Is part-clipping bad?

[MisterKerman]

I've always wondered if there were risks associated with clipping parts into eachother. I've never had parts explode on me often enough to determine if clipping was the issue, but generally avoid it when designing craft.

The thing is I can't stand having objects floating in place not attached to the craft so I often inset them into the craft the way I feel looks most natural, and it's generally fine. But...

I don't look at the debug menu or fiddle around with code etc; I have my hands full simply playing the game. I'd like to hear from experienced members what their views in regards to part clipping are, and why/how they do it 

[4x4cheesecake]

Usually, part clipping is no problem at all. A craft cannot collide with itself so clip as much as you want

Just be careful with parts which will decouple/undocked at some point, for example a booster. If the booster is clipped into the main rocket, it will explode or at least create some unexpected forces on your rocket

[MisterKerman]

That's super good advice. I'd never considered that to be honest but I try not to make clipping a habit outside of cosmetic purposes and always as little as I can manage for the effect. (No fuel tanks inside of fuel tanks or any other sketchy nonsense.) I've definitely had fixed parts explode and I suspected clipping to be the issue, but it sounds like it must have been some other sort of bug.

Parts within the same craft really can't collide? What about the stock landing gear contraptions (such as cargo bays that would torque themselves open with landing legs before cargo bays were were implemented.) or Kraken drives?

I always felt like my paranoia was warranted because of stuff like that.

Edited May 28, 2019 by MisterKerman

[4x4cheesecake]

30 minutes ago, MisterKerman said:

Parts within the same craft really can't collide?

I'm pretty sure about it

 

30 minutes ago, MisterKerman said:

What about the stock landing gear contraptions (such as cargo bays that would torque themselves open with landing legs before cargo bays were were implemented.)

Most of these contraptions uses some kind of "bearing" which is separated from the main craft. I definitely don't know all the possibilities, but the regular case is shown in my video above  

[Adenosine Triphospate]

1 hour ago, 4x4cheesecake said:

 

 

haha that video's so cursed!! It makes sense now, all the times my rover/docked spacecraft kept wobbling and destroying itself it must be because of autostrut, not what I had assumed to be unconventional clipping.

[Foxster]

The downsides for me are:

1. It can feel too cheaty. Full tanks inside full tanks and such are just not realistic. Doesn't bother some folks. 

2. If the craft is going to split at some point then clipped parts can get stuck together messily. 

3. Engines inside or very near other parts may be occluded and not produce thrust. 

[Flavio hc16]

if i'm not wrong ( it might be an outdated information) the stock aerodynamic model doesn't care of your clipping, it will see still the part as it is when is outside of the other part clipped

[Foxster]

Just now, Flavio hc16 said:

if i'm not wrong ( it might be an outdated information) the stock aerodynamic model doesn't care of your clipping, it will see still the part as it is when is outside of the other part clipped

Yup. Drag and such is calculated based on initial placement - as long as only translated and not rotated. There is no such thing as drag occlusion except for in-line attached parts in KSP. 

[Zhetaan]

I generally avoid clipping because of the separation-followed-by-exploding-parts issue, but I'll do it in specific situations where it makes sense.  For example, stock ladders require clipping to work at all; look at the part (try mounting a ladder on a girder to see how much of the ladder is a storage case that clips into the vessel).  Because of the way it mounts, I assume that it is purely visual and that there is no collider, but even if there is not, ladders visually clip.

For a more practical example, I'll put a Place-Anywhere RCS thruster into the middle of a four-way block to make a five-way thruster if I need (or want) one, because that makes sense.  I clip wing parts together to get better-looking wings, but I hesitate to clip wings to get double lift from what appears to be one wing.

Before service bays, I would clip parts into the insides of structural fuselages because structural fuselages are hollow.  They absolutely can work as service bays.  Before I used modded fuel-bearing adapters, I would occasionally clip small fuel tanks into the Rockomax 2.5-to-1.25 adapter, though the amount of fuel I gained that way was usually not worth the trouble.  Stock aerodynamics didn't reward that kind of nonsense at all, either, but in fairness, that's what FAR was for.

[Claw]

On 5/28/2019 at 11:38 AM, MisterKerman said:

Parts within the same craft really can't collide?

In general, this is correct. The parts within a single vessel themselves can't collide.

 

On 5/28/2019 at 11:38 AM, MisterKerman said:

What about the stock landing gear contraptions (such as cargo bays that would torque themselves open with landing legs before cargo bays were were implemented.) or Kraken drives?

There are two methods at play with this one. The earlier version of wheels used a different system entirely, which essentially boils down to the existence of wheel colliders which were not ignored by the rest of the vessel. Shoving this collider into another part would cause joints to bend (because they are bendy), resulting in the ability to build things like moving cargo bays and kraken drives. This is no longer how the wheels work. The new wheels use ray casting, so it technically not a collider. The ray casting is not ignored internally to the vessel.

 

As others have pointed out, part clipping really only becomes a major catastrophe when you cause an event which creates two vessels (such as staging or undocking). The "ignored" collisions become active between the parts of one ship vs. the other (but still ignored internally for each). So if two parts are clipped, but suddenly belong to a separate vessel after staging, they will immediately collide.

 

[MisterKerman]

Ah okay, well thanks for the information you guys. It looks like there were a few members other than myself that got a little bit of clarity out of this too so I'll probably leave this topic to wither and die rather than closing it in case someone else has anything to add. I'll continue to part clip as conservatively as possible, but it's good knowing that I was worrying a little too much about it for what that stress was worth.

[Incarnation of Chaos]

The worst thing that can happen is a clipped tank shimmies loose and then becomes a projectile at orbital velocity that wrecks the rest of your stack; however, this is a structural problem and could happen with non clipped tanks. Autostrut also invites the kracken and autostrutting clipped parts can really lead to fun things when doing large timewarps; but again these are all stock issues. So in my opinion if your craft is failing because of clipped parts; generally it would have failed otherwise and you need to look at the overall design. 

So part clipping won't cause failures you would otherwise not have; this means on a purely mechanical level that part-clipping is not "Bad" or "Good". It's just another tool in the toolbox; i tend not to use large amounts of clipped parts or only partially clip them mainly due to Z-fighting making the spacecraft go partymode. But i personally don't mind it when i need to squeeze out every bit of performance from a lander/second stage; or i'm using large-volume propellents like LH2 that would otherwise occupy much more space.
 

So i basically have my own internal "Ruleset" when it comes to clipping; you will find plenty of others that are similar or just don't do it at all. And that's the awesome thing about KSP; you can do whatever seems most realistic/immersive/useful for you and rock on.