• Who needs a level runway anyway?


    JPLRepo

    Do these look familiar:

    PoFhk8C.jpgarh5M8l.jpg

     

    Runways are indeed not flat. And KSP’s runways are no different.

    In fact one might argue that KSP’s runways are too flat! But that’s not what you the fans (or the planes in KSP) wanted. So I was given the task of looking into the Runways.

     

    Well hey I thought.. Can’t be that bad. They don’t look like this do they? Or maybe they do…

     

    gfRmYzT.jpgTQAFxHK.png

     

    Let's Begin!

    First impressions were this should be a simple job. Just align the models in Unity. Why hasn’t anyone done this? Well, I can tell you, it’s not that easy at all. The issue begins when you look at the size of the runway models and small inconsistencies that seem to creep in when you import the models into the Unity engine.


    Unity has some tools that support object positioning. But the best tool for the job is the vertex snapping tool and this works best when your mesh (the actual triangles that make up the model) has a physics collider attached to it and these have straight, square edges. This is where the fun begins because the Runways in KSP are made up of separate sections which do not have square edges or lend themselves very well to having physics colliders added to them easily because of their shape.The ends and bases of them are rounded and extend into the ground and Unity changed the way physics colliders act from when these models were first created for KSP and the current versions of Unity KSP is running under now.

     

    Level 3 Runway

    Recreating the models was just not an option given the time that would take. So the process I came up with was to take the existing model, create cut down duplicates of the model meshes that were square so they could be used as colliders (but also had edges that matched the existing seams), line it all up in the modelling software and export.

     

    Next we import to Unity. Using the new meshes I began adding unity physics colliders and then vertex snapping the sections together. Once this was done the Unity objects were put together into a new Runway prefab (a term in unity which creates a prefabricated object which can then be instantiated when the game is running).

     

    Finally all the references to the new prefab must be re-generated to hook up all the code that supports destructible and upgradable facilities.

     

    What could go wrong? Well there are a lot of these references scattered throughout the game setup. You can easily miss one or two and then wonder, “Where'd my shiny runway I spent so many hours recreating go?”

    KpHIiJY.png

    Once the runway was in the right position there were still some small gaps, and while not letting my OCD get in the way too much, I began painstakingly doing fine tuning adjustments to the positioning of the runway sections.

     

    A bit later and finally everything is right and you get the new and improved runway ready for testing.

     

    KOOPZMe.png

     

    Rinse and Repeat

    … And so the process then gets repeated with the Level 2 runway.

    nnWfb9j.png

     

    Luckily I've now got a workflow happening and the Level 2 runway is done in half the time.

    With that done… Now what should we do with that lumpy bumpy Level 1 runway?

     

    But that's a story for another day.

    Edited by JPLRepo

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    Numbers:

    R - tail wheel reacion force

    a - distance between Com and front wheels

    l - distance between wheels

    R - radius of the descending path

    Fd - downforce

    m - mass

    g - gravitional constant

    F - total force put to the CoM

    v - tangent speed

    F = (m*g) + (m/R * v^2) + Fd // gravity + centrifugal force + downforce

    R = F * a / l                  // from static equations at the touchdown converted from the zero sum of torque at front wheels (civil engineering course year 1)

    even without the centrifugal force and downforce the rear wheel reaction is only smaller than the "50% of mass" if the CoM is closer to the front wheels

    aww, forgot to post u some pictures/movies if u dont believe maths, all of those planes landing with the nose up and touching rear wheels first, using the last drip of UPforce to decrease wheel impact and reduce speed at the touchdown :*

     

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    4 hours ago, Rybikson said:

    [...] the nose up and touching rear wheels first, using the last drip of UPforce[...]

    I wonder if you don't want to understand or if you simply can't.

    Of course they land with the nose up. As I said the lift is not only determinated by wing shape and size, but also by wind speed and angle of attack.

    Increasing the angle of attack (without stalling) means more lift with same speed. Or same lift by less speed. It also increases drag and help reducing speed.

    But if your front wheel is further down ... that means your nose is up when all wheels are touching, means you have a higher angle of attack from the get go, means if you land that way your speed is also almost enough to lift you off the runway, but that is not want you want.

    Once the back wheels are touching you want to decrease the angle of attack (aka bring the nose to level) to reduce lift drastically the increased weight now presses the wheels down enough that you are able to use breaks ... which you can't if you have a low front wheel. To get then the same effect you need to push your nose "down" after all wheels made contact.

    It might be that you get away with this kind of construct in KSP, but you won't in RL.

    Also you can see in your video that they all come down nose first, then close to the runway they pull the nose up reducing vertical speed almost to zero, and also reducing horizontal speed in process, then (after contact) lowering the nose to get full grip of the gear.

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    On 2/20/2017 at 5:53 AM, TheEpicSquared said:

    That would be awesome!

    There's no official runway, but you can emulate this just by landing on one of the mountain sides. I've done it via both vertical and horizontal vessels, it is NOT easy.

    Also, I had no problems landing before or after the edits. Don't see what the problem is. Then again, I could land on just about anything. I landed on a near vertical cliff once, I really should have took a photo of that. Only way I kept from sliding away was by keeping breaks on and then retracting the landing gear.

    Edited by Maelstrom Vortex

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    Re: Level 1 runway

    Could you please make it just like Level 2 runway, but 2x shorter?

    Because bumpy Level 1 runway is worse than grass, and grass is just 1 meter away, so nobody uses it - everyone uses grass. So why does current level 1 runway even exist in its current form...

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    A flat runway, even if it's short and irregular on the edges, is a must-have. Else the grass is a better proposition.

    I would be pretty okay with it being wobbly (ie, the edges are not straight) though - but I'd still really prefer a setup where all the runways are properly straight and level (sans bumps); what you're paying for is /capability/, after all, and having the L2 and L3 runways significantly wider and longer would be perfectly sufficient.

    Especially if the L3 runway had a proper suite of landing lights. :)

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    Could you please make the level 3 runway 4x longer for heavy planes?

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    2 hours ago, Kerbal101 said:

    Re: Level 1 runway

    Could you please make it just like Level 2 runway, but 2x shorter?

    Because bumpy Level 1 runway is worse than grass, and grass is just 1 meter away, so nobody uses it - everyone uses grass. So why does current level 1 runway even exist in its current form...

    I object, I use the level 1 runway, very carefully.

    Lengthening the level 3 would be nice. Sometimes drogue chutes and regular chutes, even reverse firing engines just aren't enough. (Especially when you have an airliner for a space plane.)

    6YDYU6R.png

    And yes, it still works on the current aerodynamics config.

    Edited by Maelstrom Vortex
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    lol the visibility from the pilot's seat must be... not so good ! :D

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    21 hours ago, Maelstrom Vortex said:

    I object, I use the level 1 runway, very carefully.

    Lengthening the level 3 would be nice. Sometimes drogue chutes and regular chutes, even reverse firing engines just aren't enough. (Especially when you have an airliner for a space plane.)

    6YDYU6R.png

    And yes, it still works on the current aerodynamics config.

    I object ur objection and second object ur request for a longer runway lol.   Thats what SRB's are for.    And if ur using that big of a plane.... Use the grass lol

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    On 27.02.2017. at 9:54 PM, Bizz Keryear said:

    But if your front wheel is further down ... that means your nose is up when all wheels are touching, ...

    Typo somewhere ? Or I didn't understand something properly, tried to read this several times but this sentence have no sense to me. What do you mean by further down ? Shorter front wheel leg ? If front wheel leg is shorter compared to rear landing wheel leg and both are attached to same (center) line of fuselage, shouldn't nose go down ?

    Either way, it is pointless to discuss how landing gears must be placed on plane. Each aproach have pros/cons depending how someone is skilled with each design and how you are able to counterpart downsides of each design.

    Personaly, I have most luck with nose tilted down somwhere between 1-5 degree, but this is my personal preference, not everyone found that is good choice, have to find way to counterpart additional downforce on wheels from negative angle of attack. Similar to most famous craft closely related to KSP:

    Space_Shuttle_Discovery_slows_to_a_stop_

    Picture is not entierly taken from side, but even with eyeball it is noticable that nose is slightly tilted down while all wheels touching ground. Front leg is noticable shorter than rear legs. Again, not each aircraft must be design in same way, it is pointless to discuss that something must be created in exact same way like somebody else designed his craft.

    Sorry, that was slightly offtopic, discussion was about runways. I agree with proposed increased length of lvl3 runway. 1.5 x of current length of level 3 runway would allow takeoffs with TWR less than 0.3 and more reasonable wingspan and wing area. Or create level 4 runway with increased length, but making it more expencive to upgrade.It is much more needed for those folks who want to replicate skylon a like crafts. Without consideration taking off from grassland.

    Level 2 runway is good as it is, not too perfect, but not too bad either.

    Level 1 runway - it is good to have some "bad" runway type in game, it would lead to some creative designs to overcome isues with bumpings. My only complain with such runway is supported plane weight and size. It more / less forcing players to upgrade runway to level 2 much before creating more complex crafts.

    It would be good if at list friction on level 1 runway is better than on grass, making it more desirable to land than grass. Not only grass, but all of other terrains on Kerbin should be more difficult than level 1 runway. Lvl one runway should be used as testing ground for crafts, to see if you are designed craft well enough to b e able to land safely on even more rough terrain.

    It might not be bad idea to get some additional runway nearby, similar to level one runway, but with much more length as addition to existing level 1-3 runways in game.
    But at the same time something have to be done with other terrains, to be less desireable than runway. Random friction on other terrains is first thing to pop on my mind to achieve this, somehow.

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    I think of Level 1 runway as the training runway that teaches you to land everywhere else on Kerbin.

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    Quote

    With that done… Now what should we do with that lumpy bumpy Level 1 runway?

     

    As others have noted, the main complaint with the Level 1 runway is that it's surrounded by completely flat ground. It feels unfair and pointless. The best way to improve it would be to leave it as it is, but make the ground surrounding  it lumpy or otherwise harsh for landings. As an alternative, modify the off-runway area's surface friction to make it difficult to land on. As a hacky example, a PartModule attached to the wheels that detects when they have ground contact with anything other than the runway, and applies a random noise function to wheel parameters such as frictionMultiplier. Get creative and I'm sure you can come up with something quick, simple and fun. :)

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    On ‎2‎/‎26‎/‎2017 at 4:41 PM, Rybikson said:

    if u need any special craft desing ill help / if u want to argue without scientifical background or experience just leave me alone ;P

     

    I'm a licensed Commercial Pilot. I know what I'm doing.

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    2 hours ago, pizzaoverhead said:

     

    As others have noted, the main complaint with the Level 1 runway is that it's surrounded by completely flat ground. It feels unfair and pointless. The best way to improve it would be to leave it as it is, but make the ground surrounding  it lumpy or otherwise harsh for landings. As an alternative, modify the off-runway area's surface friction to make it difficult to land on. As a hacky example, a PartModule attached to the wheels that detects when they have ground contact with anything other than the runway, and applies a random noise function to wheel parameters such as frictionMultiplier. Get creative and I'm sure you can come up with something quick, simple and fun. :)

     

    Everyone will then land several kilometers from KSC and recover from there, because recovery cost away would be less than crashed plane due to high risk on bumpy runway or grass.

    One will have to modify ALL grass on kerbin, which would also require to modify mountains too, which in turn will make regular exploring very very hard.

     

    Why not make L1 runway 2x shorter version of L2 runway, and L3 runway 2x longer than current?..

     

    PS. Your SoundManager plugin rocked before 1.2.2 rolled out :wink: Thank you a lot for the mod!!

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    5 hours ago, Kerbal101 said:

     

    Everyone will then land several kilometers from KSC and recover from there, because recovery cost away would be less than crashed plane due to high risk on bumpy runway or grass.

    One will have to modify ALL grass on kerbin, which would also require to modify mountains too, which in turn will make regular exploring very very hard.

     

    Why not make L1 runway 2x shorter version of L2 runway, and L3 runway 2x longer than current?..

     

    PS. Your SoundManager plugin rocked before 1.2.2 rolled out :wink: Thank you a lot for the mod!!

     

    If you use a modifier method like that mentioned above, it's cheap to affect anything that isn't the runway, covering the whole planet without any extra effort. For rovers, the roughness is only an issue for the high speeds that spaceplanes normally endure after re-entry, greater than 100 m/s. Normal roving speeds are much lower, so you could have the effects of a rough surface fade out at speeds well before they would be affected.

     

    Soundtrack Editor is back up and running for 1.2.2 :)

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    Ruedii

    Posted (edited)

    I say the level 1 runway should be not as good as the other two, but still OK.  It should be shorter and narrower as well, and it's overrun area and side areas should be bumpy.

    The lv 2 and 3 runways should have reduced rolling friction on the wheels compared to the Lv 1 runway and grass.   If you can add materials logic for it, the pavement areas of KSC and the runway should have very low rolling friction, while the dirt and well groomed grass should have moderate rolling friction.  The non-groomed grass everywhere on kerbin should have high rolling friction.  If this logic isn't already sitting there from Unity unused, don't bother, it's not worth the time at this point.   You can always add it later.

    The same should go with the level 2 runway if you can further modify it.

     

     

    Edited by Ruedii
    Moar suggestions

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    Why is the entire KCS not bonded to a larger target object. This would avoid some problems with scaling planets and jagged separation lines. (answer is, probably, 'cause unity)

    Why is a runway elevated from the ground around it, unlike virtually every runway not in the third world or having some special circumstance (ie in a marsh 'cause NIMBY). I mean I watched shuttle landings at Edwards, and if they messed up landing by coming in early big woop just more dry lake, replace/rebuild the landing gear just like they did anyway.  Can't tell you how many craft I've carefully driven off the berm and take off from the KSC flat area grass.

    Yes I know KSC(Cape Canaveral) is elevated in a marsh, has water around it and all together is a disaster if you aren't on it.  I've heard landing managers complain about it too.  Only reason I think its worth having is as a single orbit abort landing strip.  Plenty of big military landing fields that don't need ponds to keep wild hogs off the tarmac.  (just visualized a herd of wild Kerbeast wandering on to the runway as a Mk3 Shuttle lumbers in...)

    https://en.wikipedia.org/wiki/Shuttle_Landing_Facility#/media/File:Shuttle_Landing_Facility.jpg

    Richard Merritt/Landing Support Manager: podcast talking about the runway and why it took so long to start using it. (spoiler 'cause Edwards isn't elevated in a marsh/woods and alligators) https://www.nasa.gov/multimedia/podcasting/landingsites.html

    Grognard childhood memory time:  Location: Edwards.  The sonic booms from the shuttle are amazing.  Sitting in the car waiting for it to come down it sounded like someone slammed a baseball bat into the hood of the car a couple times.  This speck appeared a long while later and fell like a brick. Then it fell slightly less like a brick and landed. My family was moving cross country that day and I watched from the top of our rented u-haul truck. Crowd was huge. We didn't even know it was happening that day and as we drove up decided to add to the crowd. I don't think we could see it making descent curves.  Think it was STS-1 but i might be mistaken.

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    Ruedii

    Posted (edited)

    19 hours ago, Bornholio said:

    Why is the entire KCS not bonded to a larger target object. This would avoid some problems with scaling planets and jagged separation lines. (answer is, probably, 'cause unity)

    Bonding KSC to itself would work well as well.  However a virtual "foundation object" under KSC would work even better.   This is similar to using a mounting block to improve precision in engineering.  It is a simple way to reduces rounding errors and makes everything snap together nicely.

    The way I would actually mount them is each section (e.g. Runway, SPH, VAB, Lauchpad, etc) get it's "foundation model" mounted to the main foundation plane.  Then other models are attached on top of that foundation model.

    The foundation models used for each section, which handle the leveled ground, should have very slight slopes at the end to reduce problems with any smaller seams that still do occur.

    Every ground or foundation mounted object should have a base of some sort that runs below the ground to prevent visible seams.  They should be mounted quite a ways below the surface of the object they are tied to, much like real life construction.  This isn't a graphics performance concern like it was in the past.  Modern graphics drivers handle culling fully occluded objects nicely, often a lot better than game engines.

    Edited by Ruedii
    Spit 'n Polish
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    *Remembers time I landed my space plane on a terrain area "Runway" that was the most unlevel bumpety roller coaster course that I ever remember*:o Poor Jeb...

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    Maybe you should make the grass have certain effects as well; people are now using the grass next to the runway AS the runway instead of upgrading it. I don't think that's very realistic... when was the last time you saw a 747 land on the grass next to the runway because the runway was rougher?

     

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    Please leave the level 1 runway as it is. The bumpyness is a feature not a problem.

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    I guess that leveled level 1 runway should be better than forcing players to use grass. At least when there is still no penalty from taking off / landing on grass nearby.

    If SQUAD ever deceide to change behaviour of other terrain surfaces than it might have sence to have more bumpy runway, but with better friction than grass or something similar.

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    Urses

    Posted (edited)

    @kcs123

    Not realy a penalty.

    But if you go for max salvage in early Game (20% and lower on cash sience whatever) you will recover on runway.

    I go mostly for Startpad t1 if i try to do so. Because its lever with the Grassland around and for gamemechaniks it's no trade off where you recover Planes or spaceships Runway or Startpad.

    Funny Kabooms 

    Urses 

    Edited by Urses

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