Contents | < Browse | Browse >

===========================================================================
   The Creative Magic of Ron Thornton:  Spacecraft Surfacing Techniques
  Bohus Blahut - Modern Filmmaker                          Bohus@xnet.com
===========================================================================

Part II

In issue #4.04 of Amiga Report we began the review of this two videotape
set.   The first tape: Spacecraft Model Design, is a two hour video
tutorial hosted by Ron Thornton, president emeritus of Foundation Imaging.
This first tape stays primarily in LightWave 3D's modeler, and outlines
techniques in constructing a Babylon 5'esque spaceship.  The tape does an
excellent job of leading the intermediate modeler through steps to get a
render-efficient, yet good looking model.  The tape also sets up video #2
in the series: Spacecraft Surfacing Techniques.  Does tape #2 live up to
the quality of the first offering?

The answer is a resounding "yes".  All that's laudable in the first tape is
in ample measure in tape two.  Thornton uses Photoshop and LightWave on the
PC to create all of the surfaces for the model, but what's important here
is not the software or the platform, but the techniques that he shares.  I
was able to complete the spaceship using a combination of LightWave 3.5 and
4.0 for the Amiga along with ImageFX 2.1 to replace PhotoShop on the video.
I'm fairly adept with both softwares, but for those who aren't, I'll
include some Photoshop to ImageFX jargon conversions in this review.  A
future article may include all of the changes that I made to the video's
techniques to accommodate Amiga users.  I used an '060 DraCo with 32 megs
of RAM to run both softwares at the same time.  (gotta love that
multitasking.)

Included with both tapes is a helpful guide card that lists the topics of
the tape in order along with real-time counter information.  For those of
you using a real-time VCR, simply zero your VCR's counter at the beginning
of the tape, and you'll be able to whiz to specific references according to
the card.  For those of you who lack this VCR feature, it's useful at least
to know what order things go in for when you are scanning through the tape.

As I suggested in my last review, skim the tape first without actually
sitting at a computer.  There are a few occasions where Thornton's
surfacing goes in a specific direction, with no explanation, but is usually
explained a few minutes later on the tape.  To avoid these kinds of
creative surprises, have a good general knowledge of the flow of the tape
before you even warm up the computer. 

There are two major components in any 3D model: the object's geometry, and
the object's surface.  LightWave takes a different approach to surfacing 3D
objects than other major softwares.  Many other pieces of software
incorporate surfacing design into the modeling stage. 

Once you've constructed your wireframe object, you use surface tools in the
software's modeler to apply surface color and texture.  The drawback to
this approach is that often you cannot see how your model will interact
with the lighting in your scene until you actually import the model into
your scene and render.  If there are any modifications, you must bring that
model back into the software's modeler, and go to work.  This also makes it
difficult to get a "feel" of how your models look together in an
environment until you actually bring everything together in the software's
stage layout.

LightWave allows you to apply surfaces in the Layout portion of the
program.   This makes tweaking easier, also allowing you to see more
quickly overall adjustments in the scene's environment.

If you were to look around yourself, you could categorize every surface of
every object that you see (note to Mike Danger: how DO you do it, man?) by
it's color, it's diffuseness (the way that light plays across the surface),
and it's specularity (it's shininess).  There are several parameters to
surfaces, but Thornton uses these three elements alone to get a gritty
"mech" spacecraft look.

At Foundation Imaging, they know the value of being frugal with system
resources.  Though they have replaced their Amiga network with many high
powered PC stations now, there's no reason to be wasteful.  Efficient
models mean more time to experiment and be creative, more time to render
longer and more intricate scenes.  Those of you with '030 machines will
appreciate Thornton's approach to render-friendly modeling. 

Thornton chooses a good order to accomplish tasks in this video, in that he
starts with the most intricate tasks first, to build up the user's
technique.  We spend a good deal of time in the creation of the first
imagemap.  Later elements build on these techniques, and so Thornton makes
the most of our time together by glossing over points that would be
redundant.

Since much of the model is composed of structural primitives (simple shapes
like tubes and cubes), much of our surfacing work will involve creating a
flat image in a paint program, then bringing it into LightWave and wrapping
it around a cylinder or a box.  We start, though, with one particularly
tricky part to surface in this model: the wing section.  This part of the
ship is a metaformed pair of wings and rear fuselage.  Metaforming is a
fantastic modeling tool introduced in LightWave 3.5.  It allows one to take
simple shapes i.e.  a few boxes, and smooth them into organic shapes.
Effectively it's like placing a hard geometric object in a wind tunnel, and
wearing it's edges away. 

While surfacing the wing, I found several flipped polygons in the wing's
modeling.  Polygons, when flipped, don't render correctly, appearing as
holes in the finished product.  I used some techniques that I learned from
the first tape to rectify this problem.  In Modeler, pick a few polygons in
the wing, then click OPTION- SEL CONN [select connected].  The whole wing
section should be highlighted.  Click POLYGON- ALIGN and this will flip all
polygons the same direction.

If you were to create a square shaped mech surface for the wing, it would
get hopelessly distorted when applied to the wing shape (square peg, round
hole, etc.).   This is why Thornton uses the model to determine its
surfacing.  By facing the wing section towards Layout's camera, we can get
a good idea of the wing shape.  Also, be setting the Camera's zoom factor
to a huge 70, we can see the model with no perspective distortion.  We
render this out and save to disk, then load up this template into ImageFX.

In the spirit of efficiency, this model doesn't use any 24 bit textures.
It gets its rich look from a pair of 256 grey scale maps, and a four color
image.  Theoretically you could complete this model using an ECS amiga with
Dpaint III, but I wouldn't recommend it.  AGA Dpaint will probably do the
job, but I heartily recommend that you use ImageFX.  Its combination of
image processing, and superlative paint and touchup tools make this
surfacing biz a polygonal piece of cake.  In several ways, I was able to
actually improve on Photoshop's techniques due to dedicated tools in IFX
(Kermit, are you listening?).  In fact many essentials that Thornton
accomplished through multiple menus seemed downright awkward compared to
the few keyboard shortcuts that I used.  Of course, I am much more familiar
with IFX than Pshop, so this may be an unfair comparison.

Once loaded into IFX, we begin by breaking up the wing into squares that
will serve to look like panels.  A point that Thornton stresses is that
many 3D artists just slap panels down anyplace, and that makes their models
look very plastic.  As he stretches the straight line tool, he goes into
some of the reasoning and design behind his choices in panel placement.
Once the wing is divided into logical panels, he uses Contrast and Value
adjustments (like on your TV) to alternately lighten and darken various
panels.  I expanded on this technique by occasionally putting a subtle
gradient in a panel, and also playing around with the ROUGHNESS slider in
all of IFX's paint tools.  This gave the effect of a mottled panel that
perhaps had been replaced, and was made from different metal than the rest
of the ship. 

Once the panels are divided up, Thornton uses some brushes he created in
Pshop to airbrush streaks of dirt onto the model.  Here's one way to
achieve these streaks in IFX.  Go into a blank buffer in IFX.  Load one of
IFX's included brushes into the buffer as a picture.  Let's use the
soccerball (football for you purists) as an example.   You'll note that
it's a little greyscale picture on a black background. 

Now load up a picture of some kind, and load the soccerball as a brush
using BRUSH- LOAD BRUSH.  Click in the picture somewhere.  You get a
stamped version of the picture that you saw earlier, a soccerball on a
field of black.  Now choose the AIRBRUSH drawing tool (it looks like a
spraycan), and pick a red out of your palette, and stamp the brush down. 

Now there's a red soccerball in your picture.  Adjust BLEND and ROUGHNESS
sliders and take note of the effects that you get.  Here's how it works:
the greyscale brush acts a sort of alpha channel.  White (RGB 255, 255,
255) areas of the brush receive 100% of the paint color that you've chosen.
As areas of the brush get darker, those areas receive less and less paint,
until you reach black.   Black (RGB 0,0,0) areas receive none of the paint
color and are effectively invisible. 

A clear example of this is the IFX brush "big ball".  This is a circular
gradient that is bright white at the center, and gets darker as it radiates
outward.  This is the basis of the IFX technique for making streaks. 

In PALETTE, create a grey scale palette that starts at white and SPREADS to
black.   How many steps this range should be depend on how subtle you want
the steps between colors to be.  I found that around 8 steps was
sufficient.  Highlight one end of this color spread, and with the RANGE
cycle gadget set to R1, click RANGE then click the other end of your color
spread.  You'll see little pips appear in the colors in your range, and now
this particular color spread has the identity: R1.

Double click on the corner of the CIRCLE TOOL that contains the FILLED
CIRCLE.   This accesses every draw tool's options.  In the TYPE: gadget
select GRADIENT fill, and if it's not already selected, choose R1 as the
range to use.  If you make a long thin circle, you'll see the outline of
the circle, and a line attached to the pointer.   You can imagine your
cursor as having the leftmost color of your range attached to it.  (Many
users mistakenly believe that the lightest color is always assigned to this
gradient placement selector.  Calling it a 'hotspot' indicator is a
misnomer.) The palette "reads" from left to right, and so colors in a
spread that are to the left are "first".  In our case, we have white
attached to our cursor.  In this scenario, your mouse click will be the
point of purest white.  Other colors in your range will radiate out from
your click point until you reach black. 

In a smallish buffer (I used a black buffer that was 30 x 10 pixels) create
a long thin circle that stretches off of your buffer, so you have the
bottom half of this thin circle on your buffer.  Click the cursor at the
top of this half circle, and you'll have a gradient that is white at the
top and fades to black as it stretches to the bottom. 

Make several of these in various thicknesses and lengths.  Again, you may
want to experiment with various settings in the ROUGHness slider.  Crop
these little buffers close to the streaks without actually chopping into
the detail that you're creating.   Pick them up using the scissors tool,
and save them as brushes using the BRUSHES- SAVE AS BRUSH menu item.  If
you skim the tape, you'll notice that Thornton uses a big blob (similar to
the "big ball" brush mentioned earlier) to depict engine dirt on the wing
section of the craft.  I used a combination of "big ball" with a blob that
I made, combined with the included brushes "sponge" and "smoke".

Once you've created these dirt streak brushes, apply then with the
airbrush, and a black palette color.  I also recommend that you turn the
BLEND slider in the AIRBRUSH options (double click spraycan) down to
between 20 and 40%.  This allows you to have subtle variation with the same
brush through multiple clicks.   Load your streak brushes into IFX using
BRUSH- LOAD NEW BRUSH and choose between them using BRUSH- SELECT BRUSH. 

You can use Thornton's technique of selecting regions on your wing section,
then airbrushing dirt onto these stenciled off areas by doing the
following.  In your region selector, choose whatever type of region you
intend on using i.e.  BOX and select a region in your picture.  In REGION
OPTIONS check off "ENABLE PAINTING", and paint away.  In order to choose
your next region, you must go back into REGION OPTIONS and disable "ENABLE
PAINTING" before moving on.   This range selection- masking- painting-
process will grow into an efficient routine that will become second nature
by the time you've finished this tape. 

Another time and labor saving technique is to work on only half of the
texture map, then mirror it where it is symmetrical.  It obviously depends
on your needs, but for most people, the repetition in the pattern will
hardly be noticeable while the model is in motion.  One could also mirror
the partially finished panels, then work on each side individually to yield
at least some time savings.  Once you have your greyscale paneling and
dirtying down finished, you'll save this as you diffusion map.  This tells
LightWave how light will play across your model.  Darker grey areas will
appear to be darker in color and so on. 

One could place this greyscale picture directly onto the model, but by
having the map reside in the diffuse channel, this means that you can
choose any color or combination of colors for the surface color, and still
retain all of the detail of the specular map.  Thornton takes advantage of
this to add some pinstriping to our model.  Another advantage is that if
you want a whole fleet of these ships, you can have a single diffuse map
loaded into LightWave's memory, but have several different 4-color maps
applied to the various ships in the scene to offer a sense of variety.

The Diffuse Map also acts as a guideline for the Specularity Map.  Thornton
shows you how to take the Diffuse Map and heavily contrast it to yield the
Specular.   LightWave's Specular channel allows you to load an image map
onto a model that controls how shiny a model will be.  Brighter panels will
be shiny while the dark dirt streaks will be matte.  Thornton even goes
through including little white dots throughout the model that will appear
as very shiny.  Though almost imperceptible to the eye, the mind will pick
up on these little flecks of shininess as parts of the ship that have
little dings and dents and flecks of paint missing.

Once you've completed the wing's surfacing, you have the knowledge of the
techniques to finish the rest of the model.  Thornton makes rather short
work of the rest of the model.  It'll still take the modeler some time to
create all of the image maps featured rather quickly in the rest of the
video.  Not to worry, Thornton does give the viewer intermediate screen
shots of his work, along with periodic color renders, so that the viewer
can follow along. 

Once finished with the custom image mapping, the rest of the task is left
up to the LightWave modeler's best friend, Fractal Noise.  This creates the
overall metallic grit on the rest of the model fairly quickly.  Though only
a 90 minute tape, these techniques will make good on the viewer's in-depth
investment of time.  Though I'd set aside a morning to follow these
techniques, I spent the better part of a day exploring these methods in
other types of modeling.

Again Desktop Images delivers a fantastic instructional tape at a knockout
price.   I'm only sorry that it's over.  I'd love to see a tape that dealt
purely with the basic aesthetics and design topics only touched upon
briefly by Thornton in these tapes.   Other good topics, especially if one
could get more presenters of the calibre of Ron Thornton, would be 3D
cinematography, effective lighting, special effects, and perhaps more
intermediate modeling that isn't targeted specifically toward making
spaceships.

This is a hearty recommendation to the modeler looking to increase his
professional and personal modeling to get these tapes now.  As I mentioned
last time, I'll post a picture of the completed model on the Web.  I don't
intend to release my LightWave model of the ship because I think that the
LightWave community would benefit greatly from every modeler making their
own version of this ship.  Instead of littering AmiNet with multiple copies
of the same ship, let's try to create new and exciting models using these
techniques and share those instead.   I can hardly wait to see the first
non-spaceship non-submarine application of some of these techniques.