How big a ship can be made?

[numerobis]

Assemblies make it extra easy to make a ship with a stupid number of parts; I got about 1800, of which about 400 struts. Unfortunately, PhysX can't handle that size of scene, I get a bunch of "unable to create broadphase entity" errors in the KSP.log, along with some errors about overly deep hierarchies.

How big a ship can be built before these errors pop up? I wasn't able to find actual documentation of this error online (just lots of people asking how to avoid it).

Discovered so far:

1. You can go to at least 1500 parts, you can't go to 1800 parts, in the VAB.

2. You can launch 1800 parts.

3. You can dock several thousand parts.

Edited October 27, 2013 by numerobis

[vexx32]

Biggest ships I see that actually work end up being ~800 parts. I rarely see anything bigger than that, unless the person building it has a monster of a machine. It's usually under Linux, too, because they can use the 64-bit executable to give them a bit more leeway.

[AlamoVampire]

this is just my preference, but, I try to stay south of 450 parts but, have gone north of 800 before, all of which causes various amounts of lag lol.

[Galacticruler]

...unless the person building it has a monster of a machine

Wackjob.

TENCHAR

[numerobis]

Yeah, I'm not worried about speed. What I'm worried about is that there is a size of spacecraft where physx starts spitting out errors about being unable to load the entire scene. I would like to have that number of parts, minus one.

If I run at a frame every two seconds, that's fine; not running is not fine.

[zekes]

<Ahem>

Get it here!

http://forum.kerbalspaceprogram.com/threads/51571-LARGEST-ROVER-IN-KSP-EVER%21-P-1000-Ratte-1300-Parts-300-tons-by-Zokesia-Skunkworks%21

[Deathsoul097]

Just going to say this: Look up the Vanguard's final docking on youtube, and prepare to be dumbfounded, amazed, and just downright gob-smacked. I think it ended up at over 4000 parts, and I am guessing it massed about that many Tonnes, too. Just going to say, The Vanguard could probably have had the Delta V to get to and return from every single celestial body and return, looking at the amount of fuel and Nerva's on it.

Sorry Zekes, but I think Christopher Woertz has you beat.

EDIT:

(link to video mentioned in post)

EDIT2: The biggest plane I have ever seen (Again, on youtube) was around about 3000 parts, and I think it was called the Titan MK 4

Link:

Edited October 27, 2013 by Deathsoul097

[numerobis]

<Ahem>

So, 1300 parts works. Can we get more?

[numerobis]

I think it ended up at over 4000 parts

Mass doesn't matter, it's just a number. Where do you see the 4k parts? The link in the youtube description tells me I don't have permission to see it.

[Deathsoul097]

Oh, no my friend who showed me the vid said that, And to be honest, looking at that behemoth of a behemoth, I'd say that sounds about right.

It says the same to me too...

Maybe the thread was deleted... -v()v- (shrug)

Edited October 27, 2013 by Deathsoul097

[Thogapotomus]

There's a welder mod that allows you to combine multiple parts into one new part, thus reducing your overall part count and improving performance. I haven't used it before, but it might be worth checking out if huge ships are your thing.

[allmhuran]

As far as a hard limit goes, once you go over a large number of parts you actually get crashes in the VAB related to the part tree. I can't remember the exact error, it seems to start happen (for me) above around 2000 parts. This one had a few issues with that:

[camulus777]

They should make it just a part of the game. when two parts are combine they become into one and all you have to calculate is stress on general areas of the craft. That whay when the physics are used to calculate all that fun lag causing crap it only has to calculate a fraction of it at once.

[allmhuran]

The problem with that is that it makes rockets of arbitrary size essentially indestructible.

[camulus777]

Not at all, they still break just a easily. We see it all the time. a similar technique was used in the making of force unleashed called intelligent matter. Each bit was made up of many parts that when put together were one whole, but when the physics applied varying degrees of force to parts of the object it would break apart in the appropriate way. Te objects could have small parts broken off, partly broken off, or if enough digital force was applied the object would be blown to bits sending things in every witch direction.

A similar but not exactly the same method. Objects that are linked together will just respond sequentially rather than simultaneously. When enough stress is applied and an item breaks, then the item becomes many and the engine reads them as such but only according to the stress. You will still get flexing but not of every individual bit only of one greater part until it snaps.

It would require fundamentally changing the way the game reads and displays whats going on, but it would be possible to have ships of eminence size flying through space being read as one object with several points of stress till it is broken. Heck the guys at squad are all geniuses and probably have a more practical way of making it so we can use more parts at once, I was merely saying that this is one way it can be done.

Edited October 27, 2013 by camulus777

[allmhuran]

The force applied to a part in KSP is dependent upon the force being applied to other parts "prior" to it with respect to the initial application of force (the engine, drag).

Either

1) Everything is one big piece, in which case no rocket would ever fall apart unless you exceeded the *internal* breaking force of that one big part... which is not a thing that exists. So if you make a whole ship one big part, you can build an arbitrarily large ship and it will never break

Or

2) You have multiple parts and calculate the stresses as they propagate through the tree, which is the expensive part of physics computation, and is what KSP does now.

[700NitroXpress]

3564 parts shown all together in this station.

1100 parts in this station. This is Big H.O.S.S. Helios Orbital Solar Station, under it is a bunch of Ion engines so it basically has an infinite fuel supply as long as there is gas for the ion engines.

In theory, I could doc both of these stations together and have a super station, but I haven't tried it... yet.

[Moar Boosters]

I've found strange things start happening at a similar limit to you guys. Usually between 1700-2000.

Sometimes parts in the VAB become unselectable. They'll still be there, and will work during launch..... but in the VAB you can't make them green by mousing over them, and you can't attach new parts to them or set action groups for them.

At that number of parts the struts start bugging out too sometimes. Both ends will look like they're connected, but there actual strut in the middle will be missing.

This is about 1800 parts and started bugging out.

It still works though.

[numerobis]

"It still works" -- hmm, maybe I should have tried then. As you say, the struts and fuel lines visually were all messed up in the VAB, but I didn't even try to launch.

3500 parts in orbit, and struts work. So, maybe the VAB has a smaller limit? That, or the limit isn't the number of parts per se, but the number of parts in a single tree of parts (ie one vessel, whereas the result of docking is multiple vessels docked together)?

[700NitroXpress]

"It still works" -- hmm, maybe I should have tried then. As you say, the struts and fuel lines visually were all messed up in the VAB, but I didn't even try to launch.

3500 parts in orbit, and struts work. So, maybe the VAB has a smaller limit? That, or the limit isn't the number of parts per se, but the number of parts in a single tree of parts (ie one vessel, whereas the result of docking is multiple vessels docked together)?

The part limit in the VAB is different than the part limit that your system can render and run on screen. So if you have several ships that are 1500 parts, you could launch them all and dock them in orbit and assemble massive vessels that otherwise wouldn't work as one in the VAB.

This is also going to take a monster machine to run. I have an intel quad core clocked at 4.0 ghz 32gb of RAM and a EVGA GTX 690 and I'm getting about 10 fps on both station pictures that I posted.

[Moar Boosters]

Yeah, I expect docked vehicles are treated differently. The other day I was playing and my game was running extremely slowly during my launches. After a few launches I realized it was because I'd left a 1000 part spaceplane on the runway, so the game was loading that along with my 1500+ rockets. Nothing was bugging out there it was just running slowly, so I expect you're right about the single tree thing.

[700NitroXpress]

One possibility as to why this works the way it does, is because the game is saving two ships to memory in the VAB. You have the ship that you're building and then you have an equal auto-saved ship that the game is saving for you in case of a crash. While both are being stored together in active memory, it can run slowly. While the ship is in the game and loaded, you're not actively saving the auto-saved ship to memory because the game is only focused on the current ship. Also, unless you are launching you're entire craft into space without staging anything, you're loosing a bunch of parts and once they pass the render threshold of 2.3km they don't have physics loaded anymore so the game will run more smoothly.

[numerobis]

That theory isn't consistent with what we see: when you load a ship in the VAB, it fails to load properly if it has 1800 parts or more, whereas it does load properly with 1500 parts or fewer (and somewhere in between we get problems). So under your theory, there's a 3600-part limit internally. However, when you work on a moderate-sized ship in the VAB, you don't get it bugging out after adding/removing parts four times to a 900-part ship, as your theory would predict; instead, you can work arbitrarily long on that 900-part ship, even though you can undo repeatedly.

[DaveofDefeat]

7km high ship lol.