Bridging the Dres Canyon | Stock KSP 1.10.1

between the orbits of duna and jewel there is a lonely dwarf planet called drace at first glance drace does not appear to be an exciting destination it's not a particularly large or small body it's smaller than the moon but still a bit larger than ike so its gravity doesn't pose any unique challenges its surface isn't really unique either it's got some craters scattered about and a mix of lowlands and highlands much like any of the other planets and to top it all off it's got an exciting color scheme of dark grey and light grey mean it's kind of a boring planet right or at least it would be if it weren't for one special feature that it has in the southern hemisphere near the equator there is a gargantuan canyon dashed into the dressian highlands at over 20 kilometers long five kilometers wide and over two kilometers deep this is not only the most striking feature of drace it's also the largest canyon in the entire game now this got me thinking is it possible to build a bridge across it it does seem crazy but let's roll with it and see what we can accomplish here now as i mentioned earlier the canyon is almost five kilometers across at its widest point that's actually longer than any single span bridge here on earth that said drace also has a much lower gravity than earth the gravitational acceleration at its surface is about 0.1 g's which greatly reduces the load our bridge has to support if you consider this fact it is certainly possible to build the dress bridge with real-life materials and indeed the strength of the parts in ksp is not the problem for this bridge the actual problem comes from how ksp handles terrain and vessel loading let me explain in the stock game crafts that are landed on a surface are unloaded when you move more than 2.5 kilometers away from the craft's root part that means if we place the bridge on one side of the canyon the bridge will simply not load when you're on the other side of the canyon can we get around this somehow what if we place the root part at the center of the bridge with this setup the root part would be within 2.5 kilometers of either side and it should load right well it would if we could even land it in the first place as it turns out the root part is too far away from the supports of the bridge and so the terrain colliders no longer load correctly which means our bridge just does whatever this is verdict it just doesn't work sadly ksp physics makes this a mess the amount of kraken involved in making a bridge this long is just too much to handle you'd be right in thinking that this is impossible and i was right there with you i didn't think these problems could be overcome either that is until i found something interesting you see ksp actually has two loading ranges one loading range is for loading the craft itself this is the 2.5 kilometer range that we discussed earlier however ksp doesn't actually load physics until we are within 200 meters of the root part before we reach this range the craft is perfectly rigid and does not fall under gravity you can see that in this demo here take a look this structure is impossibly cantilevered off the end of the vab until we get within 200 meters of it at which point physics loads in and topples it to the ground now one very important rule here is that the loading range is defined as the distance to the root part not the distance to the center of mass as a result we can offset the root part over 200 meters away from the structure itself so that we don't enter the physics range when we approach it now take a look we can approach this new structure and even drive on top of it while its physics aren't even loaded so the colliders still work but the physics are not loaded can we stack these segments the answer is yes we can indeed land these segments on top of each other and we can keep doing this to achieve any length we want just look at this we are now adding segments further than the 2.5 kilometers of the segment we started stacking them on and look it's not even loaded anymore and the rest of the segments are still there floating in the air this is the tech we will use to build our dress bridge of course we just have to be careful not to enter the physics loading range of the vessel or else yeah it'll just fall apart we now have the technology let's go build this thing the first thing we need to do is send a foundation to start stacking the segments on this is because the terrain is not level so we can't just stack the segments on the terrain directly and expect them to line up to address this i built this foundation craft here [Music] the transfer address is standard and boring so i'll quickly skip through this okay let's get on to the landing for the side of our bridge i picked out two points spanning the canyon that were similar in height and then placed marker probes on them despite my best efforts though i could not find two points at exactly the same height it turns out that one side of the canyon is significantly taller than the other so the bridge will have to have a slight incline to account for this the foundation has an orb of adapters at the bottom to pivot on and has a powerful array of rcs thrusters to keep it pointing towards the other marker to make sure the alignment was correct i created this crosshair out of flags and some small decouplers with that the alignment is completed and we can ditch the landing thrusters and rcs pods at which point i immediately pause the game and then go to the tracking station since the root part of the foundation is more than 200 meters away from the main craft the foundation is now locked in place you can see that and how i can drive the scout rover on top of it without the foundation moving at all the next step is to send the bridge segments themselves of course we're gonna need more than one segment to span this gap since each segment is about 500 meters long and the markers are 5.5 kilometers apart we need to launch 11 segments to fully bridge the gap as you can imagine this was a time consuming process each launch took about 25 minutes due to the lag so already the launches took 5 hours to do on their own in total getting all the segments to trace and landing them took a total of 13 and a half hours while this sounds like a lot this isn't actually too bad for one of my missions for example in my previous video where i flew a long range aircraft it took me over 21 hours just to finish the flight with the segments in orbit the next step is to send the convoy off to dress again the dress transfer is not exciting one thing i'd like to mention though is that i'm using the rcs translation controls to fine tune my encounters since the bridge segments are so long their rotation rate is painfully slow so it's much nicer to use the rcs for these small adjustments instead of rotating the whole craft now that we're at drace let's commence the landings this is going to take a while so let's speed this up as this goes along let's discuss the design of the segments first and foremost i built these segments out of the mark iii space plane fuel tanks i did this for a few reasons for one these fuel tanks have a large flat side which makes them perfect for tiling them into large flat areas like for a bridge secondly the fuel tanks are extremely sturdy they have strong attachment nodes and they have a high impact tolerance of 50 meters per second on top of this they contain fuel which of course you could burn to help transport them around there are about 200 of these fuel tanks per segment and they are arranged so that the segments will interlock nicely with each other one half of the fuel tanks is on the south side and tiled side by side to make the central bridge structure at the end of this section there is a depressed platform which future bridge segments will be landed on top of the other side of the bridge has the mark iii tanks running alongside the central bridge this arrangement is not only modular it also keeps the center of mass at the center of the segment so that it can be landed without tipping over in total the segments are about one kilometer long and extend the bridge 500 meters for each segment with this length the moment of inertia is extremely high and so the segments are very hard to maneuver and to make matters worse they need to be almost perfectly aligned for each landing to help with that i built a special landing system and landing procedure the main component of the system are two blocks of rhino engines which are placed near the center of mass and have engines to cover all the translation axes i did this so that i don't have to rotate the entire craft in order to land it instead i can simply toggle the appropriate engine cluster with an action group to cancel out my velocity for fine tuning and attitude control i added several pods of rcs thrusters along the length of the segment for controlling the alignment i'm using mechjeb's smart ass to point upward and hold a specific roll angle by doing all this i can ensure that each bridge segment comes in with the correct orientation which makes landing a much nicer experience one final note about the structure it is very important for these segments to be as rigid as possible to take the stresses of landing to get the stiffness i needed i used a technique that i call auto strut noding for those unfamiliar with auto struts auto struts are an advanced option that can be enabled through the advanced tweakables and the settings menu with auto struts you can create invisible struts that link parts together increasing rigidity and hopefully eliminating crack and attacks that come from wobbly joints auto struts come in three flavors root part grandparent and heaviest by cycling through these auto struts in the vab you can see how they form connections the most useful of these for this case is the heaviest autostruts in my technique of autostreat noding you create a group of heavy parts somewhere on the craft placed in symmetry when you enable heaviest autostrut on the other parts of the craft they will all link up to this group of heavy parts which forms a very rigid structure on the bridge that's what the four tanks in the middle are for they are each filled with fuel and locked so that they remain the heaviest parts on the craft and so all the heaviest auto struts link to them and look at that the bridge is finished now look at that tight fit the last segment fit on with only a tiny amount of clearance at this point though i realized that i made a mistake i didn't bring enough segments you see the main bridge reaches all the way but the side segments do not so we need another segment to finish this off yeah you know the drill i'll quickly skip through this okay there we are the main bridge is now finished the last thing we need are ramps to get on and off the bridge let's launch them again there's nothing really too special about this process so i'll quickly skip through this so now that we are landed you'll see that this is nowhere close to actually fitting on the bridge that's all right though we have a trick let's remove the auto struts on the ramp pieces and watch what happens when i do this the ramp sections become floppy and fall to the ground while they don't look like they are attached they are still in fact attached to the main craft what's going on here this trick is something known as bendy tech basically i have a stack of ant engines inside the craft that the ramps are all attached to these joints are incredibly flexible and so the ramps can sag all the way down letting the main platform rest on the bridge if you want to learn more about it check out the link in the description there's lots of practical applications for this tech that you can explore that said this is still looking incredibly useless you certainly can't drive up this here's where the last part of the trip comes in we're just gonna go to the tracking station and then load in our scout rover and there you have it magic okay it's not really magic it's just how ksp handles craft loading again ksp doesn't save part deflections so when the craft was unloaded the joints snapped back to their original positions clipping the mark iii tanks straight through the ground however we're not getting any collisions here since the root part is over 200 meters away from the bridge and so the physics is not loaded for it and the mark iii tanks stay in place let's quickly set up the other ramp as well using the same procedure and with that we are finished the bridge stands at 5.5 kilometers long and reaches a maximum height of 2.4 kilometers above the canyon floor in total the bridge is over 3 000 parts however since physics aren't being loaded the performance around the bridge is still surprisingly good i'm not speeding up the footage here this is my actual frame rate setting this bridge up was a ton of work so now it's time to have some fun with it let's send our first vehicle over the bridge for that i want to give special thanks to my patron golden dragon for contributing this electric motorcycle here [Music] and with that there's the first vehicle to cross the dress canyon using a bridge the bridge makes a good runway too this craft here doesn't have enough thrust to take off normally but using the bridge it can [Music] the bridge can support some large rovers too this one masses in at over 100 tons and has a width of 10 meters [Music] i can't have all the fun so i gave the bridge to my patrons to play with too special thanks to hodiak for playing around and getting this footage here [Music] finally this wouldn't be ksp without some explosions so let's demolish it all we have to do is install physics range extender and watch the fireworks by having it load physics for all the segments [Music] now that was spectacular don't worry though i still have a quick save of the bridge to go back to speaking of which if you want to play with the bridge yourself go to the description and download the quicksave well i think that's all i have for you for now thanks for coming along this bridge building adventure with me and i hope i'll see you in the next video see you then you

Channel: Stratzenblitz75

Views: 461,474

Keywords:

Id: D_Ec3K7lx_4

Length: 19min 41sec (1181 seconds)

Published: Fri Jan 15 2021

Reddit Comments

[u/Vetinari_]

This is so insanely, ridiculously impressive. And its not just some rickety girder connection, it is an actual highway. I am continuously amazed by what he manages to build.

[u/DaviSDFalcao]

We should try those methods in real life, maybe we can find the simulation limit

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PS: i saw this video, and i need to say, this dude is incredible.

also, using Rhinos as RCS is pretty mental

[u/BrianWantsTruth]

That crosshair part, for alignment is brilliant.

[u/[deleted]]

Dres canyon bridge is no longer impossible!

[u/Bozotic]

Span Dres Canyon with this one weird trick!

I certainly thought it was impossible.

[u/The_Celestrial]

This son of a bitch actually did it.

[u/ThatsKev4u]

Engineering at its finest!

[u/Occam_Toothbrush]

I can only offset parts 20m. Not sure the trick to offsetting them fully out of physics range.

[u/ThexLoneWolf]

Beat that, u/Space_Scumbag.