[Plugin] [Part] [0.17] KIS Connect V7a [2Oct12] [MIT]

[Zhent]

Here are a couple of shots showing what I am experiencing. I will do what I can to try and narrow the issue down, if possible.

First shot: Sitting on runway, Connect attached, everything hunky-dory

Second shot: like 30m in the air, you can see the entire rocket has spun a good 20-30* in the span of almost no time.

[kellven]

Might have something to do with the radial soyuz style engines, I\'ll have to build a similar one, and try it out.

[noneyabidnis]

Something interesting I just found that may help.

I created a rocket that\'s 14 larger stock fuel tanks tall, with a single engine at bottom. Cuttlefish lander at top. When I leave the little black box off the rocket, it at least stands up straight for a while, and then gradually falls over in one piece. When I attach little black box, it breaks apart and falls as soon as I go to the launch screen.

I know the rocket sounds ridiculous, and it won\'t fly, but perhaps the excessive amount of fuel tanks and the exaggerated behavior between black box on the ship and black box not on ship will help the problem stand out.

[kellven]

noneyabidnis & Zhent, were you both by chance using Satellite Relay Network?

I noticed the GUI from the screenshot. I have a vague notion that the course shift might possibly be caused by my destroying the stack nodes when replacing them. I\'m thinking that might cause some parts to get sent a message that makes them think they were 'forcibly disconnected' from the main ship.

I\'ll rewrite the plugin now with the new PartModule system, and try to replace the stack joints before I destroy the old ones, and see if I can replicate the course 'correction' north with the sat plugin running.

I noticed when analyzing the new plugin system that I can catch when the joints need to be replaced much easier under it. Unfortunately, that looks to be the only easy part of the system.

[kellven]

I finally saw the problem myself. Yay me! I can think of a couple explanations, but it doesn\'t seem to be directly related to the sat stuff in any way. I didn\'t actually launch the ship, as it was dancing a pretty pirouette around the pad without any help from me, but I think I understand what\'s going on, maybe...

Running the plugin in the new PartModule system I think should fix or eliminate one possible cause. Setting up the spring node like I said I was going to should eliminate another.

[kellven]

Persistence of non-default types is still completely fubar for me, so cfg settable soft joint limits are out. The workflow and even overridden method invocation are quickly unraveling with this module.

In human speak, don\'t be expecting a new version today, the new plugin system is about as sturdy as the joints this thing is supposed to replace.

[Zhent]

I will try a different bottom to the rocket tonight and see if that sorts some of the issue out. Unrelated to the rotation I\'m having trouble keeping my rocket from tipping around, I think I need more SAS or something, so time to re-engineer

[kellven]

Sorry this is taking so long, but I\'m fairly certain the new plugin system is broken with non-basic type persistence, which I actually have to workaround to get a fix for this to work.

Here\'s what I *think* the problem was, at least the one I saw.

1. The new model system ends up with tighter collision boxes, and the collision handling itself was set to be 'harder'.

2. In the 0.14x version, the joints being 'tightened' didn\'t have noticeable effect on this because the rest of the system was so loose to begin with. Which is why wobblyness caused such severe problems.

3. With the new 'tightened' collision, added to the 'tightening' of the joints I introduced, what we have now is an 'echoing cascade of near perfectly elastic collisions'. In human speech, we went from dropping a quarter on a pile of laundry to dropping a quarter on an army bunk in basic training. When the joints are tightened by this plugin, it becomes dropping a quarter on a sheet of tool steel.

4. This shows up as the rocket dancing merrily about the launchpad when it\'s dropped to ground after reassembly from the VAB transition. In big rockets, might just disassemble instead.

5. Why North? I have absolutely no idea, but I think it\'s just physX\'s underwear peeking out. Probably related to the rotation you get whenever you stick too many radial engines on a large mass ship in vacume. The collision echo wouldn\'t just happen on the launchpad, it would also happen inflight, as the new colliders are nudging each other constantly, I think one of the devs said they were having issues with that in 0.15 normally. Most likely, the net vibrations just end up resolving in a shift north for some unknown algorithmic reason.

6. What do you intend to do about it, and why is it taking so blasted long? Re-setup the joint replacer to add a little give in the form of dampening(Like sticking some bubblewrap between the parts so they don\'t bang into each other so hard). It\'s taking forever because I can load the softjointlimit data into the new plugin architecture, but they new system refuses to save that data once it gets it, as it\'s not one of the simple predefined types. I finally have a mostly working custom serializer, but I think I must have screwed up the logic in one of the validators.

[kellven]

Yay, hoo-ray, it\'s finally done. The thing you\'ve all been waiting for is finally here. What does it do? It makes every single part on your ship explode simultaneously!

Seriously though, I finally got this mountain of code 'working', as in fully functional, actually replacing the joints, and making the parts explode.

Here\'s some demonstration screenshots:

This transcript was recovered from the black box:

Jeb: What happen ?

Bob: Somebody set up us the bomb.

Bill: We get signal.

Jeb: What !

Bill: Main screen turn on.

Jeb: It’s you !!

Kellven: How are you gentlemen !!

Kellven: All your joints are belong to us.

Kellven: You are on the way to destruction.

Jeb: What you say !!

Kellven: You have no chance to survive make your time.

Kellven: Ha ha ha ha …

Bill: Jeb !!

Jeb: Take off every ‘ZIG’!!

Jeb: You know what you doing.

Jeb: Move ‘ZIG’.

Jeb: For great justice.

[00:00:00]: Structural failure on linkage between ZIG and FL-T500 Fuel Tank.

ZIG collided with fuelTank - relative velocity: (2.1, -1.8, 5.7)

fuelTank Exploded!! - blast awesomeness: 0.9

Once I figure out how to replace the joints without making the ship explode in 0.15, this should be good to go.

[kellven]

It looks now like the root problem is the terrain collision. I got the new plugin to behave like the old plugin, so it\'s at least where the last version was. By 'loosening the bolt' (projection settings function exactly like a bolt) 0.025 KerbalDimensionUnits, the ballet on the launchpad turns into a jitter and wobble in whatever parts are in contact with the ground.

The behavior also occurs when landed off the pad, so it\'s the terrain collision itself, not the pad surface. The behavior does not manifest in small mass objects, only heavy ones. Once in the air, the problem resolves either way. I believe the turn to north is just the result of an unstable initial launch trajectory, or it may be something else entirely, there\'s so many bugs in the game now it\'s impossible to pick one out individually.

The good news is that by making that 0.025 KDU adjustment, the rocket engines in contact with the pad wobble and slide, but the rocket remains upright, and given time to sort itself out, comes to rest. That exact measurement was the minimum to achieve dynamic stability, and probably varies by total load force on the contact points.

The bad news is that the Unfathomable Mu the Magnificent confirmed my suspicions about object types not persisting, and is working on a bugfix. There\'s actually a ton of data needed to setup a joint right, too much to store it individually, so the cfg settings for softjointlimit data are highly buggy. Once that is fixed, tweaking spring and dampening forces might help make the problem unnoticeable.

The good and bad news is that this is almost ready to be released again in working condition, the remaining problem is that struts seem to instantly snap when replacing the other joints. Once I figure out how to stop that, it should be usable, if still buggy.

[kellven]

Ok, it works reasonably well. Smithers, release the hounds.

[kellven]

Bumpage for 0.17 update

[mnnm1234]

Cool mod will use!