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Rethinking clipping...


Hotel26
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KSP is many things to many people.  It is rich with possibilities.  The only "right" way to play it is to have fun -- and if along the way you amuse/entertain/enlighten others, that's a decided bonus from KSP to everyone.

                                                                    

I recently built a plane with wing root tanks.  I like this technique because you can slide them fore/aft to balance the full/empty CoM.

I shift-gizmo'ed them nearly flush with the fuselage so that you could conveniently click them to refuel as long as you knew they were there.  My quip at the time was, "that explains why national surveys show Kerbals prefer the aisle seats".  I was modeling an actual airplane which has bulges at the wing roots indicating fuel storage there.

This is "clipping for aesthetics".

I've built another plane where I felt the best shape for the wings was the FAT-55, but it didn't provide me enough wing area.  Imagine placing two sets of wings on that aircraft.  Problem solved.  Works under KSP aerodynamics.  Looks awful.

So I slid them together to create the same shape wing but actually even more resembling that of a real-life wide-body.  Beautiful and it works.

The objections based on the dogma surrounding clipping would be that a) I am overlapping fuel (moah fuel) and b) getting twice the lift from "the wing".  No.  It's the same plane as the ugly one; I simply moved the pieces together for aesthetics.

There is a "clipping for performance".  (We've all done this.  Publicly or secretly.)  An example would be jamming 3 Junos into a service bay on a VTOL to get sufficient TWR to hover, when a) the service bay doesn't have room, but b) there's no decent way to solve it by separating the engines out and spraying them all over the assembly.  By "decent", I mean that avoiding this clipping would make the delicate VTOL balancing act ferociously harder.  (I did this in my Tern-R retractable-gear variant on Brikoleur's original Tern.)

I am very wary of this latter type of clipping because it's a slippery slope since performance gets to be very competitive.  This is why challenges generally exercise tight control over clipping, fairly enough.  I don't disdain the practice but it's crucial to clearly discern the different objectives for clipping.

Then there is the Replicant crowd.  :)  The objective is correspondence to actual aircraft/rockets.  Clipping is an imperative to reach the objective.  This makes sense.  This is a different arena within KSP.  I admire the replica.  I've gone as far as allowing myself to be inspired by actual machinery and imitate it in an impressionistic way.  I've learned to not give real names to mere impressions.  (Because the Replicants are armed and dangerous, thanks to BD Armory.  :))  But it makes sense and no one complains about clipping there; though lower overall part count is valued.

Finally, it's worth mentioning that there are some very creative, non-obvious and elegant ways to clip.  E.g. doing it without added excess drag.  And for mechanisms that are otherwise impossible or irksome; e.g. releasing a payload from a fairing for an air-drop.

                                                                    

Even more crucially, it is good to clearly discern the different reasons and objectives we "engineers" have for exercising our craft [skill, trade, art] in KSP, isn't it?

Edited by Hotel26
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On the subject of the Art of Clipping..

I was recently shown an elegant technique for clipping 3x (inline) Mk0 fuel tanks inside a small plane.  But how do you refuel them?

I will mention the ShipManifest mod, which I use to overcome the buggy KSP Crew Transfer feature.  It could also be used to transfer fuel to internal tanks.

Here's a mod-less technique that I think works.

  1. check the LF box in the Resources tab (with which I fly open at all times)
  2. Pin the internal tanks open
  3. Uncheck the LF box in the Resources tab.  Pinned tanks stay open
  4. click-select the source tank for fuel replenishment.  Pinned tanks disappear!!
  5. Briefly hover over the LF box in the Resources tab and the "pinned" tanks now re-open.
  6. Proceed with pumping fuel

Don't know how well-known this is, but it's not very obvious and it could be very useful to those who need it.

 

Edited by Hotel26
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Clipping for me is a creative way to ''create'' parts from other parts, custom build in more creative ways.

BUT, when it comes to perfomance clipping i am strongly against, if i clip two fuel tanks i make sure i ''punish'' that by reducing the fuel they can hold or just remove it entirely,

i am not even touching the clipping engines etc, thats a total no go for me.

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I'm on similar lines. I clip happily if the unused interior volume of the craft more or less matches the clipping, for example I have no qualms whatsoever about filling a nose cone or other structural part with fuel tanks or other gizmos; I even don't consider it cheating if I assemble them in such a way that the aero model thinks they're inside the other part, if that gives the craft an aerodynamic profile that's identical to one without the interior parts. Like here, for example -- all of that machinery is "inside" the Mk1 utility bay...

oQ372sS.png

... which I would consider cheating if I didn't then clip on the aerodynamic skin:

HTbelQg.png

The way I see it, I'm just using otherwise unused interior volume, and working around a limitation fo stock aerodynamics: with FAR, for example, the aero profile would be the same regardless of how I assembled it. 

The only situation where I clip for performance without feeling bad about it is when creating ballast elements for subs. Parts are ridiculously buoyant, so I don't have a problem working around that by clipping several ore tanks inside one another to make extra-dense elements. 

Sculpting things for aesthetics is perfectly fine in my book of course. And obv it's not even possible to make lots of things entirely without clipping, sticking wings or canards onto curved surfaces f.ex. will inevitably result in some clipping, never even mind placing landing gear and such. 

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10 minutes ago, Brikoleur said:

The only situation where I clip for performance without feeling bad about it is when creating ballast elements for subs. Parts are ridiculously buoyant, so I don't have a problem working around that by clipping several ore tanks inside one another to make extra-dense elements. 

My thinking, too.  Thanks for your examples.

My approach here is craft-file-editing to boost the ore capacity.  Then I use ShipManifest to "flood" or "blow" those tanks with sea-water.  (Until now, I have referred to this as the Tardis Effect...)

Maybe this is a third category, clipping for possibility.  Because I don't think reasonable submersibles can be made, especially not without buoyancy control, which opens up a whole new genre of "flight".

[If this thread turns into a comparison/exposition of clipping techniques, I would be very glad!  It's a very rich area within the KSP domain.]

Edited by Hotel26
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14 minutes ago, Brikoleur said:

Like here, for example -- all of that machinery is "inside" the Mk1 utility bay...

Just as an fyi, that isn't how aero clipping works.  It doesn't matter where you originally placed the part, only weather or not the CoM of the part is physically in the bay and the bay is larger than the part it is shielding (ie you can't shield a nerv with a standard 1.25m bay).  Same goes for fairings, where you originally placed the part is irrelevant, all that matters is that the CoM be within the fairing (and the aforementioned size restraints).

Edited by Lt_Duckweed
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I usually avoid excessive clipping because I think it tends to be more trouble than its worth, and as mentioned a lot of challenges heavily restrict clipping. I'll note here that the challenges I run allow clipping, but that won't necessarily help you - they're mostly about mission design, engineering, and navigation.

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27 minutes ago, Lt_Duckweed said:

Just as an fyi, that isn't how aero clipping works.  It doesn't matter where you originally placed the part, only weather or not the CoM of the part is physically in the bay and the bay is larger than the part it is shielding (ie you can't shield a nerv with a standard 1.25m bay).  Same goes for fairings, where you originally placed the part is irrelevant, all that matters is that the CoM be within the fairing (and the aforementioned size restraints).

Is that so? I'll have to re-verify my experiments then. 

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I have two separate saves, one for creating replicas and my own designs, one for career and rocketry. İn my plane save i don't mind clipping but i still care about not putting two engine on same place or squishing fuel tanks in tiny space, in my career save i strictly stay away from clipping cuz i kinda find it bit cheaty. I wouldn't judge anyone who does it tho.

My main reason to use clipping is purely visual.

unknown.png

 

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My views on clipping are simple: I don't restrict myself in sandbox or career of any form of clipping (except the misleadingly named 'part clipping' option in the debug/cheat menu - I do try to avoid that, but only because it can lead to difficult to correct/diagnose issues with craft).

First of all: building craft in KSP is already limited enough in many unnatural ways, leaving us lacking very basic and common engineering techniques. Apparently, despite clear visual evidence from the existing part set and the KSC buildings that kerbals have the capability and tools for molding and bending metal, riveting and soldering parts together, building intricate multi-functional parts, and fitting and integrating all kinds of resource containers into various kinds of volumes... none of those tools or techniques are available to us in the KSC. At least not in any apparent way.

So how is it then that kerbals manage to mold and fit a complex pressurized cabin, monoprop tanks, RCS engines, sensors, antennae, wiring and computer equipment into a small conical shell? It took me some time to figure this one out, but once it dawned on me, it was stunningly obvious: the Pauli exclusion principle does not apply in kerbal physics.

Kerbals do not need tools to integrate components into a single part... because matter can occupy the same space. I know, crazy right? But it's true! Try it!

So why would a society limit themselves to rules that do not apply in their universe? Who in their right mind would stunt their creativity and engineering options by doing such a thing?

I've never looked back after that epiphany. So these days, I do as follows:

  • For forum challenges or requests, I abide by the specified challenge rules or the limitations imposed by the requester.
  • For craft I share on KerbalX, I try to minimize clipping to the degree I feel may appeal to the widest audience, but I will still clip when I feel the design or performance goals call for it.
  • For my own craft, even in career, there is no limitation at all. If factory default KSP physics allows it, I use it. Applied Engineering.

Seriously though:

We can't build custom-designed parts. We can't mold the aerodynamic shell. There's no built-in way to put the often underutilized volume of parts to good use. And we are severely punished by counter-intuitive physics that on one hand makes parts entirely unshielded to airflow regardless of placement, and on the other hand arbitrarily kills their functionality while inside enclosed spaces (even though they still work while phased inside 'solid' parts!). A ton of disadvantages, very few benefits. I think we're allowed a LOT of leeway in employing the few benefits we do get over regular physics to compensate.

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Since I'm big into realism, (play with TACLS, Persistent Rotation, Connected Living Space, Mandatory RCS, etc.) I only clip where the part has an obvious and visible emptiness that can be filled with something useful. For example, the space inside most decouplers is wasted empty space, so this is where I usually stick RCS tanks, remote guidance control units, antennas, batteries, etc. that I use on lower stages for recovery. (I try to fully recover all my launch vehicles... waste not, want not, I always say!)

As for people that clip into other parts? Meh. I don't tell other people they're having BAD-WRONG-FUN by doing it and being all 'judgy' about it. I mean, how can you "cheat" at a single-player game that has no set goal? (Ok, using the "infinite fuel" mode is really kind of "cheating", but that's how my youngest son learned how to play KSP, so I know it has a use, so... ::shrug:: )

Edited by RobertaME
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On 8/21/2020 at 11:12 AM, Brikoleur said:

Like here, for example -- all of that machinery is "inside" the Mk1 utility bay...

On 8/21/2020 at 11:52 AM, Brikoleur said:

Is that so? I'll have to re-verify my experiments then. 

I didn't think it worked that way either, and if the storage bays work like fairings, then the props that I make that are covered in fairings wouldn't work, like so:

Spoiler

A2yRgEZ.png

CJGnUEH.png

Also, if you use the backwards nose cone for LF, then you would be duplicatng volume, but....

 

On 8/21/2020 at 7:20 AM, Hotel26 said:

I've built another plane where I felt the best shape for the wings was the FAT-55, but it didn't provide me enough wing area.  Imagine placing two sets of wings on that aircraft.  Problem solved.  Works under KSP aerodynamics.  Looks awful.

So I slid them together to create the same shape wing but actually even more resembling that of a real-life wide-body.  Beautiful and it works.

The objections based on the dogma surrounding clipping would be that a) I am overlapping fuel (moah fuel) and b) getting twice the lift from "the wing".  No.  It's the same plane as the ugly one; I simply moved the pieces together for aesthetics.

Do you mean something like this?

isYnn7B.png

This is about the limit for me. As for duplicating volume, I could just offset them vertically. In other instances when wings are clipped, it gets you unreasonably short wingspans, which do matter when it comes to not knocking naything during landing, fitting in fairings, etc. However, that can almost always be avoided by vertical offset, with your wings ending up looking like a very thick box... so yes, I accept clipping for aesthetics, but not performance.

On 8/21/2020 at 7:20 AM, Hotel26 said:

There is a "clipping for performance".  (We've all done this.  Publicly or secretly.)  An example would be jamming 3 Junos into a service bay on a VTOL to get sufficient TWR to hover,

I think I better example is just clipping everything into one tiny fairing/service bay, so your craft has ridiculously low drag. Other examples are stacking engines end to end, then clipping them so they don't obstruct each other's thrust, and thus giving you a ridiculously high thrust:cross section ratio (one of the things that makes the vector so good).

Clipping all the tanks into on small area also makes it trivial to avoid shifting CoMs... etc

But I agree with you, clipping for aesthetics is fine.

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I will submit this [not my own work] for consideration:

https://imgur.com/a/iUkIgWq

I think likely two things may be observed readily:

  1. it is heavily clipped
  2. the level of thought, judgement and skill exhibited herein is strikingly impressive

This is a genre of creativity that is difficult to ignore, isn't it?

Edited by Hotel26
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59 minutes ago, Hotel26 said:

I think likely two things may be observed readily:

  1. it's a tour de force of clipping
  2. the level of thought, judgement and skill exhibited herein is strikingly impressive

Personally, I would describe it as:

  1. Dictated by the (largely self-imposed) functional and aesthetic requirements - in this particular case, the wish for it to fit 'seamlessly' (visually if not physics-ly) in an Mk2 fuselage without incurring too much drag
  2. Inevitable (VTOL functionality is a common wish) and unavoidable (due to a distinct lack of stock non-clipped solutions, ie. any Mk2 parts offering drag-friendly high thrust in ventral/dorsal directions)

It's basically pairing the non-exclusion principle with the equally Kerbal Moar philosophy: when all else fails, add moar (into the same space).

In a different universe, we would design and custom-build an engine assembly that through the use of sliding doors, well-placed vent slats, piping, structure and skin would fit all the necessary pieces of machinery into the required Mk2 cross-section without any violations of traditional physics. Likely, it would need more volume than a single Mk2 'unit', in which case we would simply lengthen the section to add to the available volume.

None of these options are available to us in KSP; but we can make parts occupy the same space. So we clip.

Edited by swjr-swis
forum ate half a phrase
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1 hour ago, swjr-swis said:

It's basically pairing the non-exclusion principle with the equally Kerbal Moar philosophy: when all else fails, add moar (into the same space).

In a different universe, we would design and custom-build an engine assembly...

None of these options are available to us in KSP; but we can make parts occupy the same space. So we clip.

I prefer mods over high degrees of clipping. Keeps the part count down and less likely to attract the Kraken.

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I use clipping often because I like my vehicles to look realistic. For me, unless the situation is dire, form > function. IRL, things aren't made of a small selection of parts, they are custom designed for their purpose. Clipping can help offset the limitations of a parts inventory, while keeping its benefits.

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5 hours ago, sturmhauke said:

I prefer mods over high degrees of clipping. Keeps the part count down and less likely to attract the Kraken.

I used to be a mod user like you; then I took NRE in the knee.

There's some great mods out there, but they sometimes add their own flavour of krakens, and clipping solves some inherent issues that mods just don't.

An obvious example: no amount of new part mods solve KSP's severe punishment of open stack attach nodes with drag. Attach a nose cone, clip into the engine to where exhaust is no longer occluded - drag almost entirely removed!

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I clip parts with almost every build but thats just tied to what i like to build.

A significant chunk of stuff i do in the game is building replicas or just general visual builds. Apart from that i like to build things with stock mechanics or trying to push various aspects of the game to its limits. While i do agree that clipping too much can get dumb if its built for the sake of performance, at a certain point it actually becomes impressive dealing with the 100s of  fuel tanks and parts all existing in the same place.

Many KSP parts just have dumb dead space (like the 2m SAS wheel) while others end up making really bulky rockets because of the predetermined shapes that ksp parts have, so in general the practical clipping has never been a problem in my opinion. Furthermore, clipping for performance has never really bothered me either because if you are significantly clipping it would be for a goal of pushing KSP past what you would normally be able to do. At this point when KSP is pushed that far it is no longer about optimizing your rocket, its more about gaming around KSP's systems (cough aero cough). Even without clipping it would be like that, while clipping simply opens more windows into what is possible. 

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On 9/2/2020 at 4:42 PM, swjr-swis said:

Attach a nose cone, clip into the engine to where exhaust is no longer occluded - drag almost entirely removed!

This right here x100.  I did the math and at sea level at mach .9 (which is where backface drag peaks before starting to drop off again) you are losing something like 7% of a rapier's thrust to it's own backface drag.

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On 9/2/2020 at 10:42 PM, swjr-swis said:

An obvious example: no amount of new part mods solve KSP's severe punishment of open stack attach nodes with drag. Attach a nose cone, clip into the engine to where exhaust is no longer occluded - drag almost entirely removed!

Wasn't this shown to no longer be a factor since version 1.0.0 or something? I'm sure there was a big thread about it in response to Stratzenblitz75's '3 parts to X' videos, but I can't find it.

Edited by Rocket Witch
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6 hours ago, Rocket Witch said:

Wasn't this shown to no longer be a factor since version 1.0.0 or something?

It is absolutely still a factor. Don't take anyone's word for it, regardless of their online following; just try it - takes all of 2 minutes and one revert to prove it to yourself.

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