Amiga Computing - Commodore Is Awesome

98
GRAPHICS
up electricity for no good reason.
To set up a scene for use with Screamer
Net, the user loads it as usual in Layout,
then brings up the network panel using the
SN button found in later versions of
Lightwave. He or she then has to go
through a ridiculous sequence of initialising
the Alpha chip (fair enough). clicking on
buttons to send the scene, object, and
image data to the Cobra, another to tell it to
load the scene, and a final button to start
rendering.
PREFERED ASPECTS
Separate buttons are available to send
just the object, image or scene data across
in case changes have been made to one of
these since the scene was last sent to
Cobra, but though this is useful, a batch
render option would have been much more
welcome. With the machinery and software
at your disposal when using Lightwave on
the Cobra, it's very frustrating not to be
able to give the beast a long list of scenes
and tell it not to bother you until it has finished
them. ARexx scripts could be used to
automate things. so why didn't NewTek
take this option?
A second complaint is the amount of
time the Cobra chip sits idle, even dunng
rendering, while the data is passed
between the two machines and written to
disk on the Amiga. For some reason. the
Screamer Net programmers have made it
possible to link up to huge machines with
super-fast chips, massive hard drives, and
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Keeping up with
the big boo
1, The Screamer Net
process begins with a click
on the Ind button, which
instructs the Amiga to
search for available
processors on the
ethernet connection
2. Nest, the user uses this
bank of buttons to send a
Scene and its objects and
images to the Cobra. This
takes less than a minute for
most scenes
of c
In lull operation the Cobra is about 20 times faster than
the 68040-based A4000. though some of the performance
is squandered by the networking software. Our
62 seconds example was based on actual rendering
time Once the PC and Amiga Lightwave programs
had finished shuttling data around and writing it to disk,
this became 111 seconds per frame, a 79 per cent
slow down.
Don't get me wrong - Cobra is one mean piece of
equipment which at the E7,000 price mark blows
Raptor out of the water and leaves all other desktop
power stations for dead (it eats Pentiums for breakfast),
but the fact that it could be a lot faster with more
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A performance monitor
running on the Cobra
under Windows Ni' gives
a graphical display of the
amount of time the Alpha
chip is forced to sit
around and wail. The
yellow line show. prosios.
for activity, which drops
to zero for long periods
between rendering
Screamer ' n i t
Amigo Computing
NIA Y 1995
(tear fi ll Fillies
3. no fi nal panel is used to
load the scene into the
Cobra's remote copy of the
Light
-plus
buttons to begin ren-
wove dering or shut Screamer Net
rdown e
n d
e r i
n
4„
g
Any available processors
eup
to a masimum of eight
nwill
be shown in this win-
gdow
and their status is indi-
isated.
Screamer Net can
nUre.
more than on. type of
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,
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the control panel
processor in two or three
neheorkeri machines
5. The individual buttons tor
sending image and object
likes are useful when you
Franc.
are experimenting with a
scene, and change just a
couple of things before
rendering again
Waiting for CPUs to fi nish rendertng
CPU
2
3
4
5
6
T ype
A
l
p
h
a
Send Alt Fites
Status
Rendering
r an e
Send Object Fties s e n d Image F i j i
---
Cont inue
oodles of RAM, and then make use of all
this hardware only 50 per cent of the time,
For example, the standard Space
Fighters scene from the Lightwave samples
takes between 44 and 70 seconds per
frame when rendered on a 68040 at medium
resolution and no anti-aliasing. The
Cobra is often slower.
Yes, slower. Data can be passed across
ethernet connections at megabytes per
second, but Lightwave takes 40 seconds or
more to grab the rendered data from the
Cobra and write it to disk, during which
time the Alpha chip is doing absolutely
nothing.
STAGE FRIGHT
Lightwave has always been a bit slow off
the mark when it goes into the integrating
pixels' and 'writing RGB data to disk'
stages, but as there's a version of the core
rendering engine on the Cobra and an
awful lot of spare space on its hard drive
and in its 64Mb RAM, you'd think someone
efficient disk writes on the Amiga Lightwave side is
something any prospective owner would find as
frustrating as I did.
Smaller companies and very wealthy freelance
graphic artists, however, will see Cobra as a chance to
join the big leagues without spending hundreds of
thousands of pounds. Indeed, a suitable summary for
this product is that you could buy a complete network
of machines and software for the price of just one
(slower) Silicon Graphics Indigo and one copy of its
superb but ludicrously expensive software.
Think about it. For the cost of a small business loan.
you could be the next industrial Light and Magic.
Aduanc
Last Frame Rendered: 1
Rog Rendering Time: 1 4 2 s
„
IL Frame advance can We
set to manual or 1161161111fint
as in Lightware, bet Ow
independent sotting •WNW
when you have arodalease
processors- AS they sag al
work away on their ease
frames, thus reducing
waiting periods
Independent
would have thought it a good idea to p•
this excess capacity into service
Rendering the frames mentioned above
on , the Cobra takes between three and
seconds (lings!), which makes it all -
more frustrating when the rest of Mir
process makes this up to 45 seconds pa
,frame. Until the basic operation c•
Screamer Net and Lightwave are changed
to make more use of the Alpha chip, the
system as it stands is surprisingly
inefficient.
With more complex frames which
require proper ray tracing or more intensive
calculations, the efficiency of the sys
tern improves, but there's always at least
30 seconds per frame lost, and when yot.
render 300 or more this adds up very
quickly. Having said that, when you watch
a frame which would take the A4000 18
minutes churned out in only 62 seconds by
the Cobra, it's difficult not to step back ir
awe_
17
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1
Eh e bottom lirm
Product: Cobra 275AXP
Supplier: Carrera Inc
Price E7,000 approx
Phone: 0101 714 707 5051
Ease of use
Implementation
Value for money
Overall
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