Re: 3D camera matchmovers

[P3D Tim Waddy <waddy@xxxxxxxxxx>]

> Date: Sat, 7 Jun 1997 22:38:42 -0600
> From: P3D Bob Wier <wier@xxxxxxxxxxxxxxx>
> To: photo-3d
> Subject: Matchmover?
> Message-ID: <9706080432.AA20406@xxxxxxxxxxxxxxx>
> 
> I was watching Jumangi (again) this afternoon and listed under the
> ILM technical crew credits was "Chief 3D camera matchmover".
> 
> Since we have some subscribers in the film industry, can anyone
> enlighten us as to what this might be (true 3D or motion control, or what?).
> 
> THANKS

The 3D of "3D camera matchmover" is not stereo. 
It's 3D of 3D Computer Generate Imagery once again.

The "Match movers" are one of the least appreciated, most critical crew
in making a C.G.Special Effects work. If they fail, the shot fails.
If they succede, so much about generating the effect becomes easier.

The CGI element must be rendered from exactly the correct perspective
to match the perspective of the plate it is destined to be composited into...
the same lens, same (virtual) position, same tracks, pans, tilts, zooms
jolts and shakes. A locked off shot is actually more forgiving of a
perspective mismatch. The Chief 3D camera matchmover is on set to survey as
many relevant dimentions in shot as possible. Thier first task will be
to reconstruct a virtual set. Then for each shot, the camera must be placed
to view the virtual set just as the the real camera viewed the real set.
Stereographers should appreciate the perspective difference a very few inches
can make. That is the camera matchmover's margin of error on every frame.
Whether the  matchmove is achieved through funky automated propriatory
software or human "eye-balling" the resultant camera matchmove is the bedrock
of subsequent CG work. Nothing much the process precedes it.

The advantage of motion control shoots in CGI is that the camera movement
*should* be perfect both for repeatability on the set, on a scale miniture
and in the computer.

Unfortunately for producers, most film effects simply cannot be contained 
on a "motion control" stage although some motion control stages
seem monsterously large when you are standing under those hugh cranes.
The logistics and expense of these hugh motion control shoots 
is often prohibitive. This is clearly the case for Jumangi. Not even the
largest sound stage, let alone motion control stage can contain a stampede.

I take my hat off to the camera matchmovers.

How did the release prints of Jumanji get so flashed? A matter whose depths
I've yet to plumb.

Tim Waddy.

On another note, has anyone seen the T-1000000 Terminator stereo, 3 screen, 
65mm entertainment extravaganza at Disney, Orlando? 
Does it .. work? Is there a non-SFX stereo show anywhere I can see? 


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