AFX Spell-Design Blog #1 (Fire Tower)

Hello everyone. I'm Matthew Durante, the effect's artist for Arcane-FX. I've been doing my best to demonstrate the power of Jeff Faust's special effects package for TGE, as well as prodding and pushing him for new and exciting features. (When I'm feeling sneaky I'll implement something myself and wait 'til he catches me.)

Jeff and I have started work on a second pack of spell effects! We're not focusing on any specific theme at the moment, but are looking for a pack of spells that demonstrate a variety of useful effects for fantasy-genre games.

After some user feedback, we decided it would be a good idea to blog the creation of some of these spells, to give users an idea of the process of spell design. And therefore...

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I've never actually played World of Warcraft, but Jeff has, and using that and similar games as a model, he roughly categorized the spell types he'd like to see demonstrated in this new pack. On that list I saw "totems" -- this idea of a spell that creates an independent object in the environment that has some kind of long-lasting effect. When I saw examples of WoW totems, however, I was saddened, for they were not exciting. I can understand the practicality of a totem that influences player stats for all those in its proximity, like +5 sexiness for all nearby elves, but clearly this needed to be enhanced for +1000 coolness.

What about towers as totems? Clearly summoning giant towers is a core fantasy cliche, and much cooler than some floating doo-dad. Yes!

And so here is the Fire Tower:

This is a giant tower of destruction the caster can summon. The tower rises up from beneath the earth, casting aside all players in its way. Atop it forms an unrelenting sequence of fireballs that, by a deep and capriciously wicked will buried in its stone, are sent arcing throughout the environment at enemy players and places and perhaps even the caster himself. But it can be destroyed. Perhaps a group of brave orcs will bind together to bring it down...

Here's where we're at: www.arcane-fx.com/visuals/blog1-movieA.avi

I'm designing this tower effect with little thought for its behavior after it is formed. Jeff is confident he knows how to structure the scripts properly to make it work as a long-lasting environment effect that keeps shooting off fireballs. He may even be able to make it take damage. All that's for future blogs... The spell also needs a proper name.

=== Tower Model ===


The design is fairly cliche but I think it's okay; I always liked the bull-skull/horns motif. The tower was modeled in Maya, textured there and exported in .dts format. It's probably too high-poly at the moment, but oh how I hate to destroy a nice curve with tessellation. I did the texture in ArtRage and Photoshop, a kind of marbly-granite thing with some noise run through it. The model has a collision box, and when loaded into AFX as a StaticShape the orc collides as expected. There's also some rising animation on it that is first-pass.

=== Casting/Summoning ===

The current idea here is that the caster summons the tower with the use of a staff that represents the tower (which leaves us some room perhaps for reusing these effects with a different staff for other tower spells). A zodiac forms beneath the caster with a rotating pentagram, he gestures appropriately, the staff forms in his hand as it is summoned or magically-removed from his inventory, and he strikes the ground with it. If the summoning is successful, the tower rises up from the pentagram and he had better run; if not, the spell backfires with a fiery poof from the pentagram that knocks the caster on his butt.

We need to make the casting conditional because there are instances where the tower shouldn't form, such as when the caster is inside an interior object, or when the terrain is especially non-flat. While it would be awesome to see the tower form inside one of the orc hovels and watch the hovel disintegrate... that's a bit beyond what can be done, unfortunately. How this test will be performed is something Jeff is thinking about.

> Orc Animation

This is just a start. The strike especially needs more action. Perhaps more on this later...

> Staff

Currently it is untextured. It was very simple to get into Torque however. Inside the staff Maya model, I simply made sure the place I wanted the orc to grasp the staff was at the origin, and once exported, I loaded it as an afxModel and constrained it to "caster.Mount0" -- and it worked! No animation on the staff was necessary; it's all the AFX constraint system.

> Casting Zodiac


I'm going for an embedded zodiac design here: the outer zodiac is stationary and mimics the bull-skull motif from the tower, and the inner is the rotating pentagram.

I create these zodiac textures by building geometry and rendering out of an orthographic view in Maya. I generally work with nurbs to build quick shapes that don't visibly tessellate. Maya's shader glow provides nice halos. To get the noisy broken-up look, I project a 3D fractal texture through the color and transparency of each shader (with projection, I can get the fractal to remain continuous across multiple surfaces). I'll end-up tweaking the color a lot, but by doing it in Maya all I need to do is tweak the shader color (and glow color). Building zodiacs in this way is very nice and fairly fast, but it could also be done in Photoshop of course, with the careful use of layers to separate color from shape (so that you can do color-tweaking easily).


For each zodiac I render one version with color and one that is all white and glowy. The latter is used to reveal the main zodiac in a flash of white.

Once these textures are brought-in as zodiacs in Torque with AFX, it's time to play. First, I'll try to get everything in the right position. Both zodiacs are constrained to the caster, however they need to placed off-center from his location. In AFX, we use a chain of procedural modules called Transform Modifiers to further adjust the constrained parameters of an effect. In this case I used a local-offset to adjust the position of each zodiac relative to the caster and freeze modifiers to keep them from following the orc around if he moves. I also adjust the zodiac's radii (radiuseses) here to get good sizes, and put a spin modifier on the pentagram. With position, size and rotation established I take a look at timing parameters, which are adjusted relative to the orc animation. All of this is and will be tweaked as the effect evolves.

As for timing the glowing white zodiacs, which are used to reveal the main zodiac but also make the edges of the fire patterns glow, I'll have more on that later...

The problem with the current zodiac design is it seems upside-down, which just works naturally with the embedded design, but I may take another stab at it...

> Light-Beam Effects


Both the outer ring of the main zodiac and the pentagram have glow beams that shoot upward. These are needed not only because they look cool, but they are loosely-timed to actions of the orc and complement them.

I do these with polygonal meshes in Maya that are usually exported as two-sided. I'll use Maya to set up an animated sequence. Once in AFX I'll force texture attributes to be additive and self-illuminating, and specify the name of the sequence to play. I use the same local-offsets that are on the zodiacs to get the beams in the right place, then play with scale-factors so they line-up to the zodiacs.

The easiest way to animate light-beams like this is to simply key scale on the whole thing in Maya, and when the motion is perfectly vertical just scale about Z. But in the case of the outer-ring beams I wanted a more dynamic effect, so I needed to actually rig the cylinder. One bone did the trick, with the mesh smooth-bound to it. Then I just animated the translation and scale of the top joint.


This effect does illustrate a problem though: because the beam isn't perfectly vertical, it won't line-up with the underlying zodiac accurately on non-level terrain. Since the tower itself requires relatively level terrain, we hope this won't be a problem here.

As for the textures that are on these, they were created procedurally using ramp textures in Maya. This makes them easy to change, versus doing something by hand.

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And there you go, our first spell-blog. Hope you enjoyed it. More to come here and there.

Such an elaborate "totem" as this somewhat contradicts our stated goal of practical spells for the practical user.

But we've gone too far to turn back now.

- Matthew Durante