Railgun.oxp v 1.3 now available

[Commander McLane]

This wasn't apparent in the first version of the OXP.

Hypothesis: try it near the witchpoint.

This is the first version of the OXP. The second only exist on my HD till now.

And yes, the rings are an artefact of how the projectiles are spawned (namely just like any ship entity). I didn't consider that this would cause them to get rings if created close the the witchpoint.

I'm working on it, trying to spawn them in a different way.

[Cody]

This is the first version of the OXP.

My mistake... I'm obviously confusing it with another OXP. [wanders off, scratching his head]

[Commander McLane]

Anyway, I've fixed it. Version 1.1 uses spawnOne instead of addShips.

Although I have to say that the effect looks kind of lovely. Could be a residue of the abruptly cut-off immense currents immediately after the projectile is leaving the rails.

[Cody]

Although I have to say that the effect looks kind of lovely.

Yeah, it did look kinda cool.

[Thargoid]

In this case it would come in really handy if there was a JS-way of doing multiple installations, just like for lasers. You choose the equipment first, and then the mount direction. Another post-MSNR request, I guess.

Agreed, it would be nice. Probably a 2.0 request though I guess?

Using the same ammo pool would imply that you can't mount different guns in different views, though. After all they use different ammo. It would be either small, medium or heavy everywhere.

For me it would actually make more sense to have common ammo, as it's just how hard the slug gets chucked (hence both how much damage it does, how much energy it uses and possibly even how far it goes) would really only depend on the gun that's giving it the velocity. After all conceptually the ammo is just a dumb lump of metal?

[Eric Walch]

..... After all conceptually the ammo is just a dumb lump of metal?[/color]

There is a big difference between ammo of different density. When your ammo has a much higher density than the material that is hit, it has a much higher chance of penetrating that target. It has a good reason that depleted uranium is used in high quality bullets. Such bullets have a much higher chance of penetrating a tank than a steel bullet of the same weight and kinetic energy.

[JensAyton]

It has a good reason that depleted uranium is used in high quality bullets. Such bullets have a much higher chance of penetrating a tank than a steel bullet of the same weight and kinetic energy.

It also fractures on impact in such a way that it becomes sharper rather than blunted, and the bits thus shaved off spontaneously catch fire once they reach the inside of the tank, and are also toxic. If density was the only concern, gold would be a better choice (which it wouldn’t be even if it was cheap).

[Spartan]

First off, thanks for this OXP, I happen to like railguns. My actual use was going to be primarily mining, and depending on the damage perhaps for convincing offenders they should eject if the damage was light enough. So I went with the small railgun. I have run into problems, namely it shoots through targets more often than not. I would guess this has to do with the speed of the projectile and game mechanics, I think it is through the target before it is detected as a hit. on large targets I would normally get hits but on small ships or boulders it would just pass through, this was confirmed by using the exterior point of view.

Something I would like to see is the ammunition listed on the Ship's Manifest, such as the chaff remaining is for the Automatic Chaff System by Wyvern. While I'm at it, should the ammo be listed as a separate piece of equipment, so as to be destroyable in combat? At one point I had to launch and fire the railgun for the out of ammo message before I could dock and buy more ammo. I knew I had 0 rounds left but the ammo was still listed on equipment.

Is ship speed added to ammo speed? I once fired while injecting only to hit myself. What is the range on these, and what happens to rounds that miss? Do they have a small charge and a timer for self destruction in case of a miss, for safety?

"In other news today, a large railgun round, apparently fired 187 years ago by carbon dating of the fragments, impacted the yacht of a visiting envoy in the Inera system, killing all aboard. War was immediately declared. Are there more potential killer slugs floating about? Both GalSec and the Navy had no comments."

[Commander McLane]

First off, thanks for this OXP, I happen to like railguns. My actual use was going to be primarily mining, and depending on the damage perhaps for convincing offenders they should eject if the damage was light enough. So I went with the small railgun. I have run into problems, namely it shoots through targets more often than not. I would guess this has to do with the speed of the projectile and game mechanics, I think it is through the target before it is detected as a hit. on large targets I would normally get hits but on small ships or boulders it would just pass through, this was confirmed by using the exterior point of view.

See this post from the thread where the concept was first discussed:

To begin with, I'm working with something considerably smaller than an asteroid. Smaller than a cargopod, actually, roundabout the same size as the basic missile, but with a really high speed. One major problem is that most of the time the projectile flies straight through the target, even if aimed perfectly. Collision detection, again. Which is of course bad for a weapon which deals its damage only through collision.

Something I would like to see is the ammunition listed on the Ship's Manifest, such as the chaff remaining is for the Automatic Chaff System by Wyvern. While I'm at it, should the ammo be listed as a separate piece of equipment, so as to be destroyable in combat? At one point I had to launch and fire the railgun for the out of ammo message before I could dock and buy more ammo. I knew I had 0 rounds left but the ammo was still listed on equipment.

While I'm against cramming too much info on the Manifest screen, it is indeed bad to remove the ammo equipment only when displaying the out of ammo message. This will be rectified, thanks for alerting me.

Is ship speed added to ammo speed? I once fired while injecting only to hit myself.

No, the ship speed is not added. Therefore firing the weapon while on fuel injectors may be a bad idea. To be honest, it never crossed my mind that somebody would want to. Firing while on full speed (without injectors) should be fine, though.

What is the range on these, and what happens to rounds that miss? Do they have a small charge and a timer for self destruction in case of a miss, for safety?

See Wiki and readMe:

Fauchon-Oliphant Inc. guarantee the efficiency of all their projectiles up to a range of 20 km, independent of the type of projectile. Above this range the projectiles tend to dissolve due to the increasing friction with the surrounding phlogiston.

All projectiles are removed after 20000 m. In a vacuum they would of course go on forever (or to be more precise, until they eventually hit something). But as we all know, in Oolite space isn't a vacuum. It is filled with semi-rigid phlogiston, which is the reason why ships need propulsion—resulting in visible exhaust—in order to maintain their speed. The more prosaic game mechanics reason is that the number of entities allowed in a system is limited, and getting closer to this number slows Oolite down. Therefore removing the projectiles after a while is a necessity.

[Spartan]

What, read the instructions?? </grin duck & run>

Something occured to me, what if the projectiles were longer, would that help with collision detection?

Taken to extremes:

"Oh my God, he's fired a telephone pole at us, eject!"

Phlogiston eh, same element group as handwavium? Yeah. I figured that numbers were the reason, I was giving a more technical reason for them to go away I am surprised cargo is not given a time to die, lets face it. If it's 1000Km + from the planet and heading out fast, chances are it will never be discovered by anyone without some kind of long range sensor.

BTW, those rounds are travelling at translight speeds if you think about it. A Cobra III at flank speed pushes .35c if I read things right, 2.45c on injection and 11.2c on Torus! "Cap'n she ken nae take th' strain!"

[Cody]

Phlogiston eh, same element group as handwavium?

Same element group as unobtanium, as well... maybe that's what the slugs should be made from... depleted unobtanium.

Seriously though... McLane, this is a great dog-fighting weapon... it might just make having both NPC Shields and ToughGuys2 installed survivable.

[DaddyHoggy]

What, read the instructions?? </grin duck & run>

Something occured to me, what if the projectiles were longer, would that help with collision detection?

Taken to extremes:

"Oh my God, he's fired a telephone pole at us, eject!"

Phlogiston eh, same element group as handwavium? Yeah. I figured that numbers were the reason, I was giving a more technical reason for them to go away I am surprised cargo is not given a time to die, lets face it. If it's 1000Km + from the planet and heading out fast, chances are it will never be discovered by anyone without some kind of long range sensor.

BTW, those rounds are travelling at translight speeds if you think about it. A Cobra III at flank speed pushes .35c if I read things right, 2.45c on injection and 11.2c on Torus! "Cap'n she ken nae take th' strain!"

c and LM are not the same thing. Think of LM as a marketing ploy, a comparison between ships only not as an actually percentage of the speed of light - as Marks and Spencer's might say: "This isn't just Physics, this is Oolite Physics..."

[Switeck]

Ship speeds as fractions of c might only be correct while using either injection or the torus. So "normal" speeds are only 1/7th or 1/32nd that. I still contend that most everything is magnified by the ship's scanners...and the real distances are in miles not meters. Even still 0.1 LM would mean ~1.87 km/sec.

[Commander McLane]

What, read the instructions?? </grin duck & run>

Something occured to me, what if the projectiles were longer, would that help with collision detection?

Maybe. But then, maybe not. I've managed to fly my Imperial Courier (and a Cobra III before that) straight through a Generation Ship, and all of them are vastly bigger than the projectiles.

Oolite's collision detection simply isn't ideal.

[Eric Walch]

Oolite's collision detection simply isn't ideal.

You can't blame everything on collision detection. This is more a matter of frame rate. Your bullets have a speed of 3000 m/s. With a frame rate of 60 the bullet travels 50 meter between two frames. When the ship is bigger that 50 meters, one of the two frames will always detect the collision. But even a cobra III has a hight of only 30 meters, so shooting it bottom up has a reasonable chance of going through undetected.

And that was with a good frame rate. When the rate goes down to 20 it is already 150 meter displacement between two successive frames. Oolite is just not designed for that speeds. To make it fool proof, it would require to interpolate the last two positions for collision detection. And that is a whole different approach of collision detection and is currently not happening.

There have been reports of pilots flying through rock hermits at torus speed.

Is ship speed added to ammo speed? I once fired while injecting only to hit myself.

No, the ship speed is not added. Therefore firing the weapon while on fuel injectors may be a bad idea. To be honest, it never crossed my mind that somebody would want to. Firing while on full speed (without injectors) should be fine, though.

Is would be no real problem to use "3000 + player.ship.speed" instead of just "3000". It makes the bullets more deadly when shooting at injector speed. (As long as they yount fly through undetected )