Special Effects 101 (was Re: What Could Have...)

[caliburncy at yahoo.com]

I have only a very layman's understanding of special effects but I 
will do my best to clarify as Cindy requests.

A quick note that because Cindy asked about most of the "poor" 
effects, those are what I am addressing.  There are *several* well 
done effects in HP that deserve note, and like I said, they are 
mostly the more subtle ones.  A good effect is ultimately not a "wow" 
effect, but one that is seamless enough to continue suspension of 
disbelief and that supports the story.  This is true even in highly 
special effects-dependant films.

--- In HPFGU-Movie at y..., "Cindy C." <cindysphynx at h...> wrote:
> ---Luke wrote:
> > The computer graphics were typical with all the typical problems
> > (and even a couple not so typical, like my continued inability to
> > understand what is so difficult about making a proportionately-
> > accurate CG Harry).  
> 
> Could anyone expound on this a bit?  Are we talking about
> the "rubber Harry doll" on the broom and the one on the troll's
> back?  Is it something else?  I'd like to understand a bit more
> about what the actual limits of special effects are, if anyone on
> the list knows.  In other words, did the filmmakers just cut
> corners, or is it just impossible to get this sort of thing to be
> convincing?

Yes, I am talking about the Harry that is being flung around on the 
troll's back.  Because I was not involved in the making of the movie, 
I do not know for certain, but I am 90% positive that this Harry was 
created with computer graphics imaging (heretofore CGI), not using a 
rubber doll.  Had it been the latter the technique used for filming 
would have been stop motion.

Why not use stop motion?

Four reasons.  One, since the troll is CGI, it is much easier to make 
Harry CGI too; rather than making one CGI and the other stop motion 
and then trying to digitally edit the two together.  Two, Harry is 
flung about in a matter that is physically impossible for a real 
human being (unless they had pure cartilage running through their 
body instead of bones) and therefore could not have been achieved by 
a stop motion action figure either, as they are similarly 
inflexible.  Three, stop motion animation is by necessity more jerky 
than regular filming and therefore does not work as well for really 
high-speed, flinging back and forth movements like this.  Four, stop 
motion is ultimately *extremely* time consuming, because you have to 
position the figure for each frame, snap that single frame, and 
continue similarly for the entire sequence.  If you mess up a single 
frame, you have to start the entire sequence over (unless you film it 
digitally, which I assume is a possibility now, yes?).

So why does the result they achieved with CGI look so awful?  
Computer animation can be done either manually or through motion 
capture.  Obviously motion capture was not a possibility here, 
because to be able to film a stunt Harry being flung around like this 
(without breaking his spine in the process) would eliminate the need 
for the special effect altogether.  :-)  So the animation has to be 
done manually.  Often when computer animation is done manually it has 
the opposite result of stop motion--it's too fluid rather than too 
jerky.  Darned if I know why, but that's generally the case.  So the 
animation itself often looks a little unrealistic: like it's not 
weighted properly or its defying the laws of physics.

All this is pretty much an inherent problem, so I don't really fault 
them for that.  The only thing they could have done was dedicate even 
more manhours to it in the hope that they could touch it up a bit.  
(I also think they should have avoided adding fake motion blur with 
CGI to create the illusion of things moving faster than they actually 
were, but some of this is simply a framerate issue.)

But what is, in my opinion, less excusable is that CGI Harry is 
disproportionately skinny.  This, ultimately, is just the fault of 
whoever made the digital wireframe.  CGI has a lot of limitations 
currently, but nowhere in that list is the inability to make things 
proportionately accurate.  That's just a drawing problem.

> Don't crucify me for saying this, but I really have to wonder if 
> these problems would have occurred with a director more experienced 
> with special effects.

Most likely, yes, they still would have, I think, but let's take the 
two cases you presented.

> Like James Cameron or (gasp!) Steven Spielberg.

Okay, I admit that if James Cameron were in charge, the special 
effects would have been better.  The movie would have been worse, 
most likely (though I do like Cameron's work--especially the 
original, much longer (and improved) version of The Abyss), but the 
effects would have been better.  But that's really a special case.  
Cameron is an uncharacteristically technical director.  He knows the 
technical end of the business down cold and often gets directly 
involved with the effects himself.  So he really knows what he wants 
*and* a high degree of how to get it, not just the former.  Most 
directors are simply not able to do this--nor do they really need to 
be able to, in my opinion.

With Spielburg, though, I expect the effects would have been about 
the same or only negligibly improved (and again I think the movie 
would have been worse).  With my fairly minimal understanding of how 
Spielburg works, I don't think he is as *directly* involved in 
special effects as Cameron is, so it would ultimately come down to 
who he hired out to handle the effects, and for all we know it might 
have been the same people that did the effects under Chris Columbus.  
Can't say that for certain, but it's a hunch, since for all we know 
the recommendation of those companies came not from the director, but 
from Producer David Heyman or someone else entirely.  The only other 
people he might have hired instead are Dreamworks and Industrial 
Light and Magic.  Those two studios are rather talented, though, so 
who knows?  Particularly Industrial Light and Magic might have helped 
because they are more inclined to go with tried-and-true techniques 
instead of immediately assuming that everything *must* be CGI.

> Perhaps the trick is to look at the concept drawings or prototypes
> and spot early on (based on experience) that something is amiss,
> and perhaps these more experienced directors would have caught
> these things.

Well, the only effects that I really felt were *conceived* wrong were 
the troll and the centaur.  All other special effects issues seemed 
to be matters of execution, not conception.  The problem with the 
conception of the troll was that, at least in my opinion, he should 
not have been so cartoony in his design, especially around the face.  
Admittedly the scene is supposed to be a bit comic, but it stretched 
the suspension of disbelief.  I'm coming to the centaur next, so I 
won't mention it here. 

> ---Luke again:
> > the centaur was atrocious.
> 
> I'd like to know what happened here.  What went wrong?  I couldn't 
> really put my finger on it.  It seemed that the proportions were
> off or something, maybe.  Like there was a man standing there with
> a horse body attached to his back, perhaps.  I was just wondering
> if anyone on the list knows what the "fix" for this is.

Well, in my opinion, it was again a conception issue because they 
made the *entire* centaur CGI.  If I were on the special 
effects "advisory board" :-), I would have recommeded that they film 
an actual human for the upper body and combine it with a CGI lower 
(horse) body.  It is simply not currently within the realm of CGI to 
make a very good human face for *numerous* reasons (limitations on 
numbers of polygons and anti-aliasing, textures, textures, and 
especially textures).  We're close, but not there yet.  So the look 
of the centaur's face reminded me of something from the claymation 
days of "Clash of the Titans".  No, no, it would have been much wiser 
to use a real human for the upper body.  This is in fact pretty easy 
to do (it's accomplished in the same way that they made "floating 
body parts" with the invisibilty cloak, I think), so I have *no idea* 
why they didn't.

> I wonder if the Quiddich scene would have been helped along if it
> had come at the end of the film.

I'd have to say no.  That takes too much focus away from the 
Sorcerer's Stone as the primary conflict.  Once you have passed the 
primary conflict, any other conflicts are, by necessity, anti-
climactic.  The reason the interhouse cup in all the HP books manage 
to avoid this issue is that they are more resolution than conflict: 
at the time of the awarding, there is nothing else that can be done.  
But to have a Quidditch match *after* the primary conflict is already 
solved would have people wondering: Eh?  Why isn't the movie in the 
resolution stage now?  Why is it still going?

-Luke