Animated Mummies Lurk in the Halls

September 26, 2014|
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Hello folks! The first thing I want to say is, big thanks for the fantastic feedback on the Pre-Order Trailer! You guys truly deserve a full blown sequel and we are going to squeeze our best to deliver that for you on October 15th!

These are the final days before we freeze content creation for the game and focus entirely on bug fixing and other release related technicalities. In the mean while, we animators have finally decided to break the silence and expose some of the black magic we use in our animation for Legend of Grimrock 2. Well, to be honest, actually there is nothing too sophisticated, just bare to the bone simple and robust stuff. But in case you have been wondering what’s going on in the animation department of the mysterious and secluded Isle of Nex, this is your chance to sneak in. Please, let me show you around!

Monster Rigs Variation

Monster Rigs Variation

The first thing you are going to notice in our tour is that we animate a wide selection of very distinctive monsters for Legend of Grimrock 2, all the way from mellow jelly blobs to disgusting flying eyes to giant ogres, as seen in the image above. As you can imagine, there is no one rig we can share with all these totally distinctive monsters in the game, so every monster needs a unique custom rig. In case you are not familiar with what a rig is, I would describe it as a structure inside a character that defines the way it is animated and deformed, just like the bone and muscle structure inside our bodies. The rigs of Grimrock are built fairly simply because each one is dedicated for a specific monster, which usually means only about 10-20 clips of animation, although some monsters may have over 30 different clips. The reasoning for such quick and simple rigs is that there is no advantage in putting too much effort in building complicated rigs, only to be used for a few animation clips. It takes somewhere from 3-10 days to animate all the needed clips for a monster, depending on the complexity of the monster. So spending a week only on building the rig would double the development time per monster, which would result in fewer monsters in the game. Another good reason for using quick and simple rigs is agility in the development process. The simpler the rigs, the easier it is to modify or completely rebuild them and get back to animation as soon as possible. This approach is proving fruitful especially in a small indie studio.

Technically the rigs are built of three layers that can be seen in the animated GIF below. Oh, my apologies, may I introduce you to one of the mummies of Legend of Grimrock 2! This friendly individual is always eager to give a hand 😉 Well, he may not totally creep you out now, but I promise you that these walkers will make you scream at some point of the game, trust me 😉

Rig structure breakdown

Rig structure breakdown

Lets open the hood and see what the mummy’s rig looks like. The first mummy, marked by the letter A, shows the animated monster in idle mode. Mummy B shows the three layers of rigs working together. Mummy C shows the blue rig, which is the basic level that handles all the inverse kinematics (IK) and the positioning of the joints. IK may sound to some of you like vocabulary from the old ages of classic sci-fi jargon, but for us animators it’s actually pure magic straight from heaven. It’s a built-in system in animation software that enables to easily pose the limbs of a character simply by positioning the end of a limb instead of painstakingly positioning every part of it. Mummy D shows the red rig, which we use to actually keyframe the monster. We position most of those 25 controllers for every key pose the mummy does in the animation clip. A typical clip in Grimrock would have about 30 frames (one second of animation) and about 6-10 poses, which will sum up as around a minimum of 150 positioning of controllers through the short animation clip. Please observe the image below to see an example of the key poses of the walk clip of our handy friend.

Mummy walk key poses

Mummy Walk Key Poses

In practice these poses are iterated over and over many times until the movement of the monster is perfect. So, one could say that it takes thousands of keyframed positions to create a single one second long final animation clip. For efficiency reasons the rigs are built with the minimum controllers required to create the needed poses. The idea is that less controllers means less keyframes and better productivity. However, too few controllers will make it a struggle to pose a character correctly. The idea is that the controller rig needs to be simple, but convenient to use.

The last mummy marked by the letter E in the rig breakdown image shows the deformation rig that gets exported to the game engine. This rig is separate for three reasons. 1st reason is that it is easier to handle what is exported when the rig is completely separate. It should be noted that it is important to avoid exporting unnecessary items to the game engine, not to disturb performance. 2nd reason is that it enables us to use different animation controller rigs for different clips, if needed. This way we can freely make custom modifications to the controller rig (red) for any clip, while driving the same deformation rig (multi color) that absolutely needs to be identical in all animation clips in the game. Finally, the 3rd reason is that a separate deformation rig enables us to have a different hierarchy in the controller and deformation rigs, which is quite often the case. For example, sometimes the hand’s controllers need to be parented to the root of the rig, so the hands stay in place when the torso is posed. However, in the game, the hand’s deformers must be parented to the arms in order to minimize jiggle. Our simple solution is to have the controller rig drive a completely separate deformer rig using constrains.

So there you have it, that’s how we construct our rigs. This system is simple and flexible for all of our needs. The rigs are not powered by any code or scripts. Everything is native out-of-the-box simple Softimage methods. Nothing fancy. The best thing I like about this approach is that it gives the animator independence and confidence that he is not dependent on a team of experts to handle the rigs. I feel that an animator should know his rigs and when needed, make some tweaks under the hood right on the spot. The same way a good sports car driver need to know a certain level of automobile mechanics in order to really push his performance to the limits. This kind of approach is especially helpful for a team player in a small indie studio with no dedicated technical art experts.

And lastly, at the peak of our tour, our natural talent animator Jyri Leppänen shall show you below a quick demonstration of what it looks like when a few of the Mummy’s animation clips that he animated for you are stitched together.



And if for some incomprehensible reason you have missed the Pre-Order Trailer, check it out below and pre-order now!

Buy the way, can you spot the Mummy?


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