On Rune Animation
6:00 AM | Michael Eilers | Comment on this story
Two new reports have surfaced that deal with the technical side of the third-person hack-n-slash title in development by Human Head known as Rune. This title began with the classic Unreal engine, but the team at Human Head has modified and made additions to this base to create a game stunning in both visuals and gameplay. If you have a desire to know exactly what those changes were, an article posted at RuneNews and an interview posted by Stomped go into detail about the new animation system behind Ragnar's vicious axe swing.
Rune uses a 'skeletal' animation system quite different from the type of animation currently used in games such as Unreal Tournament and Quake 3 Arena. Instead of using pre-defined 'poses' which are swapped one after the other to create the illusion of movement, skeletal animation uses simulated 'bones' to allow a model to be animated in independent segments. Rather than model twelve versions of an arm to create an animation of a player waving their hand, an animator can simply define a start point and an end point to the 'wave' motion and the skeletal system can fill in the blanks with as many movements as necessary. This results in player and enemy models that can have thousands of movements (and even multiple animations at once, like rotating the head while running) rather than the somewhat 'brute-force' methods used in earlier games.
Here is an excerpt from the article by Gwynhala at RuneNews:
Rune uses fully skeletal animation. This means that each model is stored in only one position, and then animation data is applied in real-time to bend and post the model as needed for different moves like walking or attacking. It's very different from the kind of animation you find in older 3D games like Quake III or Heretic II or Jedi Knight. In these games, the model is pre-animated in every possible position, and all of these positions are saved in a huge model file. This is called vertex animation, and its main advantage is that the animations can be played back without a lot of CPU power. Vertex animation has some disadvantages, too: the model files can be huge (a typical Heretic II model is 3 Megabytes with about 1500 frames of pre-rendered animation), and it's very difficult to adjust the animations to different playback speeds (or different game frame rates) without making them look jerky, and it's difficult to add new weapon or spell animations to the model. A skeletal animation system like that of Rune takes more CPU power, but it allows for perfect adjustment to match the frame rate and also allows for easy combination of separate animations for different body parts and weapons.A bit technical, we admit, but sure to inspire salivary activity (yes, drooling) in tech-heads who are anticipating this title. A simple translation would be: no more stiff, jerky, repetitive movement or models that hold eight different weapons with the same canned hand position.
Now that we have delved into the animation of Rune, let's hear from one of the animators. Stomped has posted an interview with programmer Paul MacArthur. Among other topics, MacArthur comments on the skeletal animation system as well, describing how it is used in the game to enhance both realism as well as aesthetics. Here is an excerpt:
Stomped: While Rune uses the Unreal engine, you have obviously have modified it for the game's needs. Can you go over briefly what kinds of things you and the other programmers have done to the engine for use in Rune?One particular use of this technology that we found most striking on both occasions we have seen this game in action is how the heads and eyes of your opponents track you as you move -- quite eerie. We are looking forward to playing the final version of this game, being ported by Westlake Interactive and due in late October from Gathering of Developers.
Gwynhala's Report on Rune Animation
MacArthur: To me, one of the coolest technology features is the dynamic skeletal systems. It basically allows the game logic to manipulate the character's bones on the fly. Any of the bones can have a number of different properties like springs and elasticity. Then you can apply forces to these bones and they will move around according to the properties you've set. These properties override the regular animations so the result is the mesh animating as normal, except for the bones you're manipulating. One thing we use it for quite a bit is on plants in the world. You bump or swing at a branch and just that branch moves in the direction you hit it, oscillating back to it's rest position. Of course, there are many other applications for this technology, as you'll see throughout the game.
Stomped Interviews Human Head's Paul MacArthur
Official Rune Web Site
Gathering of Developers
Human Head Studios
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