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AFX Selectrons and Other Goodies

by Jeff Faust · 07/28/2006 (10:53 am) · 33 comments

My previous blog entries covering Arcane-FX development have mostly been about spellcasting effects. For this blog, I'm going to set aside magic effects for a bit and present some other kinds of special effects and special effects tools we've been developing for AFX.

When we first started development on Arcane-FX, we were not thinking much beyond spellcasting and other magic effects. It was the early days of World of Warcraft, and the whole notion of AFX grew out of a determination to recreate, in TGE, the kind of spell effects I was seeing in WoW. However, once we got the first few AFX spells working, it was clear that the same mechanisms we had developed for crafting magic effects could also be used for other kinds of special effects. Now, we finally have some concrete examples.

Selectrons

It's understandable if you don't know what a selectron is, since it's a word we made up. Selectrons are what we call the effects used to indicate that a scene object is selected. They are usually used for picking a target of some kind. The target of a spell, the target of a conversation, etc.

Selectron effects were not something we planned for. We just suddenly discovered that we needed a way to make them. AFX target selections were originally a simple red circle projected on the ground below a character. It was static and fairly hardcoded.

arcane-fx.com/images/sele_old.jpg
One day Matt asked if we could make the red circle glow briefly when first selected so that it would reflect the behavior of the casting zodiacs in many of his spell designs. I spent about 10 minutes thinking about a quick and dirty way to add an animated glow to the selection circle, before I realized that what we really needed was a way to create selection effects that was parallel to the way we created spellcasting effects.

In AFX, special effects are organized using an effects choreographer. The choreographer used for spellcasting is called afxMagicSpell. To create dynamic selection effects, we made a new choreographer called afxSelectron. It's a bit simpler than afxMagicSpell, but it generally works much the same way, and this really opens the doors to designing some very interesting selection effects. And unlike spellcasting effects, you usually want selectrons to execute only on the client used by the player actually making the selection. afxSelectron takes care of this.

arcane-fx.com/images/sele_tiled.jpg
Well, what can you do with a selectron? If you prefer to show a selection using a texture below the selected object, you can do that with zodiacs. They can be layered and animated creating something much more dynamic than a static circle. If you prefer to show selections with some kind of geometry hovering above the selected object, that's easy too. Attaching separate sound effects for object selection and deselection is trivial. The selection effects in WoW are pretty simple, a colored circle beneath the selected character. But if you look closely, you'll notice that the selections are not really circles but somewhat crescent-like, and very subtly, the fat part of the crescent always points toward the camera. This camera tracking is easily reproduce in AFX by aim constraining a zodiac to the camera. Here are some stills of some example selectrons we've created.

arcane-fx.com/images/sele_acquired.jpg
The selectrons shown in the pics are dynamic, so you may get a better impression of this viewing the Selectrons movie here. Also, the movie is silent, but our default AFX selectron has separate sound effects for the select and deselect actions.

Sci-Fi Effects

Our results here are still rather preliminary, but we have started experimentally applying AFX to the realm of sci-fi and other futuristic effects. Matt's first creation is a spell-like effect that materializes a small personal attack satellite that orbits the player, executes a deadly laser attack, and then dematerializes. A nice aspect of the effect is the way that the hovering drone appears to kick up dust clouds as it moves over the ground. We think there's room for improvement in the lasers and would like to explore development of a special energy beam type projectile.

arcane-fx.com/afx_gallery/gallery_pics/sf_a.jpg
Beyond the satellite effect, there are a few details about the space helmet that are worth mentioning. In the AFX demo, when you go to the spellbank containing the satellite effect, the demo enters a simple Sci-Fi mode. It switches the targeting selectron to a sci-fi style and adds a space helmet to the player's orc. The space helmet is not part of the orc model and it is not added using the mount mechanism. The helmet is an afxModel effect and it is constrained to the orc's head using an Effectron. Effectron is the name we give to a simple one-stage choreographer that is very useful for simple effects groupings. Here it's used to add some special gear to the player character. Effectrons are also useful for adding effects to a freshly dropped item, to an unlooted corpse, or for subtle environment effects. They are also potentially useful for melee effects, and weapon embellishments.

arcane-fx.com/afx_gallery/gallery_pics/sf_b.jpg
For more, visit arcane-FX.com.

About the author

Jeff Faust creates special effects indie middleware and games for Faust Logic. --- Blog: Effectronica.com --- Twitter: @FaustLogic

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#21
07/29/2006 (8:00 am)
@ Dreamer -- For decals that conform well to the terrain, any scene object that has to perform some kind of analysis of nearby terrain in order to reshape itself, will probably be too pricey. While structurally, it's messy, it's more efficient to customize the terrain to include a certain kind of decal texture in its own rendering. The terrain looks at an active list of decal textures while rendering. Other decal texture proxies determine placement in the scene and feed the decal list that the terrain looks at.
#22
07/29/2006 (10:18 am)
It makes me want to selectron on something :D lol.. I really like the word.. sounds nice.. of course the effects are very very good.. :D

Martin @ Korpos
#23
07/30/2006 (7:17 pm)
Woah those are nice!
#24
08/07/2006 (7:33 pm)
I really like the direction that you guys are going with this. Very versatile and useful for all kinds of things. The possibilities are endless.

Excellent work! I am looking forward to its release.

-Jase
#25
08/11/2006 (8:11 pm)
This looks great and really looking forward to it, hopeing for a TSE version. Would it be hard to change it over to TSE?
#26
08/12/2006 (8:55 am)
Just a question... will this work on Vehicles?

Guimo
#27
08/13/2006 (7:20 pm)
@ Guimo - We haven't done any testing with vehicles and we haven't implemented any special vehicle oriented features (although it's a direction we'd like to explore). However, there are a number of AFX features that should work on any subclass of ShapeBase or any subclass of SceneObject, including vehicles. For example, you should be able to select vehicles, target vehicles, constrain effects to vehicles and named nodes of vehicles. attach selectrons to vehicles, use a vehicle as a spellcaster, etc.
#28
08/14/2006 (4:56 pm)
Great looking effects here!

Any clue how hard it would be to create force-shield like effects.. ie -- bullets striking/bouncing off a force shield around someone or something?
#29
08/20/2006 (9:43 am)
@Jon Paynter - It's pretty hard to guess how difficult it might be to create the effect you describe. There are so many ways to create an effect and every game has different requirements. In general, due to our initial focus on magic effects, the system is better tuned for large single projectile attacks. As we've started working more with futuristic effects, it's become clear that effects involving machine-gun-like bullet sprays, may require some special features to deal with the fine projectile granularity efficiently. Right now, with some effort and cleverness, I think you could probably put together a decent force-shield effect using AFX. Eventually there will be better features for bullet-type effects, and this will make such force-shield effects better.

@Edward Smith - A TSE version is in the works. So far I haven't seen any monumental obstacles to making it work, but the port is not trivial.
#30
08/26/2006 (3:43 pm)
Fantasic Jeff! Cant wait to buy it for my game. When's this Grimore of Greatness come out? ;)

Gib
#31
10/21/2007 (2:57 pm)
Wow, these effects are WoW quality!

Keep up the great work!
#32
02/21/2008 (8:37 pm)
Is there any way to 'levitate' the selectron, i.e. make it render higher than the terrain level?

Or rendering selectrons on static shapbe objects?
#33
02/22/2008 (6:07 am)
@ You Meng Tee -- A Selectron is an example of an effects choreographer. It manages a group of effects and is not limited to any specific location. Many Selectrons use what we call Zodiac effects to place a terrain decal at the feet of a selected player. Zodiacs only work on terrain and interiors which does limit their placement somewhat. To create a Selectron with elements that exist above the terrain you have to use different effects. For instance, a simple model of a plane can be used to place a Zodiac-like effect above the ground.
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