Good animation advice from Bobby Pontillas on breathing,

some wonderful art of pixels and Wild Things,

moving drawings at the Pencil Test Depot,

… and notes, slides, and other materials from GDC…

Just came back from the excellent Annecy 09 animation festival, and a short stop in Paris for the AIgamedev conference, the latter marking my first attempt at public speaking as a game developer.

I was invited to participate in a panel on how animation combines with AI to create interesting character behaviour, which has been a pet-subject of mine for a long time…

I think it went well.

At Annecy, I saw Coraline (which was amazing) and a loooot of short films. Also met a bunch of cool people, both there and in Paris.

A bit of Half Life 2 and Team Fortress 2 this time…

One thing Valve does very well is make it feel like you’re present in the world by having characters react to you. Subtle things make all the difference…

In Half Life 2, people look you in the eyes. They don’t stare… they look and look away, their eyes darting from place to place. If you shine your flashlight in Alyx’ face she squints and covers her eyes.

The most elaborate animation is reserved for scripted sequences: intricate, often spectacular scenes that break up the action. You are free to move around within certain boundaries and characters respond to your location by glancing sideways or turning to face you, but… they remain essentially linear cutscenes. The overall sequence of events does not change based on your actions.

The line though, between the scripted and dynamic, is slowly fading and it will be interesting to see where this goes…

There’s a clever mechanic that began life with Alyx in Episode One and was further refined in The Orange Box and Left 4 Dead: Based on context, characters will say short lines of dialogue in reaction to what is going on around them, sometimes very specific things…

It would not be a stretch to imagine using the same AI that picks appropriate dialogue to pick gestures and other actions to make NPCs respond to the world not just in words, but in movement…

A different beast, Team Fortress 2 is interesting in its use of silhouette to distinguish characters. Each member of its ensemble is instantly recognizable at great distance through shape and style of movement. Just as well, as you’ll want to adjust tactics accordingly, or suffer an untimely demise…

The characters’ appearance matches their gameplay function.

Personality is all too rarely explored in game animation. Clearly it can serve both as icing on the entertainment cake and as core gameplay information.

Worth a mention too are the dynamic facial expressions in TF2. They seem to reflect player health and success with excited and fearful expressions, though, perhaps more significantly, they make screenshots completely hilarious.

Next up: Cecropia’s The Act

Today, Outcast…

It may be cause for concern that a ten year old game still merits inclusion, but it is a testament to just how far ahead of its time Appeal’s open-world adventure really was.

There were many things that made this game, but I will focus on two:

Gratitude and directions.

When you arrive in Adelpha you are something of an unknown quantity. Much is expected of you, but the general populace will not believe in you until you act to help them.

Dispatching a convoy of hated soldiers will gain you much appreciation. It will also change the behaviour of the NPCs around you. Previously observed in silence, now you are greeted with salutes and encouraging gestures.

It doesn’t directly change gameplay, but it creates positive feedback that makes the world feel alive, like your actions matter…

NPCs in Outcast don’t stay in one place. You often need to go look for people. This would be annoying if it weren’t for the game’s fantastic directions-system. You can stop anyone and ask for the whereabouts of a particular NPC. The AI is such that it remembers where it last saw a character and will tell you roughly where to go.

“Yes Ulukai, I saw him going north some time ago.”

So you head north and ask someone else.

“You want that Talan, there,” he says as he turns and points to your right.

He doesn’t say “that character is just east of me“… he turns and points. To this day I haven’t seen any other game do this.*

Simple gestures or expressions can be so much more powerful than dialogue…

Next up: Ico & Shadow of the Colossus

* as a core mechanic, outside of cutscenes

First up, Assassin’s Creed…

No doubt its movement and environment interaction are a milestone in game animation, weaving elegantly through crowds and running effortlessly across rooftops… but there is another aspect of this game worth noting: the guards.

If you turn off the HUD, you may notice that you can tell the guards’ alertness by their posture alone. If all is well, they stand and patrol normally… You can quite literally almost get away with murder. If something suspicious has set them on edge, they clutch their swords nervously. You should NOT at this point do something stupid to draw their attention.

When you hear cries of “WHO did this?” and see them patrol with swords unsheathed, the slightest provocation will cause them to notice you.

CLARITY

It’s a simple thing, but extremely effective… conveying the same information as the HUD indicator, only without breaking immersion. Recognizing their behaviour allows you to adapt yours.

Now I may be alone in this, but I would argue it’s actually kind of a cop-out to include a HUD at all. If you have something that communicates by itself, adding competing channels to say the same only serves to clutter up the message…

WALKING THE STREETS

Another interesting aspect of Assassin’s Creed is its “social stealth”.

To blend in and move anonymously through these urban crowds, you must act as if you were just another citizen…

Drawing a weapon, running around and climbing on things will almost certainly blow your cover and send the guards chasing after you. As long as you haven’t been spotted, you keep your cool and resist the urge to run.

Movement is literally separated into “low-” and “high-profile”. While the latter gives you the most freedom, the former is crucial to staying out of sight.

High-profile movement is fast, agile and violent, while low is soft and discreet. You switch instantly between modes – a more gradual transition with ‘degrees of rudeness’ could have been interesting, but it seems the developers decided against this as it “started to explode” in terms of complexity. Perhaps just as well for the sake of clarity (if not to avoid an obscene amount of extra animation)…

The game is making you think about your own body language.

You can even pretend to be a monk by walking among the faithful with your head down and hands clasped together in prayer. The designers made an odd choice here by forcing an automatic walk when tagging along with groups of monks, which makes the player feel less clever for doing so… but the idea remains a strong one.

For whatever faults it may have Assassin’s Creed is a groundbreaking title, with inventive use of NPC and player body language as a key part of gameplay, which I hope the developers will continue to build on in future…

Next up: Outcast

Nevertheless, I found this an interesting read.

Intriguing ideas with regards to NPC interaction through dialogue. In particular the RPG prototype mentioned towards the end has a great deal of potential well beyond text-only interaction, tying in neatly with my personal pet subject of exploring communication through body language (in this case illustrating trust).

Speaking of which, Cecropia has this wonderful little experiment on their website which I think exemplifies the kind of stuff animation can bring to gameplay.

* And yes, I appreciate the irony in stating this on a blog. Just don’t talk to me about ebooks.

Not any less interesting was the online publication of a series of lectures and interviews conducted by Warren Spector at the University of Texas exploring the history of Looking Glass, Ion Storm and others. They were quickly taken down due to a combination of bandwith issues and something about not being ready for prime time, but myself and a few others have kept the videos up for download while we wait for the official links to come back.

More good stuff:

Will Wright at GDC 08

Various Valve lectures in PDF

Shawn Kelly’s compiled tips & tricks of animation

Shawn’s a great guy. I sent him a few emails back when I was a total newbie and he was very generous with his time and advice. Above text is a collection of all the stuff he’s written for the (excellent) AM newsletter.