sheep.handturkeystudios.com

Last month we completed a 4-second animation of a wizard casting a spell for the header of a new gaming website to be launched called The Gamers Universe (click if you want to cheat and see the final product first). Though I had a very limited timetable with which to complete it (about 20 hours), I had a lot of fun creating this animation. Because of that, I’ve gotten permission to write a little ‘making-of’. Big thanks to the folks at The Gamers Universe and BlueKey (the site developers). Read on to watch the animation and read about the process of creating it.

Armed with a few reference images, my task was to design, model, texture and animate an elderly wizard casting a spell. As this is an animation, the very first thing that I wanted to make sure we got right was the motion and timing. For this, I used a generic ‘bathroom stall’ stick figure (fashionably accessorized with a low-polygon beard and moustache so I could see where he was facing) and quickly created an animatic in Blender. You can see this below (or, if you can’t view flash, watch the mpeg-4 version).

This, of course, got forwarded to the client for review and approval. While that happened, I began modeling the wizard. He’s an older guy, so I knew he was going to need a pretty wrinkled face. To deal with this I used Blender’s multires mesh editing and sculpt mode to age and wrinkle him. The problem, though, is that a sculpted mesh like this is way to heavy with geometry for animation. To deal with that complication, a normal map needed to be created from the high resolution mesh and mapped to the lower resolution one that is much better suited for animation. This raised a second complication. At that time, Blender didn’t bake normal maps in tangent space. Fortunately for us, a member of the Blender community named Zelouille posted a work-around on blenderartists.org that used Blender’s node compositor to generate a normal map in tangent space, just like I needed. This gave us an adequate normal map to complete the project. Since then, the development version of Blender has actually acquired the capability to bake tangent-space normal maps as well, and I daresay it works even better than the (very clever) node setup Zelouille provided. Below are lo-resolution version of each for your comparison (node-generated first, Blender baked second):

Since the head was already UV unwrapped for the normal map, I took a few minutes to create some[very rough] color and specular maps. I also cheated a bit and baked out an ambient occlusion map from the high resolution mesh and made it serve double-duty as a bump map to try to enhance some of the creases in the normal map.

After the rest of the character was modeled, the next big challenge was getting some hair on this guy. After briefly experimenting with polygon-based hair and determining it simply wasn’t going to suit my needs, I turned to particles. At this point Jahka’s popular ‘particle branch’ of Blender had not yet been merged with the main trunk. Rather than deal with the complications associated with learning a new system that was still under pretty heavy development, I decided to try and stick it out with the existing particle system in Blender. For the most part, I’d say it worked out fairly well. I created separate emittors for the moustache, beard, eyebrows and head hair. Each emittor was placed on its own layer and in that layer I placed additional curve guides, and spherical force fields to control the behavior of each particle system. This was an arduous task and often made me wish I’d just throw a hat on the guy and let it be over with. Ultimately, though, it turned out fairly nice and the empties controlling the hair could be pretty easily animated. There were a few rough spots, but for the final resolution of the animation, we decided that they wouldn’t be too distracting.

Next came rigging and animation. Fortunately here I could take a bit of a shortcut. I already had the very basic rig used for the stick figure in the animatic. It didn’t have all of the controls I needed and needed to have it’s proportions adjusted to match the wizard, but the big advantage is that all of the basic keyframes were already set with the proper timing, as approved and agreed upon in the animatic. This was an enormous time saver. I only had to adjust my sizing and add additional controls for the face, hands, and cloak…. and of course skin the mesh to the armature. Fortunately, this process was probably the smoothest part of the entire production.

With that done, the final step was all that was left: making it look ‘pretty’ by doing some post-processing in the compositor. This was pretty straight-forward, with only two things to note. First, in order to get the wizard’s glowing hands to light his body, I used radiosity. Looking at the render times in retrospect, if I were to do this again, I might use a point lamp instead. That said, using radiosity worked out pretty well. And by running a radiosity pass to the character’s render layer, I could control the intensity of the radiosity’s effect on the wizard. This, I combined with a new node in the compositor called the Glare node. This gave me really nice bright streaks when his hands began to glow.

After consulting with the people at BlueKey, it was decided that something should shoot from his hands as he casts the spell. This, too was done with particles, but rather than re-render the whole thing out, it was a pretty easy process to render the particles as a separate pass and overlay them on the character in the final composite.

And with that, the animation was done (watch the mpeg-4 version if you cannot see the Flash video below).

Any questions?

This entry was posted on Sunday, December 9th, 2007 at 5:05 pm and is filed under Blender, Projects. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.