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Introduction:
For my last shot, I decided to demo a bit of matchmoving.
I'd bought a nifty new video camera, a Panasonic NV-GS75 just
for this endeavor. I think it is the cheapest 3-CCD camcorder
available on the consumer market. Originally, my plan was
to acquire an el-cheapo video camera to shoot some test footage/location
scouting, and then loan a DVX100 (DVX102 for us in PAL countries)
for a few days to shoot the reference footage. I was unable
to locate a cheap camera for use at that time; those that
I managed to find were several years old, with not much difference
in price to a new camcorder! Gah! I bit the bullet and just
got the GS75.
The advantage of shooting with a DVX100 would be progressive
scan - the footage acquired would be full frames, just like
stills out of a digital still camera. Consumer cameras and
most others out there record interlaced footage - each frame
only has half the fields.
CG Modeling:
I was originally going to model a Zoid, but decided that I'd
need to work on something bipedal. Searching through many
mecha websites, I came across this little beastie from a younger
age: The ED-209 found in the first robocop movie. It was perfect
- bipedal (though reverse-articulated), and very detailed.
References were limited though - there was a set of blueprints
from robocoparchive.com.
(For modellers, the blueprints are good for a starting low-res
mesh, but some proportions are off). I used these in tandem
with the Robocop 1 DVD.
Here are some plain renders and some with
textures. The cannon mounted on the 209 was added in quite
late. My original shot was much longer, showing the 209 returning
fire with the cannon (the gun pods were deemed inadequate).
In the end, it was cut as I just didn't like the feel of it
overall, but the cannon remained. For the fans, I'd believe
you will notice, while the overall shape follows the 209,
there are several changes made to the smaller details. Most
of it was done on a whim, and others because I couldn't find
proper reference.
Enforcement Droid 209 is originally designed by Tippett
Studios.
Rigging
Reverse articulated legs aren't much of a problem, until I
got the robocop dvd... the lower leg was connected to the
upper leg via a sliding joint! I solved this issue using the
stretchy bone setup as taught by Paul
Neale. The entire lower leg structure is attached to the
lower bone, and slides along as it stretches. This worked
great. Once the rig was done, a low res mesh was created out
of the hi-res mesh (I used the multi-res modifier), and attached
to the bones using lots of position constraints and look-at
constraints. Finally, the hi-res model was just linked to
the low res animation rig, and unhidden just before rendering.
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Other automated rigs on the 209 are the feet's "claws".
They are set to automatically clench when lifted above a certain
distance. Also, the spiral structure on the 209's legs are
also rigged to automatically twist when the leg extends/contracts.
Doubtful that it can be seen in my reel, but it's there :(
I also experimented with a one-bone rig. It worked, but the
IK method allowed joints to be angle-limited, which is more
useful. For Maya dudes, do a search on CGTalk for ed209, you
will find Kevin
Kraeer's maya setup for his ED209.
Scripted Animation
 For
most of the walk cycle, I wrote several scripts to automatically
move the rig along a pre-defined path. This really saved me
time from animating the 209, and I could set the speed, height
etc at a click of a button.
Basically, I have 3 pre-defined paths, two for the feet, and
one for the main body. Point helpers move along these paths.
The script then keyframes another set of point helpers based
on the positions of the first 3 point helpers. The low-res
209 animation rig is then attached to these 3 keyframed point
helpers, and well, the 209 moves! The basis for this idea
is from Andy Murdock, creator of Lots
of Robots!
Matchmoving
The matchmove was solved as a nodal pan. Although the camera
was handheld, and the nodal point of the camera off, the perspective
that was in the scene wasn't sufficient to solve it as a free
motion shot. I'd to add and tweak about with the trackers,
but finally came away with a good track :)
Effects - Environmental Lighting
When the 209 fires its gunpods and gets hit by the enemy blasts,
the live plates are lit by faked lighting. For the gunpods'
firing, they were hand painted photoshop glows, overlaid in
post, and had the curves adjusted for a more orange-y glow.
This could be done because they were only "on" for
about 1 frame per burst.
When the 209 gets hit by the energy beam,
the effect was realized by lighting mattes generated from
max. An omni/point light throws light on a white "ground"
object, which is subsequently used as a matte in post. More
on this in the compositing section!
Effects - Enemy Blast
Originally designed to be a cylinder of sorts, I decided to
test some particle effects to act as the beam, and it came
out just as I wanted it! It is kind of a cheat, using facing
particles mapped with a circular opacity map. Kinda like what
is used in video games.
Effects - Energy Shield
For the energy shield I took reference from Gundam Evolve,
Fantastic 4 and finally Star Trek. I wanted a shield that
totally surrounds the 209, but only the area that gets hit
will appear.
The shield itself is made out of several
layers, one of which is just a simple sphere with two UVW
maps, one to handle the shield's "look", and another
to handle the transparency as it fades from opaque (point
of hit) to totally transparent.
Another layer, which is also another sphere,
has a video post lighting effects on it for some electricity
"tendrils".
Finally, at the point of impact, are a series of hemispheres,
for a more concentrated glow.
Compositing
I'll be showing two separate composited stills, first up is
a normal gun blast! On the left is the layer to be added,
and the right is the layer composited in.
First up with have the 209. Rendered without an alpha
channel. The blue tint was from the HDR lighting -
bit too much blue :P
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Color corrected to match the background.
Erm no BG here, but I think you get the idea.
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Here we have the reflection pass...
And several mattes. These mattes allow
me to control the strength of the reflection in each
area.
Cockpit Matte controls intensity of cockpit's reflection.
Ok so there isn't really a cockpit but you get the
idea :)
This matte pass is for the hydraulics.
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This is the alpha channel's matte...
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And wham! Neatly separate, ready to be placed.
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Live plate.
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And the 209 placed neatly on it!
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Shadow matte pass
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And the shadows. They're very faint, you'll see why
soon!
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Gun Lighting comp. Basically, it is to determine
which areas on the 209 gets lit when the guns fire.
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The gun lighting comp is then used as a matte on
an orange-y layer, and these two layers are then added
on top of the 209's comp.
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Gunbursts! These are real gunbursts shot on MiniDV
from Detonationfilms.
A big thanks to them!!!
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Composited!
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Yet another matte. This was to add a bit of specular
reflections to the cockpit.
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It's a very subtle thing...
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Erg. It's just a very faint splotch - more visible
in action. Next on, lighting the ground!
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This is one of the handpainted lighting effects.
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This is why the shadows above were very light - they
are lit by this faux lighting. But this lighting is
also very intense, abeit very short in duration, so...
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A seperate pass for the harsher shadows generated
by the guns firing...
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And the final composite. Also, in order to blend
the 209 into the background, a Mosiac filter was run
on the 209's comps. This gives the edges a jagged
look.
If not, the 209 will look very sharp, while the surroundings
are somewhat blurred, and gives the impression of
miniature photography.
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Some overall tweaks to make the colors more punchy.
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And that's it for the first compositing.
Next up we look at the compositing with the shields,
beams etc.
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We start with the basic elements all
composited.
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Enemy laser blast! Or particle beam. Even Death Ray.
Your choice :)
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Composited!
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This is the hit area, but kinda looks like... mush.
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Thankfully it looks much better after being added
to the composite! This is two layers of the hit area
layered upon each other.
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Electrical Fuzz layer.
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Composited. Doubtful if it can be seen at low res....
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Energy shield layer
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And composited.
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The interaction of energies between a beam weapon
and shield releases some energy in the form of light,
illuminating our dear 209....
This matte above is for the additional light spilled
from the interaction area onto the 209.
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And composited.
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Shockwaves! This is used as a displacement pass.
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This is the displacement pass together with a spherize
filter. Let's look at the faux lighting next...
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The lighting matte. Just an omni/point light at the
point of impact....
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Layered in below the 209.
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Once again, for harsher shadows, a seperate pass.
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And here we have the harsher shadows layered in!
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Once again, bumping up the colors so they are punchier!
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Well that's it for this shot! I hope you find it
interesting and useful!
Alvin
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