Shaping the Ships

To Megatherion · Post by **To Megatherion** » Mon Jul 17, 2006 11:09 am

Hello!
I always marvel at your fantasy in creating new ships. But there's a problem: most designs do look great, but I don't see any purpose beyond style.
Since they're space ships they don't need to be aerodynamically shaped. Of course they land on the occasional Planet now and then, but I guess friction can be reduced somewhat by aptly shaped shields.
So, actually there's no need to go for sleek, jetlike figthers and so on.
So IMO (and not only MO) the shape to go for would be the sphere, which of course doesn't look as nice as all those very aesthetic ships in VS (Tesla looks great, Schroedinger is cool etc.) and an assemblance of differently big spheres would make the game a bit boring, but still, since things like the problems of radiating off the heat in the cold yet not so cold vacuum of space, EMP torpedo specifications etc. I think some thought should be given to this.
There are some advantages the spherical shape has.
The ratio volume to surface is ideal: there's lots of room for cargo (relatively, of course size does matter) and equipment, yet the surface (= the area that can be affected by enemy fire) is quite small. Smaller surface would technically also mean that the shield would be stronger than the one of a ship with comparable volume but bigger surface (when using the same shield system).
Spheres are quite agile when it comes to rotation, so even for one with a mass equal to mule or ox you wouldn't need the turn jet enhancer to rotate. Inertia of course stays the same, so you won't be able to fly narrow curves at high speed with a spherical ship. But the ability to turn in a short time can be vital in combat, unless you rely on your turrets.
Sphere's don't have those fiddly bits that somehow look like wings (Goddard, Schroedinger, Taizong, Shizu,...) which would be quite vulnerable to G-forces when ac-/decelerating, flying curves or when being fired at. Of course a ship like for example the Schroedinger has the advantage that it is harder to hit from behind or front. But space is 3D (well, actually 4D) so you can also attack from above and below (or sheldon slide to the side or wait until the opponent turns and shows it's side, bottom or top).
So I wonder if someone could make a "round" ship. To give you an idea take a look at: http://www.perry-rhodan.net/information ... rajan.html

Oblivion · Post by **Oblivion** » Mon Jul 17, 2006 12:18 pm

Don't worry, I've got spherical and oddly-shaped ships on my sights.

Sphericals in particular for mechanist small ships. Not totally round though. But I'll put it off until I get more experience with textures.

regarding style:

take a look at the new ship. The "wings" are not for flying. They in fact shelter the guns to be nestled between them.

The Cockpit is well situated off the main body but still within the general shield parameters to ensure higher probability of survival in autotomous ejection on engine explosions.

Two slanting shield generators protect the fragile main hull, and can act as armor upon shield failure.

Likewise the bottom box contains projectile weapons - missiles. Hence held away from the body. On event of the armored launcher being penetrated and it explodes, there's a higher chance of the ship still surviving.

As for the general shape. I think wings are really meant to slim down the profile of the ship while still retaining enough space to hold equipment. Of course, a winged ship that is difficult to hit frontwise and backwise, is easier to hit edgewise. Again, look at the wip model of the medium fighter.

Ships seldom gain sight of a ship edgewise, so it is more advantageous to be more difficult to hit when you are facing the enemy or when he is pursuing you. A spherical ship will offer better armor, I think, at the risk of a higher surface area for gunsights.

Think of it:

Which is easier to hit? (if I'm following an enemy):

that:
+++
+++++
++++++
+++++
+++

or that:

+++++++++++
+++
+

rigelan · Post by **rigelan** » Mon Jul 17, 2006 11:27 pm

The shape of the vessel also changes the ability of that vessel to rotate along certain axes. I don't actually know if vegastrike actually takes that into account.

If a vessel is longer, i.e. more mass from the center of mass, it is more difficult to turn that point of the ship. This can allow the thrusters to remain on the approprate side of the vessel. Like the US space shutte. It takes much less effort to rotate it as it does to flip it end over end.

Shapes allow a certain stability of movement.

Ryder P. Moses · Post by **Ryder P. Moses** » Mon Jul 17, 2006 11:36 pm

Spherical designs are nice in theory, impractical in, well, practice. A rocket is not a floating ball of water.

One thing that is overdone which could be jettisoned without uglying up the game too much or making all concepts look like pure foggy theory pieces unladen by history or human design styles is the tendency to design spaceships like airplanes, however. The generally accepted ideal layout for a space vehicle is a tower; down is not perpendicular to the angle of thrust, down is behind the ship, and everything should ideally counterbalance on the central point of thrust.

The whole 'down is back' thing can lead to some difficulty when designing fighter ships, since conventionally they're just fighter jets in space (hence also the unnecessary and generally silly-looking wings- handwave away all you like, unless your vehicle is built for trans-atmospheric flight they're an atavism first and anything else second, not that anachronism is necessarily undesirable in a far-future context), with cockpits for the pilot, and flying a high-speed vehicle while craning your neck to look straight up through glass at where you're going is kinda, well... but the added complication could lead to some more innovative designs.

Post by **loki1950** » Tue Jul 18, 2006 12:49 am

been a while Ryder welcome back

time to beat back the weeds

Enjoy the Choice

charlieg · Post by **charlieg** » Tue Jul 18, 2006 1:03 am

[quote="Oblivion"Which is easier to hit? (if I'm following an enemy):[/quote]
I think you meant:

Code: Select all

that:
            +++
           +++++
          +++++++
           +++++
            +++

or that:

      +++++++++++
          +++
           +

teliot · Post by **teliot** » Tue Jul 18, 2006 3:48 am

i read about somthing called solar winds... although im sure VegaStrike dosent enclude that it may play a part in stearing in outer space. Wikipedia has a nice artical on it

Zeog · Post by **Zeog** » Tue Jul 18, 2006 9:09 am

rigelan wrote:The shape of the vessel also changes the ability of that vessel to rotate along certain axes. I don't actually know if vegastrike actually takes that into account.

It uses a moment of inertia but only one and not three which makes every ship effectively behave as a ball or cube when turning. Different moments of inertia along different axes would certainly make use of piloting skills as it might be easier to first roll and then turn down instead of just turning left.

Post by **klauss** » Tue Jul 18, 2006 3:04 pm

I thought that was already modelled through maximum angular acceleration

Post by **loki1950** » Tue Jul 18, 2006 4:14 pm

teliot solar wind effects depend on surface area and most ships just are not big enough for there to be any effect you need a sail that is kilometers square.

Enjoy the Choice

Ryder P. Moses · Post by **Ryder P. Moses** » Tue Jul 18, 2006 6:36 pm

You've got to admit, though, a sailship with selectively reflective sheets thousands of miles across would look pretty damn cool in a game, tho'.

Post by **loki1950** » Tue Jul 18, 2006 9:39 pm

but how to rig that sail so that you can tack into the wind is a real problem. some early scifi used solar sails but most glossed over the rigging systems i wonder if chuck would cosider them for his mod wasn't there a proof of concept experment a few years ago.

Enjoy the Choice

Paslowo · Post by **Paslowo** » Tue Jul 18, 2006 9:54 pm

I don't know if this fits in this thread but, since you mentioned VS ships need to have more different design to it, I am currently working on a set of ships that have a sligh box look to it.

http://edice.arvixe.com/images/fictspaceships/set1/
http://vegastrike.sourceforge.net/forum ... php?t=7125

Oblivion · Post by **Oblivion** » Wed Jul 19, 2006 3:49 am

Ryder:

You've got to admit, though, a sailship with selectively reflective sheets thousands of miles across would look pretty damn cool in a game, tho'.

Yep.

I loved Treasure Planet's ships. Even if they are soooo unrealistic. But they sure were cool. And of course, I've always like the Rlaan ships.

So, if you people don't mind, I think I'll try to make a ship that will be inspired by lateen-sailed ships of the past eras. Not as solar sails though. Probably shield generator surfaces, and will hold some maneauvering thrusters.

@charlieg
Thanks. Yep that's what I meant.

And space offers no surface resistance whatsoever, so a ball and a winged atavism will still roar around on the same speeds. That's simplifies spaceship design to two reasons:

1.Aesthetic
2.Equipment/Hold Area location and distribution

So why shouldn't designers splurge on wings wings and wings?

... or claws? tentacles? bubbles on stalks? spines? all good to me!

One thing that is overdone which could be jettisoned without uglying up the game too much or making all concepts look like pure foggy theory pieces unladen by history or human design styles is the tendency to design spaceships like airplanes, however.

Anachronisms are cool. hehe

I'm taking the direction opposite to where Paslowo is going. I'm planning to make ships that have lots of jutting parts and/or weird designs. Lots of inspiration too - spiders, sailboats, cellphones, dragonflies, half-eaten donuts

Oblivion · Post by **Oblivion** » Wed Jul 19, 2006 4:03 am

Take a look at Eve Online's ships. They look vaguely organic, and are not airplane-shaped at all.

me likesss thems. my preciousss!

pincushionman · Post by **pincushionman** » Wed Jul 19, 2006 4:34 am

Zeog wrote:
rigelan wrote:The shape of the vessel also changes the ability of that vessel to rotate along certain axes. I don't actually know if vegastrike actually takes that into account.
It uses a moment of inertia but only one and not three which makes every ship effectively behave as a ball or cube when turning. Different moments of inertia along different axes would certainly make use of piloting skills as it might be easier to first roll and then turn down instead of just turning left.

Not three. Nine. Er, six, I believe. Mass effects are most completely modeled by a 3x3 matrix (the inertia matrix, or mass matrix, simply enough), but it's symmetric about the main diagonal, so you only have six unique values.

The three values on the diagonal are your "moments of inertia" that most people are aware of; the other six values are "products of inertia" and are nonzero when you've defined your axes in different directions from the so-called "principal axes" defined by the mass distribution. That is, if you have complex or nonsymmetric geometry (good chance of that in a ship), you've got a good chance of seeing these values. And their presence can lead to some unexpected results if they're not taken into account.

Zeog · Post by **Zeog** » Wed Jul 19, 2006 9:24 am

Ideed, if you diagonalize the matrix, you're left with three and possibly a different set of pricipal axes. I was assuming that most ships are not that asymmetrical and therefore -- as an approximation and to keep the number of matrix multiplications low -- three values sufficed.

@klauss: Actually, I don't what the code does. I just looked at what data is given to it and missed the angular accelleration. If so, what does the moment of inertia do and does the amount of cargo carried have an effect on turning?

To Megatherion · Post by **To Megatherion** » Wed Jul 19, 2006 10:00 am

A problem with solar sails, as far as I see it, is that you cannot use them to sail against the wind...I guess. I might be wrong. Dunno.

Oblivion · Post by **Oblivion** » Wed Jul 19, 2006 11:25 am

No. Solar "Sails" are not used for sailing AT ALL. They are energy gatherers. Exactly like solar panels. And they do look gorgeous on otherwise drab ships.

Post by **loki1950** » Wed Jul 19, 2006 2:38 pm

Oblivion they can be used for sailing but since the force is so small in magnitude you need very large sails for any effect.

Enjoy the Choice

Post by **klauss** » Wed Jul 19, 2006 4:36 pm

Aparently, the moment of inertia has no effect on maneuvering, only on collisions. Though the thing plays a role in the entire system, it gets eventually cancelled out while maneuvering - the point is that, while maneuvering, one's angular acceleration is governed by the corresponding entries and nothing else.

There's something wrong, though... why doesn't the mass have an effect on turning?
Hm...

BTW: Don't underestimate dragging in space. Take a look: the air's density is about 47 MOL/mÂ³, at sea level. That is about 123205 x 10Â²Âº times the interstellar medium's density (in this corner of the universe). Things change drastically within nebulae.
Lets not oversimplify and say that, hence, you need to go 123205 x 10Â²Âº times faster than in the earth's atmosephere to meet similar resistance. Relativistic mass on the ISM grows as you approach c, so if you were to travel at 280000kps, the interstellar medium would already be a noteworthy breeze.
Remember that sails are usually used in generational ships, which tend to accelerate half of the way, making such velocities... thinkable, if not likely.

Post by **jackS** » Wed Jul 19, 2006 6:41 pm

klauss wrote:Aparently, the moment of inertia has no effect on maneuvering, only on collisions. Though the thing plays a role in the entire system, it gets eventually cancelled out while maneuvering - the point is that, while maneuvering, one's angular acceleration is governed by the corresponding entries and nothing else.

There's something wrong, though... why doesn't the mass have an effect on turning?
Hm...

... Are you sure? I'll have to go take a look at the code when I get home from work today...

I'm fairly certain that moment of inertia isn't taken into account during collisions, nor is angular velocity (only mass and the velocity vector of the central point of the object) and thus collisions never produce spin-inducing torque, nor can you meaningfully swat anything by spinning a ship (hence, collisions could use some additional modeling). I was fairly certain that moment of inertia was/is used in determining the resultant angular velocity changes due forces applied when maneuvering. I'll certainly check on this - this would be news to several (although, stranger things have, on occasion, been seen in the codebase

) - however, as we only have a single "moment of inertia" which the dataset currently always sets equal to the mass (I'm reminded of a joke about physicists where the punchline is "assume a spherical cow, homogenously filled with milk....") one could argue that however it's implemented, angular changes are, at the least, underdeveloped... Form-based differences in maneuvering accels can therefore only be currently achieved only through setting the six directional maneuvering thrust ratings... but I honestly haven't looked though that code much, nor for some time. The different manuever rate governor caps.. well... they aren't really an answer to much, at base level, except insofar as they can be used to maintain playability (out of control maneuvering based on acceleration into an arbitrarily fast spin is... not really that fun, especially in larger vessels )

:-/

rigelan · Post by **rigelan** » Wed Jul 19, 2006 9:53 pm

Of course, except for the slower spinning due to cargo mass gained, thrusters could just be designed with appropriate ratios of power to make piloting completely account for the differences in moment of inertia.

Post by **loki1950** » Wed Jul 19, 2006 10:47 pm

not the thusters themselves but the control software.

Enjoy the Choice

Sunfire · Post by **Sunfire** » Thu Jul 20, 2006 1:54 am

@Oblivion: theoretically solar sails treat the solar wind like a parachute interacts with the air. energy generation would be secondary... and the area of the sail would have to be HUGE (hope for no micrometeorites)

@TO you are right... there is no possible medium of resistance against the solar wind... aka a sailboat needs a keel to track upwind (interestingly you also cannot sail faster than the solar wind because you have no resistance medium whereas ships on the sea CAN sail faster than the wind) again... making it not truely a sail but more like a solar parachute..

you also have the problem of the solar wind getting weaker and weaker the farther you get from the sun... but you do have the cumulative effect of mostly massless particles hitting the sail at a very high speed and no resistance contrary... so therefore free acceleration till you reach terminal velocity

so in theory, by the time you get way far away from the sun, you should be going quite fast... and hopefully your solar sail has had the ability to collect and store ions... because then you could fold up the sail and switch to your ion drive... by the time you get to the next star system, (that you would have had to aimed for when you left the sun with a high degree of accuracy) youd use the solar sail to slow you down...