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Does anyone have a great texture for starship hull plating? Especially
grittyness. My pathetic attempts all look weird. Please help.
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Albert Sacks wrote:
>
> Does anyone have a great texture for starship hull plating? Especially
> grittyness. My pathetic attempts all look weird. Please help.
Attached are a couple i have often thought would work well for
bump mapping the hull of a space bound ship. If you do a little
work colorizing them they might also be usefull tiled with a small
scale on the hull of a ship. I just never got around to trying them
but they are yours if you want them.
--
Ken Tyler
mailto://tylereng@pacbell.net
Post a reply to this message
Attachments:
Download 'shiptex.gif' (6 KB)
Download 'shptex.gif' (5 KB)
Preview of image 'shiptex.gif'
Preview of image 'shptex.gif'
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You're right, there are some very interesting issues here. No way is it easy
to write something that looks good, and doesn't take FOREVER to get results.
The way I see it there are at least three issues.
1) You are right, if his variable "Time" was the total
time, he would be in real trouble.
The variable "Time" isn't the total time, it's the
time between frames. So, if this time is SMALL ENOUGH,
the acceleration is pretty much constant, so the
program IS right.
The real problem was with defining the units correctly.
( i.e. he had accidentally defined the gravitational to
be WAY too strong )
2) The other issue is the issue of realism. In a lot of
particle simulations, you don't really care if the
simulation cheats a bit on the physics. You just
want it to look GOOD. But Peter wants to simulate
something real, and something we all know. So if he
runs the simulation and Mercury falls into the Sun
he's in trouble!
That depends something called the "numerical stability"
of the simulation program. It depends a little bit on
the exact method you use to estimate the new positions and
new velocities, but it mostly depends on the amount of
time between steps.
In this case, I got pretty good results for 1 frame =
3 days, or "clock_delta" = .01 which you get in a 100
frame animation.
One really cool way to check this out is to run the
simulation forward 100 or 1000 steps and then run it
backward by the same number of steps and see if you
get your original data back.
3) This is definitely not the most efficient way of doing
things! You could probably make something that looks pretty
good without solving ANY differential equations. The
orbits of almost all the planets and moons in the
Solar System are pretty circular, which means that they
travel in circles about the body they orbit at a constant
angular velocity {i.e. the earth has an angular velocity
of about 1 degree/day = (360 degrees / 365.24 days) and the
moon has an angular velocity of about 360/28 degree/day
around the earth.}
This method looks good, and is less prone to the
difficulties listed in point 2.
Actually computing the paths of the planets this way
is really only good if you want to see the TINY effect
that the Sun has on the orbit of the Moon, or the REALLY
TINY effect that all the other planets have on the orbit
of Mercury.
With even 10 objects the rendering time is so much longer
than the computation time that it just doesn't matter, but
I wonder what happens when you start tossing in all those
moons and a few asteroids ...
This really is a cool topic. Maybe we could start a thread on simulation
issues or something!
Until that Day,
Ben
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Here you go, I have found this one very usefull, works well as a bump map as
well.
Rick
Albert Sacks <asa### [at] mindspring com> wrote in message
news:3730BDDB.BD906EBA@mindspring.com...
>
>
> Does anyone have a great texture for starship hull plating? Especially
> grittyness. My pathetic attempts all look weird. Please help.
>
Post a reply to this message
Attachments:
Download 'GenericPanels.zip' (135 KB)
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You know, I can really appreciate this kind of "deck plating". I think it's
the streaking and rust that makes it look so GOOD. But then I ask myself "how
would a ship get that rusty in space, and why would it streak?"
By the way, how'd you do it?
Until that Day,
Ben
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Ben Birdsey wrote:
>
> You know, I can really appreciate this kind of "deck plating". I think it's
> the streaking and rust that makes it look so GOOD. But then I ask myself "how
> would a ship get that rusty in space, and why would it streak?"
Well speaking of a purely hypothetical situation it might be possible that
the fuel used in the ship is one of the severe oxidizers like most of the
fuels used in the US space program. Additionally it is common, at least with
current technologies, for fuel systems to leak until a certain quantity of
fuel is loaded thus forcing the seals to seat which halts further leakage.
Until this happens the severe oxidizing agents are exersizing their unique
ability to create surface oxidation reduction reactions on the exposed metals
of the space vehicle accelerating the decay and shortening the life span of
of it's outer metallic surface.
A severe oxidizing agent needs no atmosphere to create a reaction so this
explains the oxidizing even in a vacuum. The streaking is from where the
fuel is accelerated along the surface of the ship as it is docked to a
revolving space port and eventually boils off into space. But before this
happens it has already had time to inflict it's share of damage.
This is all of course conjecture on my part and is not based on any first
hand observations. As soon as I do get the opportunity to make observations
of this type I will forward them to you in a timely manner with any comments
I think may offer you greater insight into this seemingly unsolvable mystery.
--
Ken Tyler
mailto://tylereng@pacbell.net
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Of course, it could be that most space faring vessels of in science fiction are
able to spend some time "on the dirt", so they might have the same problem as my
car: too much salt and not enough detergent!
Anyway, my original comment was meant as a bit of good natured fun. Why put
oil tanker crud (rust) on a "space tug", when it really needs "space tug" crud?
I mean, who knows what these ships are made out of? They might be impervious to
chemical attack. The discoloration might come from an EXOTIC source like high
energy particles from its "reactor", solar wind, or ion storms. Or maybe its
something more interesting like accumulated re-entry crud or (God help us) space
barnacles!
But it's cool to realize how powerful a touch of the ordinary can make
something exotic seem so much more REAL. Why else did Mr. Lucas ask his prop
guys to make the props for the new Star Wars movie from everyday stuff? And if
you look back even further, most ancient depictions of monsters, demons, and
other scary creatures have familiar animal or human features. (I'm talking
about creatures that look like a demented surgeon cut two things apart and sewed
them back together again: a man's head on a lion, a hawk's head on a man, a
woman with a fish tail, people extra mouth on their stomach.) That might not
sound too real to us, but in their day people believed that the sphinx, Ra,
mermaids, or some demon really existed, and really looked like that!
Until that Day,
Ben
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The other reason for starship hull streaks would be minute particles of
dust wearing down the plate... assuming no force fields?
Ken wrote:
>
> Ben Birdsey wrote:
> >
> > You know, I can really appreciate this kind of "deck plating". I think
it's
> > the streaking and rust that makes it look so GOOD. But then I ask myself "how
> > would a ship get that rusty in space, and why would it streak?"
>
> Well speaking of a purely hypothetical situation it might be possible that
> the fuel used in the ship is one of the severe oxidizers like most of the
> fuels used in the US space program. Additionally it is common, at least with
> current technologies, for fuel systems to leak until a certain quantity of
> fuel is loaded thus forcing the seals to seat which halts further leakage.
> Until this happens the severe oxidizing agents are exersizing their unique
> ability to create surface oxidation reduction reactions on the exposed metals
> of the space vehicle accelerating the decay and shortening the life span of
> of it's outer metallic surface.
> A severe oxidizing agent needs no atmosphere to create a reaction so this
> explains the oxidizing even in a vacuum. The streaking is from where the
> fuel is accelerated along the surface of the ship as it is docked to a
> revolving space port and eventually boils off into space. But before this
> happens it has already had time to inflict it's share of damage.
> This is all of course conjecture on my part and is not based on any first
> hand observations. As soon as I do get the opportunity to make observations
> of this type I will forward them to you in a timely manner with any comments
> I think may offer you greater insight into this seemingly unsolvable mystery.
>
> --
> Ken Tyler
>
> mailto://tylereng@pacbell.net
--
The individual is more important then the state!
Politicians are lying, cheating, thieving, underhanded, corrupt,
unethical, unprincipled, degraded, venal, money-grabbing,
self-serving filth that should be killed on sight
(in the messiest, most painful way possible)!
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Thanks a lot! I really don't know how I made this mistake as I got
evey piece of data out of handbooks and references etc. and converted
it to SI units. Anyway, now that it works, I will continue my project.
The Solar system model was just a check to see if this thing would
ever work, and it does, thanks to you. I'll start throwing in more
complex stuff now :)
---------
Peter Popov
ICQ: 15002700
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On Wed, 05 May 1999 17:04:41 -0500, Ben Birdsey
<bbi### [at] unlgrad1unledu> wrote:
<snip>
> 2) The other issue is the issue of realism. In a lot of
> particle simulations, you don't really care if the
> simulation cheats a bit on the physics. You just
> want it to look GOOD. But Peter wants to simulate
> something real, and something we all know. So if he
> runs the simulation and Mercury falls into the Sun
> he's in trouble!
I will actually model a twin star planetary system. I am planning to
use a particle system to illustrate how a black hole "sucks mass" from
a star that passes nearby. I will also, do a particle system with
collision detection in addition to gravitational forces, and have some
laugh watching rubber stars knock each other in space. Last thing I am
planning is to put a camera on the moon, point it at Earth, and do a
dizzling roller-coaster-style animation that will make you all sick
for a month :)
<snip>
> Actually computing the paths of the planets this way
> is really only good if you want to see the TINY effect
> that the Sun has on the orbit of the Moon, or the REALLY
> TINY effect that all the other planets have on the orbit
> of Mercury.
How about Charon's effect on Pluto?
> With even 10 objects the rendering time is so much longer
> than the computation time that it just doesn't matter, but
> I wonder what happens when you start tossing in all those
> moons and a few asteroids ...
NumCalcs = NumObj^2. I might get along with 100, maybe even 250
objects. More will be overkill.
>
> This really is a cool topic. Maybe we could start a thread on simulation
>issues or something!
>
> Until that Day,
> Ben
All the best,
---------
Peter Popov
ICQ: 15002700
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