort of realism to the rendered action, with each individual action by a character being determined by preceding actions of itself as well as the others it is interacting with, which in turn is derived from their individual characteristics. The battle in the Twin Towers features fifty thousand warriors.  By the time of the third movie in the series, the number of warriors would triple!

But, it has not always been smooth sailing with Massive. Apparently, in one of the earlier simulations with the software, using just two warriors, the two turned out to be so balanced that they never fought! In another simulation shown at the O’Reilly Open Source Convention, some of the combatants from a group seem to have had enough of the fighting. They just wander off from the scene of action! One of them then seems to feel bad about having wandered off, and promptly returns to join battle. To avoid such situations in the final footage, Massive’s programmers test out the characters they generate, weed out the ‘inefficient’ ones and clone the good ones. These clone warriors are then ‘individualized’ by adjusting their individual characteristics. Not an easy task by any account!

Maya is used extensively in the production of the Lord of the Rings trilogy. It is used in modeling, animation and lighting. But, it is not that all ‘creatures’ are of purely software origin. Some, like the Cave Troll, were first created as physical scale models. The models were then scanned using 3D scanners to create the animation model.

Earlier on in this piece we spoke of the render wall. Now, what sort of a beast is that? We saw the render farm in the first piece in this section. A render wall is nothing but a render farm, built up of rack servers, mounted on racks that look like a wall. That is all. Let us take a detailed look at this render wall. The render wall at Weta is to take about 800 servers. 350 of these are 1 GHz PIII machines. The remaining 450 are dual processor 2.2 GHz Zeons with 4 GB memory. They run RedHat 7.3. The required animation is broken down into batches and is fed to individual machines on the render wall, using workflow software. There is a set of technicians whose job is to monitor the render wall. And they have an interesting designation, Render Wrangler.

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