Amiga Computing - Commodore Is Awesome

number of times the 3D
modelling beginner will finish a
0 complex either you object nor that I could has count taken the
many hours of work, then scratch his or her
head and say 'y'know. it doesn't look quite
right.* The problem is usually one of overall
proportion and shape, and even a very
carefully constructed model can be ruined by
subtle inaccuracies.
Keeping a model in tune with the real
world object or design you've based it on rs a
lot easier than you might think, arid as long
as you have a hand scanner or digitiser you
should never have to resort to guesswork.
Unless you have a photographic memory and
artistic skills to match designing an object off
the top of your head only works with
completely fictitious shapes such as
spaceships
Even in this area. though, starting with a
set of blueprints is preferable to jumping in
with both feet. Creating plans for an object in
advance is the best way to decide exactly
what shape it will take, how complex it needs
to be and whether it looks any good to
begin with
If you draw these blueprints on paper,
they can be scanned in, and if you create
them in Dpaint just save them to disk as an
IFF. Plans for real-world objects can be
scanned from photographs or grabbed from
video using one of the many low-cost video
grabbers such as Vtab or Vali Amiga. and
once on disk they can be used as a cheat's
shortcut to accurate modelling.
We'll look at Imagine 3.0 and Ughtwave
for examples of how this can be done. but
the technique used by both programs is very
similar. On Ughtwave, use Layout to load the
various scans, grabs or &wirings you've
created, then go to the display options panel
in modeller to se( the background image on
the X. V. or Z axes.
Imagine users can select a backdrop image
from the View menu and it will appear in
whichever of the three views was last active.
Oraitised iMIMIPS aren't always easy to
on a Oaaaltrois, but Dpaint can be
used to clean thorn up if need be
The games industry have made 'rotoscoping into a buzzword and
given the technique a high-tecri image it doesn't deserve. It is one of
trie most basic cheating methods you'll ever see, and anyone with a
digitiser can do it with ease.
Just take a video tape of a person doing whatever it is you want to
recreate on screen - walking, running, jumping, kicking a ball. serving
in terms. and so on - then grab a number of frames from the complete
action sequence. These can then be used as backdrops to ensure your
human model is put into the correct postures at the correct ome, and
•
Getting the
pkture
StPUIP liennedg PliaMill25 a 5iITIOIP Wag to MaliP
reall5tic model5 a5 a 5 13o55ib1e and
without the aid of an enen51UP 30 digiti5er
Of the two packages. Imagine works with
backdrop more accurately because it
automatically retains pixel aspect ratios, but
Ughlwave users can edit the image's
dimensions to compensate if the picture
comes in looking a little stretched.
For an example, I've used an American
jeep modelled in Lightwave. though the
same process could easily be used in
Imagine. First, a search through my Old
videos produced a tape of A Bridge Too F.
which is ideal because there are zillions of
jeeps in the movie.
GRAB ADD SAVE
Next. VLab was used to grab a shipload of
images from some of the jeep-laden scenes,
the images then saved to hard drive as basic
16-colour greyscale IFFs. After all, you don't
need to bother with huge 24-bit scans and
grabs if all you want is an outline to follow
Some of the grabs were taken with tracing in
mind, and I took care to capture frames
when the camera was looking directly at a
jeep's front or side views.
Other images were taken with jeeps in
different positions, distances from the
camera. arid So on to be used as reference
It an image isn't a clean. side-on Wow,
you'll fume to componsais for the
anglo at which you hese to trace
Rotoscoping is easy
your finished animation will look as lifelike as Flashback ever did
If you have a hand scanner but no digiuser you can look in kbranes
for books that include sequenced images of people or animals in action
ltry the photography and natural history secbons), or just pause your
VCR at the same points you'd normally grab a frame and trace a
iratcnsbck outline of the position of the persons hmbs Use these as a
guide or scan in your matchstick drawings and use them as IFF
backdrops,
Accuracy is always wont the effort
The whole grabbing process took about 30
minutes, leaving me with a much better
idea of what a jeep looked like, arid some
very useful images.
You'd get much the same result with one
• trrz • = •
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Imagine users can US4 the backdrop option
on the latest versions of the program, if you
want to use this, you'll need the upgrade
Amiga Computing
MAY 1995
at I
Amiga 3D Part 2
Ti,. fi nished
model benefi ts becausie
It M accurate enough for the
right effi rci without having to be perfect
of tnose illustrated books that always end up
in remainder bins or bargain bookshops.
Find one with lots of pictures of the sort of
vehicles or aircraft you want to model, then
keep it by your side and scan in any side-on
images for direct tracing.
Not found in remainder bins, but worth
their price to any modeller, are the Janes
series of reference works. These, in common
with the Observer seines, usually have A
photograpn and side, front and top
elevations shown in wireframe. They mioh•
have been designed for 3D modellers, and
just one book can contain outlines for
dozens of aircraft, ships, or vehrcles
• Plastic model kits are another source of
good blueprints, and they have the bonus
that you can build the model to keep as a30
reference. With a cheap greystale hand
scanner, you /I have as accurate a template as
you can wish for In only a few mmutes
Whatever your chosen method, capturing
and using good images of the obiect vou are
trying to model makes for the best start in any
project. If something doesn't look quite right
your finished image or animation can ho
ruined by something as simple as the •ivrteeis
looking a NI too large - hardly the residt
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