Spinning plasma pistol

Posted August 16th 2014

Associated movies… BCM112

This article is going to be a bit odd-out in my fun section because it concerns a freaky phenomenon I can't actually give you a sure-fire recipe for setting up - or not yet anyway. However, if you're lucky you might encounter something like this in some level, and in that case my description here could be useful in helping you have fun with it. At any rate, I thought it was worth writing an article about this, rather than trying to cover things in the commentary for my associated movie BCM112.

Something odd going on here!

The story

This all started in March 2014 when I was attempting a kill 'em all run on Legendary with an AR and rocket launcher and no vehicles - a difficult but enjoyably interesting challenge. After passing through the cavern and dealing with most of the covies in the subsequent tunnel (there was just a Jackal left), I backtracked for supplies and discovered something odd; a plasma pistol grinding on a Shade barrel.

Grinding is what I call it when a weapon gets slowed up from settling, making a characteristic loud grinding noise as it struggles against the scenery or whatever - usually a sloping surface. If you've played plenty of Halo you've likely noticed it at some point, because it's not that uncommon. This particular case was very unusual however, for two reasons. Firstly, I can't recall ever seeing a weapon grinding on a turret before, or indeed on anything except scenery. And secondly, it was going on and on, whereas grinding normally only lasts a few seconds.

Evidently it was the gunner's weapon. I must've killed him with AR fire and the weapon landed on the barrel and started grinding. At the time I never noticed. But now on my return, it caught my attention - perhaps while I was checking that area for dropped plasma grenades.

Whoa! The spin changes!

I probably ended up dislodging it - I forget exactly what I did - but I had a checkpoint to revert to. I'd got one in the tunnel after killing all but the last Jackal; it was delayed from triggering the dropship. I saved it to keep this unusual phenomenon safe. I could return to the cavern any time to see it. My plan at that time was simply to record some footage to make a nice clip for one of my 'freakiness and fun' movies. A clip in which I'd take a good look at the plasma pistol from various viewpoints. I recorded a couple of clips but thought maybe I could do better later when I had more time.

Almost six months later, I got back to this with the intention of getting a definitive viewing clip so I could delete the save to make room on my somewhat congested Xbox (I normally have close to the maximum 99 permitted Halo saves on it). I got a nice clip, but then I happened to try shooting at the pistol. And wow - the changes in spin were both unexpected and fascinating! It quickly became clear that I could make a whole movie out of this freaky pistol. So that became my new plan - and the viewing clip I'd got became the opener for BCM112.

I think it was lucky that I didn't spot the grinding when initially passing through the cavern, else I may've lost it (i.e. if I caused it to end and hadn't had a checkpoint since it started). It was also quite lucky that I backtracked. If I hadn't, I would've missed out on all the fun I've had with this!

Activation line across hump, backtracking to the cavern

Activation zone and grinding volume

In my early times with the plasma pistol, there was something I noticed. Sometimes the grinding noise was at a much lower volume than what I knew it could be. Not satisfactory at all. I thought it was something to do with how I set things up with a further checkpoint, but it remained a mystery until part way through my work on BCM112 when I finally took the time to investigate. I can now give some explanation.

Heading back to the cavern from the tunnel, the pistol is initially frozen in time, so to speak. It's too remote for the game to be bothering to evolve it. That's how the game works I believe; areas effectively freeze when you're sufficiently remote from them. Just after the loading point in the tunnel, there's a hump. By the time you reach the end of that hump, you'll have crossed the activation line for the pistol (and, I expect, everything else in the cavern). Based on my testing, the line goes diagonally across the hump. The near end is about halfway up the rise on the right, and the far end is about halfway down the fall on the left; and the middle is approximately in the centre of the hump's peak. See the picture for an approximate depiction.

Once I'm in the activation zone, the pistol is grinding, even if not yet seen or heard. However, the volume when standing right next to it is initially low, giving a very muted effect as if hearing the grinding through earplugs. Over the course of around 130 seconds from activation, it gradually rises to a noisy maximum. So, the times when I found the grinding to be oddly quiet were simply times when the pistol hadn't evolved for long enough.

Opposite activation line

As for the reason why the volume changes, let's bear in mind that the noise is something to do with how the pistol is interacting with the turret. If that interaction is changing - which is something suggested by the fact that the pistol eventually flies off - then perhaps the noise is changing accordingly. That said, I've looked at the pistol with a zoomed sniper rifle at point-blank range and it doesn't seem to be making any sort of progression, so it's hard to see why the volume would increase so much, or even change at all. So maybe that theory is wrong. Another possible explanation is that the rise merely stems from some quirk in the game's sound handling, but I just don't know.

The activation zone extends into the tunnel on the other side of the cavern. The boundary seems to be a diagonal line across the second hump, very much like what I found for the other side. See the second picture.

The clicking sound

Along with the deep grinding noise there's a clicking sound, reminiscent of the sound you get when taking hold of a plasma pistol. In my 25 fps PAL game there's a click every 11 frames (0.44 seconds), except that occasionally there's a bit of a hiccup (for example caused by multiple needles, as seen in BCM112's second needler clip). Intriguingly, if you pause the game within earshot of the clicking, the clicking is gone when you resume. However, if you then leave the earshot area, the clicking will start up again if you return.

There it goes, right on time

Eventual settling

Left alone the pistol looks to be repeating the same rotation endlessly. However, it's not endless. After about 278.5 seconds of grinding, the pistol will get loose and fly off. Each time, it settles in the exact same spot with the exact same orientation (as far as I've seen). There's a clip in BCM112 which illustrates this predictability. Just before it's due to get free, I move to its settling spot to watch it arrive.

There's no significance to the figure of around 278.5 though. When I killed the gunner, the pistol would've been grinding for some while before I left the activation zone, freezing the situation. If you add that to the 278.5, you'd get the total grinding time. Must be at least five minutes, even if the gunner was almost the last covie I killed in the cavern. I'm sure he wasn't the last, as there's a Grunt beyond who was surely killed later (he'd been sleeping in a remote spot).

Getting a handier checkpoint

For making my movie clips I wanted a handier checkpoint. Fortunately that was no problem. Just near the other side of the cavern I could trigger a tunnel checkpoint and delay it to get it where desired, near the Shade. I did that in various ways, for various things. During the making of BCM112 I sometimes had to fiddle around with the set-up work to try and get maximum grinding volume, which I always wanted. The apparent fickleness was quite a pain. However, that was before I understood what was going on. Now that I know (as detailed above), all I need to do is make sure enough time has passed before getting my checkpoint.

Oops! Clumsy me

Dislodging the pistol

Various things can dislodge the pistol. Whacking the Shade will do it for starters. Likewise nudging the Shade with a vehicle, even if only slightly. Boarding the Shade will do it too. Combining those three things then, it seems that any barrel movement will dislodge the pistol - as you'd expect. Of course, an explosion would do it too.

Then there's the business of cyborgs trampling around on top of the Shade (see pic). If you get near enough to the pistol it's liable to dislodge, and may bounce against you (I think it initially heads in its usual direction). In one sense the pistol seems delicately balanced, because it can fly off even if you think you're merely getting near without seeming to touch it. However, sometimes it initially stays on even if you've stepped close - though it may later dislodge as you move away. So dislodging can be fickle. Maybe it depends on the orientation of the pistol at the time of your approach, but I'm not sure.

Let's get this thing strobing

Spinny fun

The real fun of this plasma pistol is that you can get it spinning in all sorts of ways by shooting it - which fortunately doesn't cause dislodging. In particular you can enjoy getting dramatic strobing effects as seen in BCM112.

To alter the spin you can use any weapon except a rocket launcher. I don't think there's any difference in effect between the weapons, but the AR stands out as being the best overall. When the plasma pistol is spinning fast it can be hard to score a hit on it with most weapons; but with the AR you're able to fire a rapid burst, which raises your chances considerably.

Oooh… spinny needles!

The plasma rifle and needler can fire bursts too of course, but they're not so good. Both of them have a much lower rate of fire and run out of ammo quickly - and the needler is a bit of a pain to keep reloading. Speaking of the needler though, that does have a unique aspect of attraction. Needles can stick into the pistol and look pretty as they briefly spin around before expiring. I'm glad I realized that before I finished my movie!

Originally when playing about with shooting, I was mainly using a pistol. But the AR can fire individual shots too, and as long as you're close, its relatively low accuracy isn't much of a drawback. Plus, you get a lot of shots before needing to reload, unlike the pistol.

You can get a good close view of the spinning by perching on the Shade in various ways, sometimes crouching. In particular you can get excellent close views on either side by standing on the edge of its base.

Note: Shooting it seems to make no difference in regard to the pistol working itself free. It will still still fly off at the usual time and - as far as I can tell - with the same trajectory. However, when it hits the ground it's likely to be in a different orientation than if it had been left alone, and will consequently bounce differently, causing it to end up in a slightly different spot.

Direct hit! Do I win a prize?

Mid-air sniping

Another recreation I enjoyed with my spinning pistol was to blast it into the air with a plasma grenade beneath the Shade, then try to hit it with a zoomed sniper rifle. With light-amplification switched on, the view of the pistol is rather pretty in the darkness of the cavern. You can see me score a hit near the end of BCM112. That particular hit altered the spin of the pistol, but quite often there's no obvious change to the spin.

Actually it was also quite good fun sniping the plasma pistol while it was still grinding. It can be quite a challenge to score hits when it's spinning at a fair speed. Good timing is an important aspect.

Getting your own unusual grinding situation

In the introduction I mentioned that I can't give you a sure-fire recipe for setting up this bit of fun. However, there are two fairly obvious ideas you could try.

Idea 1: Arrange a situation in which you've just had a checkpoint (probably delayed specially) and you're ready to non-explosively kill a Shade gunner (who's the only foe around, ideally). You can repeatedly try it, hoping that his weapon will start grinding on the barrel. I haven't tried this yet and I have no idea what the odds of success might be, but I'll probably try it later.

Idea 2: Arrange a situation in which you've just had a checkpoint and you're ready to drop your current weapon onto the barrel of a Shade, by swapping for another weapon. You can repeatedly try it, hoping to get some grinding. I've given this a preliminary go and there was no sign of any grinding, but I may return to it another time.

NB: If you ever chance across a weapon grinding in freaky fashion such as in my case, you should quickly ask yourself if you've had a checkpoint since the grinding started. If the answer is yes, you're safe. You can revert to the checkpoint repeatedly to play around, and you can save it for later of course; in fact you'd be well advised to save it without further ado. If the answer is no however, you'd better concentrate on getting a checkpoint quick, bearing in mind that the grinding may only last a certain while. Actually, when I say quick, what I mean more precisely is that you should try to minimize the amount of time the weapon is active (it effectively freezes when you're sufficiently remote from it), so you'll have as much grinding time left as possible after your checkpoint.

Getting some normal grinding

I can at least give you a sure-fire recipe for observing some normal grinding. In the tunnel on either side of the cavern, go to one of the humps and throw a weapon at the wall. It'll often grind on the sloping base - and will sometimes get propelled away at considerable speed. It doesn't seem to work with the sloping bases in the long level sections of tunnel however.