The Komodo Dragon as a Potential Mascot for the Field of Visual Effects

[Revised 12/11/2012]

The purpose of this post is to bring to your attention an example of a truly original behavior in an animal, in this case the Komodo Dragon.

I find animal behavior fascinating, and I have no doubt that animals are intelligent, even though scientists, or some scientists, claim that they are not sure.   I think most dogs are more intelligent than many people I know and they are certainly of a better character.

One reason this topic has come up, is because there has been a low level effort to find a mascot or symbol for the field of visual effects and computer animation in the motion picture industry.  A bulldog might symbolize determination, an eagle might symbolize vision and integrity, a zombie might indicate mindless devotion, and so forth.   After all, doctors have their snake, California has its bear, the Orioles have their bird, maybe we should have a mascot too.

Ideally any mascot chosen for visual effects would communicate something about the field and people in it, and not just be chosen because it is cute. A good mascot / totem might inspire us by their example and help stimulate an espirit de corps that could cut across the various competitive companies and encourage us to achieve excellence.

Recently, I came across an animal with a truly amazing behavior that has been observed in the wild, and I want to suggest it here as a possible candidate for our mascot.

A very cute Komodo Dragon taking a nap on a rock.

The Komodo Dragon (http://en.wikipedia.org/wiki/Komodo_dragon) is the world's largest lizard. It lives in parts of Indonesia and it is famous for many things. It is famous for having a saliva that is so nasty that one bite and the victim will go away and die of the putrescence that comes from the bacteria in its drool.   The Komodo is famous for eating anything that moves, including its own children. The little Komodo Dragons apparently learn to climb trees to stay out of the way of their parents in case one of them should suddenly decide to want a snack.  

But there is one behavior above all others that distinguishes the Komodo from other animals. In order to understand the significance of this behavior we first have to go over the normal eating behavior of the Komodo.

The adult Komodo Dragon may eat no more than once a month. Its preferred meal is a small pig, goat or deer which it likes to eat whole, live, in its entirety, in one gulp. Basically they inhale dinner, or that is the idea. Then they will sit in the shade and digest for several weeks, up to a month, being careful not to get too hot.  When done digesting, he or she will vomit out the indigestible parts such as the skull and hooves and wipe the disgusting slime off its snout on a rock.

But often a piglet or appropriately sized dinner is not available so the Komodo inhales what it can of the available animal, and can get caught with an unhappy pig or goat in its mouth, half in and half out.  Obviously this won't do, so the Komodo has to figure out how to get the intended dinner all the way in.

How does it do this? Other predators might stun the intended victim with a venom that paralyzes the victim or makes it unconscious. Or it might want to kill the victim first, bite it into chunks, and then eat it a piece at a time.   But this is not what the Komodo Dragon does.  

What the Komodo does is to run at full speed with the pig/goat/deer in its mouth and slams that part of dinner still visible into a tree (or other large object) in order to bash it all the way in.  If dinner is not all the way in after the first bash, it will back up and charge at the tree repeatedly head first, or if you will, goat first, until the goat/pig/deer is completely inside.  

Komodo's have been observed knocking trees down in this way because of their enthusiasm.

What a creative approach!   What enthusiasm and ingenuity it demonstrates!  It reminded me at once of the enthusiasm and determination that a visual effects facility uses to get a project.   And of the same sort of compassion and genuineness with which someone in visual effects works with a co-worker and many, many other aspects of our field.  I still see the resemblance whenever I read about the Komodo Dragon, this one behavior completely recreates for me the sense of the deepest motivations of so many of our peers.

Anyway, I wanted to bring this to your attention in case people felt that this might be an appropriate mascot for visual effects.  

Wikipedia page for the Komodo Dragon

http://en.wikipedia.org/wiki/Komodo_dragon

Admin Notes 12/8/2012

Whenever you see a pause like this, it usually means that while many drafts of blog posts are written, there is nothing that I feel all that comfortable publishing.

The posts in progress are on the topics of architecture and history in Los Angeles, the early days of computer animation production, topics in visual effects, topics in gaming and conflict simulation and modelling, and a variety of random cultural opinions.

We are approaching a deadline that I am not very ready for, so that will affect the blog until that is over (sometime in mid January).

Hypnotic Mind Control in Cinema: The 5,000 Fingers of Dr T (1953)

We now turn from the topic of the use of rocket launch attempts as a mood elevator to a highly related topic, "hypnotic mind control" in cinema.

Hypnotic mind control is the process of forcing a person to do something against their nature under the commands of some, generally evil, person through the process of hypnotism. Hypnotic mind control is rarely used to have this person do something beneficial against their will, sadly, as that might be an interesting twist on this established but regrettably underutilized plot device. (1)

Of course, hypnotic mind control is a subgenre of a larger body of mind control techniques, including being enslaved by a vampire, demonic possession, the use of drugs to destroy the will of the victim, cult religion or voodoo, to name just a few of the most popular. Zombie films are a related but different genre, because although the personality and will of the victim is suppressed, the victim is not really controlled by anyone, except perhaps the compulsions of his own degraded brain, or what is left of it. Hypnotic mind control is distinguished from the others by being based on a process in which the subject is gradually placed into a receptive state in which ideas and compulsions are placed into the subconscious and keyed to various hand gestures and words, and yet the real personality is not destroyed, it is underneath, latent, and can be restored.

Of course this all has something to do with sex, but that will be the subject of another post.

Each of these different processes of mind control has a different mechanism from the others and has different methods of prevention and cure which become important plot points in their respective sub-genres.

"Cartoon Realism" is a term of art that I use to describe the use of live action, set design, costumes, animation and visual effects to create an apparently real, live action, cartoon world.   Who Framed Roger Rabbit (1988) is the poster child for this genre but there are others as well. 

Today we feature an important but little known film, Dr. Seuss' 5000 Fingers of Dr. T (1953).

Here is an excerpt from our featured movie in which the widowed mother of our protagonist and hypnotism victim is recaptured by the evil Dr. Terwilliker through the process of hypnotic mind control:

The work for the Happy Finger Method must go on!

http://www.youtube.com/watch?v=TSm57EGetRM&feature=plcp

The 5,000 Fingers of Dr T is the only feature length film written by Dr. Seuss. It is a comedy, of sorts, in which a little boy (played by a wretched child actor who I hope lived his life in shame because of his performance in this film) is being forced to learn to play piano. His piano teacher is played by one of my favorite comedic actors, Hans Conried, in the role of Mr. Terwilliker, aka Dr. Terwilliker. The boy is so bored with learning to play piano that he falls asleep at the keyboard and dreams the rest of the movie.

In his dream, his piano teacher becomes the evil Dr. Terwilliker of the Terwilliker Institute who is using hypnotic mind control to control the minds of mothers throughout the country to force their children to learn the "Happy Finger Method" to learn to play piano. The evil Dr. T has built a piano with 5000 keys which he will use to force 500 annoying little American boys to perform piano at the Grand Opening of the Terwilliker Institute, thus demonstrating even vindicating the Happy Finger Method.

As Dr. T himself admits, he is a villain who is executing a fraud on the mothers of America, he hypnotizes them and takes their money to pay for fraudulant piano learning technique. He keeps a dungeon for people who play other musical instruments and those who would oppose his evil plans. Here is the brief musical number with which the dungeon is introduced. There was originally a third floor, but the cowards who made this abomination of a movie were too spineless to leave it in.

Notice Hans Conried's  hand gesture instructing the executioner and elevator operator to go down a level.

http://youtu.be/G70dcCx-YP8

How can a movie with such a great premise fail so badly? Well, since you asked: bad casting, performances, direction, characters and script.  The horrible direction and performances of all of these actors, except of course the brilliant Hans Conried, condemns this film to the dungeon of "Films that throw away their promise and will never be forgiven."

Nevertheless, Hans Conried is memorably over the top in his performance, and it is worth seeing for that.  Well, maybe not the entire film, which is dreadful, but a few scenes are worth seeing.

I think that we should give them credit for attempting to create a "cartoon realistic" world using set and costume design and only a very few what we would today call effects.   There are a few matte paintings or similar technology, but very few, I think.   Too bad the movie is so bad.

Which brings us to the point of this lesson: : "Interesting design, sets, costumes and effects will not save a bad movie."

Nevertheless, the work for the Happy Finger Method must go on.

The IMDB and Wikipedia page:

http://www.imdb.com/title/tt0045464/

http://en.wikipedia.org/wiki/The_5,000_Fingers_of_Dr._T

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(1) I have a vague memory of there being some film or TV show in which someone is hypnotized to do something good against their will, but I do not recall what it might be. Perhaps some reader will remember and send me email.

Rocket Launch Attempts and Their Many Uses

This post will review various space program "launch attempts" (e.g. rocket failures) in the context of the study of animation techniques, the history of the cold war, and as a short term anti-depressant.

A real test of a visual effects studio is its ability to both animate and light things like explosions, dust clouds and water, the classic effects animation topics.  There are a variety of reasons for this, and one of them is talent.  These types of phenomena come under the purview of the effects animator, a rare and usually undervalued skill.  The way to get around the talent problem, I have always found, is to use computational fluid dynamics to simulate the effect and thus substitute technology for talent.   For excellent real world examples of CFD animation and lighting, look no further than the space program launch attempts.  They are complicated, robust, generally show very interesting lighting (including internal lighting), happen in both night and day, and are well documented from several points of view simultaneously.   And best of all they are free, or almost free.

I have selected several sequences from a collection of such things that I bought years ago on DVD, an excellent collection of launch successes and failures from different points of view, with narration done by a member of a rocket club who seems to be knowledgeable about these launches.  Unfortunately, I can not remember the name of this rocket club that produced this collection, and I can not find them online, yet.  But when I do, I will post a link so that hopefully you can order your own copy should you wish to do so.

Continuing on the theme of animation technique, these launch attempts are excellent examples from the real world of both anticipation and follow-through.   We know that something bad is going to happen, we have to wait for it, and then when an explosion finally happens there is almost always a pause, then another explosion, bigger than the first, often flying debris, or a sense of falling, then another explosion.  This is part of what makes it interesting.  Compare and contrast this with a normal explosion as seen in a stupid movie (oops, I meant to say movie, not stupid movie, how silly of me) when an explosion just happens once, bang.   No, no, no.  What you want is an initial explosion, then another, then another, that sort of thing.  Second, notice the complexity and the additional layering of debris, often with very different momentum and physical characteristics than the initial or primary explosion.  E.g. the pieces that fly off a rocket and fall at their own rate.  This complexity adds authenticity.

A variety of launch attempts have been uploaded to Youtube and a few more are on the way.

Atlas Centaur Launch Attempt:

http://www.youtube.com/watch?v=mUsUwn5awkE&feature=youtu.be

Juno 2 Launch Attempt:
http://youtu.be/MOBCT6AIvX8

Titan 1 Launch Attempt:
http://youtu.be/T0gofrDOWh0

http://www.youtube.com/watch?v=ZEeSxJ6dXdc

http://www.youtube.com/watch?v=q47VhdmJwv8

Moving on we now discuss the two related topics of the history of the cold war and of non-traditional anti-depressant technique.

During the cold war the Soviet Union was so presumptious as to attack our civilian space program, accusing it of being a transparent front for our military space program.  Years have passed and I have examined this charge and find that it is only 99% or so accurate: in fact our civilian space program was transparently a front for our military space program.  Our space program had several different purposes, of course, but first and foremost it was a deliberate way to take the high road on the competition for the hearts and minds of the people of the world in the context of the cold war between the two "civilizations".

Finally, in the larger context of finding ways to relieve the vast ennui and despair that afflicts so many of my friends (not me, of course), I find that watching rockets explode many times in a row is good for stress relief, similar to popping a lot of bubble wrap, for some unknown reason.   Its a short term relief, but it does seem to work both for me and for a few people I have tried it on.  Unfortunately to do that well, I have to get more examples online, and I will gradually do so.   (This is a continuation of a theme on non-traditional anti-depressant technology, which I first started in this post).

The Atlas rocket family on Wikipedia

http://en.wikipedia.org/wiki/Atlas_(rocket_family)

The Atlas-Centaur on Wikipedia

http://en.wikipedia.org/wiki/Atlas-Centaur

Will Life of Pi Bring Audience Credibility Back to Computer Graphics?

I have noticed for many years now, that the audience has started to associate computer graphics with bad visual effects. Time after time I read on the Internet that such and such a movie had stupid computer graphics in it, and that the movie was the worse for it.

I find such comments to be distressing for many reasons, not the least of which is that there is some truth to the criticism. There seems to be something about visual effects and computer graphics which can cause a producer, or director, or studio to lose their minds. Who needs an original plot point or clever idea when you can just blow up another city? Also, ever mindful of the bottom line, they are eager to reduce costs by eliminating inessential elements, like the writer.

Another cause of this association between bad movies and computer graphics is the relentless publicity machine which grinds out a behind-the-scenes documentary for every film on the glamourous and rewarding world of computer animation. Of course, those of us in this field who have experienced this firsthand are pleased to be in the public eye after so many years huddled around a glowing screen in a dark room, that is only natural, but ultimately the film is not about the bold new technology but about the story, and the people, and what it means to us, the audience. The visual effects is no more important than the soundtrack, in fact the visual effects are usually less important than the soundtrack, yet you do not see a billion documentaries celebrating the composer and the sound effects artists, etc.  You only see a few such documentaries, which I think is more appropriate.

There is a saying in the world of visual effects that "good effects will not save a bad movie". It turns out that this is not entirely true, there are a few exceptions to this but onlly a few. And it turns out that really bad effects can damage a good movie, see for example the movie Them (1954) which will be the subject of another post.

But when you have a director who gets it, and knows how to use the medium, and has a story to tell, then you may end up with something that makes everyone look good and achieves the promise that motivated many of us to be in this field, and to help invent it.

Such a film is Life of Pi (2012) although I admit I have not seen this film (I like to wait a few years, like 20, to let it age and improve). All the reviews are fabulous, and they all talk about the excellent CGI that delivered the main character.

So, congratulations to everyone at Rhythm & Hues for delivering a project that may single handedly redeem computer graphics in the eyes of the audience.

Now Kitty, promise to be nice to Mr. Fish.  

But lest I appear too positive and upbeat here, and thus be out of character, let me remind you what the future holds. First, R&H will be inundated with scripts that are completly original and never been done before and involve a large animal (lion, tiger or bear) in a small space (lifeboat, spaceship, cabin in the woods) and a young person (boy, girl or indeterminate) in a desperate journey or adventure.

And not all of these will be directed by Ang Lee.

Will the sequel be called "Life of 2 Pi"?

Rhythm & Hues:

www.rhythm.com

Life of Pi at Imdb:

http://www.imdb.com/title/tt0454876/

Transcendence in Visual Effects: Expressing the Inexpressible in Shaolin Soccer (2001)

As we have previously discussed, visual effects can be used for purposes beyond mere reality, but can be used to express an emotion, or the inner life of a protagonist, or in this case the experience of attaining spiritual enlightenment.

When seen in this light, most visual effects are revealed to be the empty shells that they are: communicating nothing of value, the mere posturing of one giant robot to another, of another wall that explodes, a car that crashes or the actions of a zombie going through the motions of being a human but empty of genuine human thought or emotion. It is a tale told by an idiot, signifying nothing.

But when the purpose and talent of the filmmaker uses visual effects for a higher, more noble purpose, then visual effects can add tremendous value to a film.

In this example, from Steven Chow's Shaolin Soccer (2001), visual effects is used to show the triumphant return to enlightenment of the former and debased monks, who through the discipline of soccer and the humiliation of being defeated through the deceit and immorality of the practice team, achieve enlightenment on the soccer field. Thus the fire that appears behind them when they open their eyes, is the fire that is experienced by the soul when it attains this spiritual state. And the practice of playing soccer is a metaphor for how the secret techniques of the monks of Shaolin can lead to a better and more actualized life in the so-called real world.

The sequence is here:

http://www.youtube.com/watch?v=WFTP4Xj9Q-s

It is not clear which school of Buddhism is being presented, it may be an esoteric form of practice. But I have no doubt that the practice exists or should exist as the seriousness of purpose of the filmmakers comes through in every frame of their film.

A better use of the technique of a modified "bullet time" does not exist and many doubt it could exist, so perfect is its use here.

The Wikipedia page:

http://en.wikipedia.org/wiki/Shaolin_Soccer

The IMDB page:

http://www.imdb.com/title/tt0286112/

Miracles from Molecules

(This post is in progress).

I miss the cold war, when not everyone was using computers to steal money and distribute pornography, and we thought a new world was coming, a world with freedom and economic security for everyone.  A world where the rich would not oppress the poor, where disease would be defeated, and where everyone could explore their full potential, irregardless of the circumstances that the accidents of their birth allowed.

This is the world that the composers of the post-show of the Disney/Monsanto Adventure Through Inner Space celebrated.  I was listening to this song this morning and I felt compelled to transcribe the lyrics, an artifact from a past that imagined a future very different from our present.

Please watch your step as you leave the vehicle and step on the moving walkway.  

The composers of this song created a perfect statement of the triumph and potential of modern (e.g. 1960's) chemistry and sings the praises of a new hero, the industrial chemist.  The song is called "Miracles from Molecules" and it was composed by the Sherman Brothers (1) for the Walt Disney Company.

      Miracles from molecules are dawning every day
      Discoveries for happiness in a fabulous array!
      A never ending search is on, by men who dare and plan,
      Making modern miracles from molecules for man!

      Every atom is a world, an infinity unfurled,
      A world of inner space without an end!
      A world of mystery, of endless energy,
      With treasures more than man can ever spend!

      Miracles from molecules, around us everywhere,
      There are miracles from molecules, in the earth, the sea, the air!
      Now men with dreams are furthering what nature first began,
      Making modern miracles from molecules for man!

      Making modern miracles from molecules for man! 

The song encapsulates the early 1960's vision of the future and the promise of a world with unlimited energy, and new materials that solve previously unsolvable problems, a world without limitations, amen. This was a  vision of hope when some would despair in a world of poverty, war and the threat of nuclear destruction.  It was for all of us, the worldwide community of Americans of whatever nation, all citizens of this new and synthetic world that was right around the corner.

Of course you had to be 12 years old to believe in such a thing, and a naive 12 years old at that.

But at least it was a vision of a better world, and stated with total sincerity, in a large-scale corporate marketing world exposition sort of way.

Today, do we hear a similar refrain from the promise of nanotechnology?   Perhaps, but they don't have a catchy song yet.

Get on the moving walkway and follow the arrow to your future.

A simulation of the complete attraction with the official soundtrack, is below.  This song is part of the post-show and it starts at approximately at approximately 8 minutes, 20 seconds into this video.

http://www.youtube.com/watch?v=KA3uFkF1A9o

My previous post on the Adventure Through Inner Space is below.

http://globalwahrman.blogspot.com/2012/11/the-mighty-microscope-recreated.html

_____________

(1) Richard and Robert Sherman composed a tremendous number of songs for the Walt Disney Company, for both films and theme parks.   Not only "Miracles for Molecules", but also the lead song from the Carousel of Progress as well as It's a Small World.  Both of these will be subjects of their own post.  A Wikipedia page for these two is at:
http://en.wikipedia.org/wiki/Sherman_Brothers

The Psychological Effects of Flare in Dr. Strangelove (1964)

One of my favorite things in the world is flare. I mean flare like you might find in photography, not "flair", which is also good, but something else. Flare is a lens aberration that comes from light reflecting off elements in a lens. I mean a REAL lens, not the fake lenses that one finds in computer animation or the fake lens flare programs people sell for photoshop. I mean the real flare that comes from real lenses, particularly older lenses, that comes from light being being deflected from where it should be going, to the emulsion or sensor, and instead bounces around inside the lens, willy nilly, going whereever it damn well pleases.

The type of flare I am talking about has several kinds of effects. One kind of effect is on the image (loss of contrast, washing out the blacks, causing halation or a glow around bright objects, etc). But it has another kind of effect as well, a wonderful effect. It has a cognitive effect, or if you prefer a psychological effect. We have learned that when you take a picture in bright sunlight, that the image will be washed out. We have learned that when you take a picture of a bright object, that there will be a distortion of some sort of the picture. We have learned to expect to see halos around lights in night photography. And because we have all learned this, and don't think about it anymore, we can use this to create in an image a different feeling or persuade you to think you see something that is not there.

So, if I am simulating a city at night, or an airplane at night with bright lights on it, then it is a standard approach to create a halo or some other artifact around each of the lights that are supposed to be bright. Back in the days when people did model photography, they would reshoot a scene with only the lights visible, everything else black, in order to get a "light pass" which could then be composited in. Think Bladerunner (1982) or Close Encounters of the Third Kind (1977). These kinds of effects are all throughout these two films. (The effects facility was the brilliant Entertainment Effects Group in the Marina, now long gone, and the work was supervised by Doug Trumbull and Richard Yuricich, both ASC.)

But there is one sequence of all that is my favorite use of flare. It is all through this sequence, a sequence that I consider one of the best in all of film, and no one ever notices. This is "the bomb run" from Dr. Strangelove which is six minutes long and is the last six minutes before the bomber drops an atomic bomb on a target in the former Soviet Union. It is the sequence where they run through the checklist for the bomb and try to get the bomb bay doors open. Among other things, it has a very young James Earl Jones in the role as bombadier ("Negative function, sir. Bomb bay doors do not open, sir").

Here are some images from this sequence.

There is flare in every one, and a lot more in the sequence itself. It is completely subliminal and I promise you that it is not accidental. I say that with such assurance because before Stanley Kubrick was a director he was a professional photographer in NYC. And no photographer is unaware of flare. Not a chance. This was deliberate and I think it adds to the atmosphere of the world inside the bomber.

What a shame that lens designers work so hard to remove flare from modern lenses. Progress, I guess.

There is an ok copy of the bomb run at the following link. The particular sequence I am referring to is from 3:00 into the clip to the end.

http://www.youtube.com/watch?v=KTo-iFBu14U&feature=related

Zeiss explains their T* anti-reflection coating in this youtube video:

http://www.youtube.com/watch?v=mtmQgoOZ3cw

An Example of the Genre of the Making of VIsual Effects Films

One of the weird phenomena that surrounds the tremendous "success" of visual effects, is the self-destructive documentary that describes how the effects are done as part of the publicity of the film, no matter how irrelevant the visual effects may be to that film. Whatever movie it may be, it has a documentary about how the visual effects were done. First the premise of the documentary is silly, the visual effects are anything but glamourous yet the documentary will almost always make them seem so.  Second, it is self-destructive because telling everyone how we do the work is like a magician revealing how the trick is done, it takes away the magic. How "special" will "special effects" be if everyone knows about how we do what we do? Third it is often lies, that is often not the way the effects were actually done. So that is good at least, you see we didn't tell everyone how we did the work, although we did tell them how we often do the work, just not that particular shot which was complicated and annoying and who would want to be bored with the actual details? Besides maybe the details of how that particular shot was done would reveal a mistake or maybe that bold new technology that we were using to sell the show didn't actually work all that well, and had to be augmented by animators and technical directors fixing every frame, and how much fun would that be to tell the movie-going audience who doesn't really care about the boring details anyway?

Fourth, anyone who knows the world of visual effects knows that it would be extremely unlikely for one of these documentaries to be in any way humorous, satirical, sarcastic or self-critical. Not in a 100,000,000 years. With a few exceptions, people in visual effects are deadly serious. Tell a joke, go to jail. Use a big word, they think you are making fun of them (seriously). At least in this country.

So it is to the UK that we must turn for the best commentary about visual effects I have seen in any media, and it is in the form of a mock documentary looking back at primitive visual effects as they were done at the end of the 20th century as part of a 2006 BBC show called Time Trumpet.

Did he really say working with actors is like "herding zombies"?  Oh my!

Avoiding annoying and unnecessary spillage of beer on the set.

Notice how they call a green screen stage a "CGI studio". I think it is somewhat funny that computer graphics has become so famous that people think that a standard visual effects technique is or must be "computer graphics". Nevertheless, this is one of the best satires I have seen about visual effects.

The documentary is at

http://www.youtube.com/watch?v=UjhBf4vlTw0&list=PLPVUAquAnllvLn_lcO2BSuUoXwguvRtfS&index=1&feature=plpp_video

Information about Time Trumpet is at

http://en.wikipedia.org/wiki/Time_Trumpet

How To Make Someone's Head Explode

[This will be one of the many posts that include details about famous effects shots that I have picked up over the years.   It is all anecdotal information, believed to be true, but I wasn't there.  When this film was shot, I was in a dark room at Robert Abel & Associates writing their raster graphics system.]

As an exercise, I want you to think for a moment about how you would make someone's head explode.

As it turns out there are many ways to do this (in visual effects, of course, not in real life) and they all work with varying degrees of realism and at various costs.

Many of the films that might want to cause someone's head to explode are also low-budget horror films, those with the least amount of money to execute their vision. So I think we can say that one attribute of a method to make someone's head explode is that it should have a modest price and hopefully contribute a lot of value to the film.

Generally speaking, these are the things we are looking for.

1. That the head that explodes looks as much as possible as the real person's head. 

2. The audience should not notice the switch from the real to the standin.

3. The explosion itself should have character and not be a generic explosion.
4. The exploding head should interact with the set in some suitable way, e.g. brains, skull parts, etc. 

Although there are many ways of doing this kind of shot which could use any number of different techniques (miniatures, prosthetics, all digital, etc), best of all would be that it was "practical" in some way. "Practical" is a visual effects term of art that refers to an effect that you can use on the stage and when it is shot in live action it is in some sense done. There is no more to do. A radio controlled squib that spurts blood in simulation of someone being hit by a bullet is an example of a practical effect.

Arguably the best solution of this cinematic problem was realized by the movie Scanners (1981) as directed by David Cronenberg. The script describes a war between a small number of telepaths who are trying to take over the world and who have the power to read minds and also, with some effort, to cause someone's head to explode. Near the beginning of the film, a security organization gives a demonstration of telepathy to an audience of security professionals and, not realizing that they have been penetrated by a "bad telepath", played by actor Michael Ironside, the "good telepath" and the "bad telepath" struggle.   Evil wins in this case, and our victim telepath explodes.   Or rather, his head explodes.

As you can see, the telepath on the right seems to be reaching for a certain, climactic head position.

The solution was completely practical. A life mask of the good telepath in an expression of great pain was made, as well as a dummy of the rest of the body, dressed in the same suit. The live action of the scene was shot with the good telepath emoting his great unhappiness and reaching the same position and expression of the mask. A second sequence is shot with the camera in the same (or a similar) position, but instead of our actor we have a dummy, whose hands are gripped in an indication of great stress.  The mask on top of the dummy is given appropriate makeup and appliances, such as the eyeglasses, and filled with fresh chicken skin and Technicolor Blood #2. Then a shotgun is placed behind the dummy and pointed to the back of the head, out of sight of the camera, bolted into position, and rigged to be fired remotely. They then start the camera, set off the shotgun, and record the results for a few seconds. I am guessing that they use a high speed camera.

Then the two different takes are edited together such that the cut to the dummy happens a frame or so before the shotgun goes off. Of course they had to find a place to cut where the real actor had reached the head position and facial expression to match the dummy and mask.

The shotgun blows away both the mask and the contents, which then fall heavily, showing both excellent gravity and a sense of "follow through", onto the chest of the dummy. The effect itself makes good use of the animation principles of replacement animation, gravity, anticipation, follow-through and appropriate sound effects to enhance the visuals.

Its a beautiful effect which truly accomplishes what it needed to accomplish, which was to blow someones head off in a way that was dramatic and memorable and yet be very economical.   You could use the same technique today and it would work very well. 

Here is the trailer on Youtube, unfortunately in poor quality. It captures the essence of the scene in context however, if you want to see the blood more clearly there are other examples on Youtube that show that, but this shows the context, which is so important.   Please ignore the stupid music and graphics at the beginning and end of the trailer.  This was 1981 after all, a more primitive time.

http://www.youtube.com/watch?v=PmJC3ZaXBEc&feature=fvwrel

I have found a much better trailer, this one for British audiences.  Unfortunately, it does not show the head explosion as well, but it is superior in all other ways.   On review, I have decided that this is probably a completely different head explosion from that found in the movie.  I wonder if it wasn't made especially for this trailer.   Some other post will discuss the context of how trailers are made, it is probably different than you expect.
http://www.youtube.com/watch?v=d6GNs6MthtU&NR=1&feature=fvwp

I have left out a picture of the exploding head, because it is too disgusting, and I am very sensitive to images of former people who have been turned into a bloody mess.   

The IMDB page for Scanners:

http://www.imdb.com/title/tt0081455/