Main Battle Tank Gun Ballistics, FCS, etc.

[4 IN 1 0]

ARGH!

When I was trying to test the APFSDS mode, I found out that I've got 2.5 km cull distance in ArmA, beyond which NOTHING is displayed except land.  I could very clearly see my target disappear into nothingness as I tracked him, and I couldn't see my shell impacts at 3 km.  At least the rangefinder still works.

Is there any way to fix this?  Or is it tied to my view distance somehow?

Better news, however, is that I could consistently get a third-shot hit on a moving Abrams at 2.3 km.  That's about what was expected of Soviet tankers, and the reason they started equipping tanks with ATGM.  

Also, I've modified T-72 and M1A1 turrets to their real traverse and elevation rates.  The M1A1 turret is only a little bit slower than the default, but the T-72 turret is SO SLOW, you'll instantly get pissed off if you try to rotate 360 degrees with the mouse.  You'll get even more pissed off if you try to change the gun elevation...at all.  It's about as fast in powered mode as the M1A1 gun is in hand-cranked mode.  Another reason to get a joystick (or bind keys to "aim up/down/left/right"), I guess.  The joystick will only give you full traverse rate if you're zoomed out to 1x magnification, but that's an option I've provided.

You can still track a target with the mouse, and I used the mouse in those screenshots above (too hard to use the joystick and push PrtScn at the same time).  You just won't be able to effectively scan for targets with the mouse.  It is also very hard to keep the reticle on center mass of a moving target for 1.5 seconds while using a mouse, and there's nothing I can do about that.

erm....................by having/ finding someone who have a very very very powerful PC

[NonWonderDog 0]

Ok, I've figured it out. Objects disappear at 5/8 view distance when using 6x optics. Why they aren't displayed further out when using optics, I don't know. I just overreacted at the 2500m thing, as it seemed way too specific (exactly 2500m, not 2510, not 2490) to be a coincidence. Back to testing...

Now if only they weren't completely oblivious to me brewing them up at 3km distance...

[4 IN 1 0]

i have my sceneComplexity=500000.000000 in the .ArmAProfile at My Documents\ArmA Other Profiles\username

is this the case?

[mechastalin 0]

Object detail also influences it.

And I didn't know the old T-72 turret was that slow, but I guess it was designed to compete with the older Pattons and such thats why.

[NonWonderDog 0]

T-72A:

350 mils/second traverse (18 seconds for full revolution)

60 mils/second elevation

M1A1:

750 mils/second traverse (8.5 seconds for full revolution)

450 mils/second elevation

The default ArmA traverse and elevation rates were 1200 mils/second for everything.

The T-72A numbers are directly from my Soviet operations manual, so they should be accurate. The M1A1 numbers are the currently unclassified specs, so they might be a bit low. (The M1 with its 105mm gun might have been faster, but I still think the exaggerated claims of a 6-second traverse time are just wild.)

It's not a small difference, and the T-72 absolutely can't spin its turret fast enough to engage close-in targets. That traverse rate is the absolute maximum, too, and it can only spin at that rate in real life if you pull the gun up to max elevation.

"As slow as the hand crank in an M1A1" is a bit of an exaggeration, but 3.5 degrees per second is not a fast elevation rate.

[mechastalin 0]

T-72A:

350 mils/second traverse (18 seconds for full revolution)

60 mils/second elevation

M1A1:

750 mils/second traverse (8.4 seconds for full revolution)

450 mils/second elevation

The default ArmA traverse and elevation rates were 1200 mils/second for everything.

The T-72A numbers are directly from my Soviet operations manual, so they should be accurate. The M1A1 numbers are the currently unclassified specs, so they might be a bit low. (The M1 with its 105mm gun might have been faster, but I still think the exaggerated claims of a 6-second traverse time are just wild.)

It's not a small difference, and the T-72 absolutely can't spin its turret fast enough to engage close-in targets. That traverse rate is the absolute maximum, too, and it can only spin at that rate in real life if you pull the gun up to max elevation.

"As slow as the hand crank in an M1A1" is a bit of an exaggeration, but 3.5 degrees per second is not a fast elevation rate.

The Russian manual may be in Russian mils, which are only 3000 units. Still pretty slow compared to M1A1 though.

[NonWonderDog 0]

It was in degrees. Don't worry, I'm aware of the difference between NATO mils (6400/rev) and Russian mils (6000/rev). I've programmed them in as milliradians, though, just because it was easier.

[mechastalin 0]

Oh okay, didn't know the T-72 was so slow. Although its probably more a case of the M1A1/T-80 being faster.

[NonWonderDog 0]

It's very slow. That 300-350 mils/second number is for spin mode, too. The fastest controlled traverse rate of a T-72A's turret is only 100 mils/second. It's actually slow enough to be limiting, as it prevents you from engaging close-in fast-moving targets. Or helicopters.

I think the joystick traverse rate in ArmA is about 1/3 the defined speed (i.e. 100 mils/second) at 6x magnification, but I don't think I computed the exact number. That won't stop me from claiming to have "simulated" the difference between aimed traverse (zoom in) and spin traverse (zoom out).

You can always move at 350 mils/second with the mouse, but only in bursts (obviously).

[mechastalin 0]

Was the turret sped up in later models?

[Panda-PL- 0]

Was the turret sped up in later models?

Are there any later models at all?

The urban legend is that the export T72s are WORSE than russian ones, not better.

I also don't know why T80 would be any faster. It's basically the same platform (T80 was supposed to be an assult tank, heavier and more bulky tank designed to break trougth NATO lines, it is not far better than T72 and probably not half as good as T90).

As to the spinner problem: AFAIK you cannot directly acces the proxy. You could rotate it but only if you'd add it to tank model.

Afaik reticle models are not animated at all.

Placing the spinner in front of player is a good solution, remember to use local spawning and check if gunner(mytank)==Player and stop the script from running on server to keep multiplayer compatibility (which is perfectly possible, as proven by tracers).

BTW: tracers have quite tight loops and run alot but cause no FPS drop of any kind, you could take a look inside the Six_tracers if you'd like to check how it's been done.

The loop doesn't have to be that tight either, you can add setvelocity together with setpos and suddenly the object moves much smoother.

Just my 0.02$.

[mechastalin 0]

@ Oct. 02 2007,09:34)]

Was the turret sped up in later models?

Are there any later models at all?

The urban legend is that the export T72s are WORSE than russian ones, not better.

I also don't know why T80 would be any faster. It's basically the same platform (T80 was supposed to be an assult tank, heavier and more bulky tank designed to break trougth NATO lines, it is not far better than T72 and probably not half as good as T90).

As to the spinner problem: AFAIK you cannot directly acces the proxy. You could rotate it but only if you'd add it to tank model.

Afaik reticle models are not animated at all.

Placing the spinner in front of player is a good solution, remember to use local spawning and check if gunner(mytank)==Player and stop the script from running on server to keep multiplayer compatibility (which is perfectly possible, as proven by tracers).

BTW: tracers have quite tight loops and run alot but cause no FPS drop of any kind, you could take a look inside the Six_tracers if you'd like to check how it's been done.

The loop doesn't have to be that tight either, you can add setvelocity together with setpos and suddenly the object moves much smoother.

Just my 0.02$.

No Urban Legend, export T-72s are far far worse.

And T-80 is very different, it is an evolution of the much more advanced T-64 platform which is superior to T-72 which was cheaper counterpart to T-64.

[Gedis 0]

ok, just to clear things out...

T-64 was the first of this endless design yet...

the first tank in the world with autoloader

the first tank in the world with smoothbore 125mm gun

the first tank in the world with 2 cycles turbo diesel engine(don't know exactly, but engine's design was revolutionary or something)

the first tank in the world with such a new and revolutionary(in those days) combined armor with much layers

when T-64 entered service, crews which were operating older tanks, even T-34-85s! were not used to such a revolutionary tank and led to tank's braking. After the training of such a new system begun, problems were solved. But still tank was costly to maintain.

So they decided to build T-72 for warshav's pact nations. T-72 was easier to maintain, was easier to learn, easier to build and was close to T-64's charecteristics. And T-72 could be(and it was/is) exported to the other countries. Leaving the T-64 only for soviet army.

Later, some soviet brains thought an even better tank than T-64...

So the T-80 was born.

It had turbine engine

Better hull and turret armor

ATGM fired from gun

New tracks

New suspension

blah blah blah...

T-72(cheap, simple) and T-80(costy, quality, complex) is not comparable, T-64 and T-80 is.

and now about export versions...

you know how soviets sold tanks? took batalions of T-72s from army, dismantaled some secret/modern stuff, like targeting systems, placed on some old versions of those targeting systems, placed on old ammo, repainted and here you go, you just bought "new, @ss kicking tank" (not new, reduced quality,...)

[NoRailgunner 0]

T-72 (export versions) have basically upgraded engine and an improved Fire Control System. Other stuff you may ask you arms dealer and engineers.

(Polish T-72's had some modernisation using Leopard2 technology)

It would be nice to see the difference between old original T-72 and latest T-72 (with numerous upgrades)! But... who would (long-) play with old T-72.... my suggestion - make the T-72 with modern (upgraded) technology and all (mouse) players are happy too. Maybe you have to write fewer scripts/workarounds.

[NonWonderDog 0]

There most definitely are new models of the T-72. In fact, the bulk of Russia's tank force is comprised of them. The new T-72B(M) models with the thermal sights are probably on par with an old M1 IP.

As to turret traverse, I believe the T-72 and T-64 traverse rates are similar. Scratch what I said here about the T-72S before, the T-72B and T-72S use the 2E42-2 stabilization system instead of 2E28M, which has a 24? degree per second slew rate rather than the 20 degree per second slew rate of the T-72A. It's a little bit faster, then. The T-72B(M) might have a faster turret, but I don't know.

I'm not sure about the T-80 turret. I think the new T-80UM1 turret is (nearly?) as fast as the one on the T-90, but the T-80B turret is slower. The turret on the original T-80 (the one with the coincidence rangefinder) might be every bit as slow as the one on the T-64, but I don't actually have hard data on any of these.

The T-90's turret is very nearly as fast as the one on an Abrams. More generally, there isn't much of any technology gap between a T-90 and an M1A2 (except with regards to survivability--if a T-90 gets penetrated, it will probably explode). The M1A2 SEP is better, but Russia doesn't have the funds to build their new tank designs.

I did find .pdf operations manuals for the T-54 (450 pages!) and T-62 (650 pages!!), but they would take so incredibly long to OCR that it's not worth it. I can't find the manuals for the T-64 and T-80B. I know they were declassified, but they're nowhere to be found. I probably have enough info to make the Russian gunsight used in the T-34-85 though the T-62, though, and I could probably take a good whack at the T-80B gunsight. The T-80U and T-90 use various thermal sights, and I have no clue what the displays look like.

Not that I'll be making these any time soon. Just that, you know, I can. The T-72A/B gunsight I'm making should be more or less applicable to the baseline T-64, T-72, and T-80 tanks, anyway. All of these should use the coincidence rangefinder version of the sight and should lack the lead computer, but I'm almost certain that it will be impossible to simulate a coincidence rangefinder in ArmA.

I still have some FCS work to do, as my code currently ignores own tank speed and trunnion tilt. The latter isn't very important, but the former is critical. Then I just have to get the range spinner working and tweak the ammo damage a bit.

[digitalcenturion 20]

You are insane

Good job! Also, I hate the T72 even more now Btw, what is the difference between the T72A and M1? Is the M1 a export version of the A? I'm starting to understand why finland chose to scrap/mothball their T72M1 fleet in favour of the Leopard 2A4 and T-55 (yep...) fleet.

Speaking of the Leo, how does it compare in turret traverse rate and stuff?

[mechastalin 0]

You are insane

Good job! Also, I hate the T72 even more now Btw, what is the difference between the T72A and M1? Is the M1 a export version of the A? I'm starting to understand why finland chose to scrap/mothball their T72M1 fleet in favour of the Leopard 2A4 and T-55 (yep...) fleet.

Speaking of the Leo, how does it compare in turret traverse rate and stuff?

Early Export Models

# T-72M - Soviet export version, similar to T-72A (built also in Poland and ex-Czechoslovakia).

# T-72M1 - Soviet export version, with thicker armour (built also in Poland and ex-Czechoslovakia).

Early Soviet Models

# T-72A - Added side skirts, additional armour, laser range-finder, electronic fire control system, smoke grenade launchers.

# T-72B - Thicker armour, composite armour in front of turret and front of hull. AT-11 "Svir" laser-guided antitank missile capability.

[NonWonderDog 0]

Adding a floating object with the reticle painted on it doesn't work. I can get it to show up, and I could probably animate it if I set my mind to it, but it lags too far behind where it should be. I can't put it close enough to the the camera to be useful, either, since it seems to avoid the tank model even if it has an empty collision model. (I've been using simulation="thing", is there a better one for this?)

I still don't know how to attach it as a proxy, but proxies can't be directly animated anyway.

I might just make 200 different object definitions with different "up[]" vectors and hide all but one, but that's crap. There really should be a way to rotate a UI object in script.

[EDIT]

It's dumb, but it works. I now have 400 definitions for the range spinner, each with a different up vector, for ranges from zero to 4000 meters in 10 meter increments. The script hides all of them at init, and displays the one it needs. It even uses a loop to make it look like it's spinning (in 0.75 degree ticks). I need to redo the model, though, since a single 1024x1024 texture is clearly too small now that I can get a good look at it. I'm halfway through redoing it with 250 polygons and a 64x64 font texture instead.

[opteryx 1562]

Your efforts and dedication for this project are deeply appreciated NonWonderDog. I only hope there's not too many engine limitations in your way, really hope to see you implement most of your ideas.

[xnodunitx 0]

You are insane

Good job! Also, I hate the T72 even more now Btw, what is the difference between the T72A and M1? Is the M1 a export version of the A? I'm starting to understand why finland chose to scrap/mothball their T72M1 fleet in favour of the Leopard 2A4 and T-55 (yep...) fleet.

Speaking of the Leo, how does it compare in turret traverse rate and stuff?

the M1 and M1A1 are different versions in general, the biggest differences between M1 and A1 is the larger main gun, basket on the back of the turret and a different tread wheel on the far rear. Due to the time I can't remember the exact specifics such as the size differences between the cannons.

http://en.wikipedia.org/wiki/Abrams_tank

also

http://www.fas.org/man/dod-101/sys/land/m1.htm

and

http://www.fprado.com/armorsite/abrams.htm

About the turret rotation speed, there was a segment showing an abrams turret rotation on discovery channels "Build it bigger" . It could get going rather speedily, I cannot say for certain if this is a difference between a A1 and A2 upgrade but I do not recall turret speed being part of the A2's upgrade, I'll look around and if I find it I'll let you know.

[quiet_man 8]

ATGMs will fire just fine out of a tank gun, in case you were wondering, but ArmA's ATGMs don't work past 1500m. This makes them completely useless, of course, since they're designed for 3-4km range. I might try to script my own bar-scan beamrider instead of using ArmA's guided missles, but I don't expect miracles. This would rightly be for a T-72B/T-72S instead of ArmA's T-72A/T-72M/T-72M1/whatever, but I'm not losing sleep over it.

Mandoble?

QuietMan

don't know if this got lost?

using Mandoble rocket script might save you some time.

QuietMan

[NonWonderDog 0]

I think he was talking about the export T-72M1, which is just a T-72A with a TPN-1-49 night sight instead of the TPN-3-49. Other than that I think the A and M1 are pretty much identical. (The T-72M differed in that it had the armor of the baseline T-72, and--other than the night sight--the equipment of the T-72A. The T-72M1M is a 2005 model with Kontakt-5 ERA, thermal optics, a new engine, and various other upgrades. The Polish monkey models were called T-72G.)

The TPD-K1 sight and 1A40 fire computer are now mostly functional, and I'll try to release a beta soonish. I replaced the simple 1D lead extrapolation with 2D positional target tracker code, and the lead computer now works at any speed. The code doesn't cheat at all, and works pretty much exactly like a real FCS. The only things missing from the FCS are trunnion tilt and wind corrections, and wind does not (currently) affect projectiles in ArmA. I think I know what the trunnion tilt corrections are supposed to look like, but I don't actually know how to implement them.

Turret speed is continuously averaged over the last 1.5 seconds and called when needed. This is how it works in the M1A1, but it isn't how it's supposed to work in the T-72. I think it only computes turret speed when the lase button is held down, and freezes the result when you let go (just like in a Leopard...). I have the lase button bound to a keyboard key, but the code doesn't grab the key state yet. I think I know how to do this, but you would never get applied lead if you lase with the action menu.

Anyway, here's my latest testing screenshot. The range spinner spins to whatever range is indicated by the LED display when you lase a target:

http://gallery.filefront.com/NonWonderDog//790245/

(Hmmm... that's supposed to show 18,0 instead of 17,0. Just found a bug, then. And just fixed it.)

Unfortunately the range spinner sits on top of everything else, including the LED range digits. I don't think I can fix this. "Objects" seem to sit on top of "Controls" no matter what, and they both sit on top of GUI elements.

Manual range entry is still on my to-do list.

The laser mark is back to the photo-supported size, even though it is a 2 mil diameter. I think I've come to the conclusion that the laser mounted on the T-72A really is so crappy as to have 2 mil divergence. It only has a maximum range of 3000-4000 meters depending on weather, anyway.

More importantly, the "laser" now fills the entire laser reticle. It works by shooting seven massless bullets at the speed of light and finding the impact range, so the rangefinder is unfortunately uninfluenced by smoke. The rangefinder will return the range to the closest thing in that 2 mil circle, as long as the range is greater than 500 m. (On the real T-72A, that minimum range can be adjusted between 500, 1200, and 1800 m. I still need to implement that.) If the range is less than the defined minimum or greater than 3000-4000 m (depending on the weather ) the digital display will show blank and the gun will battle sight to 800 m.

The reticle isn't illuminated yet. It will be stupid easy to illuminate the reticle itself, but I don't know how I'm going to illuminate the range spinner. I might have to make another model (and another 400 model definitions...) in yellow.

I have yet to adapt this code for the M1A1. I have all the code and graphics I need, but I'll need to rewrite all the FCS code to be continuously computed after you have a range.

I think I can adapt the M1A1 lead into an LCOS sight for the M163 Vulcan ADS, too. I'll just have to figure out how to simulate a ranging radar, since my code already tracks traverse and elevation rates.

I'll look into Mando Missiles, but I've decided not to include the Svir missiles in the first release. The T-72M in the game shouldn't be able to fire them anyway.

[NonWonderDog 0]

New update, and I've got the M1A1 optics mostly functional:

http://gallery.filefront.com/NonWonderDog//797111/

It doesn't really work like the real thing, but it works. In the real thing the gunner's handles move the reticle, and the sights float around to show proper lead. Unless I can find some way to rotate the turret in script, I won't be able to implement that in ArmA. Instead, you move the sights and the reticle floats to show proper lead. It sounds like a small difference, but it's a whole lot slower to use than in the real thing (or Steel Beasts). As with the T-72 optics, it's a lot easier if you have a joystick.

As it is, you have to lase, move the reticle back on target, and reacquire lead for ~1.5 seconds before you can be sure you're firing accurately. It's still a lot faster than the T-72 lead computer, though.

Multiple returns are signified with the bar over the range. By default, it displays the last range returned. I haven't made range logic configurable yet.

The ready light (the little square) works quite well, and will illuminate when your gun is loaded. This works because of another modification I've made to tanks: you will need to manually reload every round. I think this is a lot better anyway, since you can choose what type of round to fire beforehand. Unfortunately, it also means you can unload HEAT and reload APFSDS in the same amount of time it takes to reload after firing. Just ignore this and fire off whatever's in your gun barrel, and you'll be alright.

Fortunately, pressing the "reload" key or button reloads whatever type of round you just fired. You don't actually have to search through the ammo list each time.

I still need to make the laser follow the reticle, but I don't think that will be too hard...

[opteryx 1562]

Can't wait.

By the way, will you be adding any fire commands?

Sabot up!

[ryankaplan 1]

wow, its looking really good.

However, will all this work in multiplayer or will we face problems?

Also, i hope you'll consider releasing some 'realistic' armour values to go with your optics project too.