This is a discussion of animations and poses, but specific to their usage within Second Life on line.


There really are a few ways to discuss poses and animations and their differences.  Let us first of all look at a simple definition.  A pose is like a single picture for an avatar. An animation is more like a movie showing movement. So a pose generally is one arrangement only of an avatars position limbs and body part rotation - which normally just stays in that position.  Whereas an animation appears to be fluid movement.

To an animator, like me, they will likely view this differently.  Poses and animations are often done using the same exact software.  The question is really how many frames?  The quick answer to that is that a pose would normally have two frames and an animation in second life can be most often from 3 to 900 frames.  To understand the difference, we first of all need to understand what the word "frame" means to an animator.

Well, over the last hundred years or so, several geniuses in the world realized that the human eye is fairly slow moving, and also takes pictures of its surroundings much as a camera, and also retains an image for at least an instant.  And of course, we can all argue how long an instant is.  But with this eye limitation, it was learned that one could create an optical illusion for humans that seems to duplicate motion - at least to our brains via our eyes.  If one can show our eyes a number of still pictures rapidly, our eyes will retain some of those images and our brain will perceive that as fluid motion - even though it is in reality, an optical illusion.  Nothing is moving in the true sense.  So there began the huge business of the optical illusion of Hollywood and also television. Now, let us call those still pictures we are showing our eye "frames" and see how this all works.  Film motion pictures we understand use 24 frames a second.  That to our eyes appears like real motion. For US television, also an optical illusion, original broadcast television in the use was "interlaced" so only gave half a complete picture every 1/60th of a second.  A full picture then took two television pictures for interlace and that became 30 complete frames per second, similar to film.  And many of us saw that as good motion and movement via our eyes.  Some new forms of television, not interlaced but "progressive scan" can afford in the US 60 complete frames of vision to our eyes.

Ok, so then many frames -or still pictures if you prefer - as shown to our eyes maybe at the speed of 24 or more a second look to our eyes and brain as motion.  So how does this work in second life?  An animation in second life can vary the speed which is the number of frames, and the number of frames themselves, butt he general top end of any SL animation is about 30 seconds of animation, which is generally 30 frames per second and a total of 900 frames (30 frames per second times 30 seconds).  So, 900 frames max.  - in general.  Now, if that does not seem complex enough, there are 60 variables for an avatar for each frame.  There are three directions for position change, x, y, and z, but also 19 different body parts each can have different rotations of x, y, and z giving a total of 60 items of data for each frame that must be determined.  How do we get to 60?  Three position changes, x, y, and z and 19 body parts with 3 rotation values each for x, y, and z get us another 57, and hence 57 plus 3 gives us 60 variables for each of those 900 frames.

Now, one would think a pose would be one single frame, but no, at least two.  The reason for this may be an anomaly (or oddity) in Second Life that the very first frame in any pose or animation must never be touched.  That first frame is reserved for the avatar in how it enters the pose or animation change.  If one varies the first frame, all kinds of errors might result.  So the pros in SL animations never ever touch the first frame.  So then, if a pose is desired, then all of the change must be only in the second frame and none in the first.  Then animations in second life also allow looping -or a repeat of certain frames.  So, let us take a pose.  We get through the first frame which we do not touch, but maybe in the second frame we have an avatar sitting down.  Then we set the animation to loop forever on the second frame until the avatar stands.  So the avatar remains sitting until it decides to stand up.  Hope this makes sense.

For an animation, again the first frame must never be touched for second life issues, or we can get into odd errors.  But not a big deal, since 900 total can be normally allowed, we can be creative with the last 899 frames or frames 2 through 900.  Like poses, we can then set the animation to loop on itself.  For many animations we will set the loop to "sort of" loop between the frames we control, frame 2 through 900 until the avatar stands.  Recall that these 900 frames in general would bring us an animation about 30 seconds long.


At this point you might say that you have seen animations more than 30 seconds long, so you are saying no no, you must be wrong.  So can an animation go over 30 seconds in length in Second Life?  Well, the engineer in me says, well yes and no.  Don't you just hate engineers who speak in parables?  Anyway, the reality is that each animation is still only about a max of 30 seconds long.  However, then one of us nerds writes second life script software to cause a second animation to start just as the last one stopped.  Recall that this is not so different than original movie films.  Each large movie film could only last what?  not sure?  Maybe 20 minutes?  And in movie theatres a worker would watch for dots on the screen close to the end of a 20 minute film and then key on a second projector aimed exactly in the same spot as the first.  So the second movie portion took over exactly where the first one stopped, and our eyes saw no difference - if the person working the projector is good. Similarly Second Life software can key in multiple 30 second animations and make the whole thing look much longer.  Let us take the case of our multi-ball version of the Hokey Pokey.  The whole animation end to end is over 180 seconds- or just over 3 minutes long.  How does it do it?  There are 20 different animations stored inside each Hokey Pokey dance ball, whether guest or master red ball.  The master red ball tends to send a signal to each other ball about every 8 seconds to change the animation, or as in our movie analogy, change the reel.  So what we are seeing is pretty much an endless stream of 8 second films, some of which repeat at other times, and get us to a whopping 3 minutes long of what appears a unique animation.


Given all of the above, I think you can see that animations may be difficult or time consuming.  An animation for second life can be up to 30 seconds normally or 900 frames. Each of those 900 frames in turn have 60 variables of position or rotation, meaning that the animator must control 60 times 900 equals 54000 data points.  For some dances, almost every move must be precise.  Anyway, maybe you get the idea.  A lot of detail, and that might not be fun for every one.  In our case, we found animations cumbersome, so we have written some of our own RL software to help with it.  That does help a bit ... assuming a person is the kind of person who also enjoys writing software to help things like that.

Hope this tells you some of the technical insides of poses and animations within second life. And yes, believe it or not, some of us enjoy doing animations even with these complexities.

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