CitizenCon 2948 - Panel: Breathing Life Into Content With Physics

Transcript — every row opens the video at that moment

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   please welcome technical director Shawn Tracy and senior tools programmer Andres roar well great uh thanks a lot for coming guys star citizen citizen Khan 2948 so I've been doing these for a few years so it's pretty fun and I'm super happy that you guys came to our talk because who cares about spaceships and his face game right exactly let's hear about content in physics and cloth simulations and all those manners of things so before we get too far I just want to introduce myself and Andreas for those that don't know me I'm Shaun Tracy the technical director of content at cloud Imperium games and with me on stage today is Andreas roar he's one of our senior tools programmers out

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   of Frankfurt so thanks a lot for flying all the way out from Frankfurt he works very close with our engine guys on a lot of the stuff that we're gonna show you today so really happy to have him here with us today all right so let's dive right in now there's a bit of an introduction I want to talk about what we're actually gonna do here so environments and even characters in some cases within start system have arguably been a bit static and recently the physics engine and game teams have been making a really concerted effort into helping bring some life into basically all our scenes and with our content using physics on our assets so this talk is gonna cover some of the work that they've been doing and some of the features that aren't in design are now able to start using within star citizen and squadron 42 so before I get too far I really want to give a big shout out to

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   the guys that have actually done this work and allowed us to kind of represent it in and show you guys today cuz this is super early stuff we've only been kind of having this online in the last let's say month and a half two months or so so I'm really happy for guys like Chris rein and the physics gurus over in Frankfurt to kind of let us show you this in a very early state they were quite nervous obviously about that I'm a little crazy I want to show you guys all the stuff all the time but of course this is really important that I give them a really nice shout out and it's really we're really lucky to be able to kind of stand up here in rep those guys okay so let's actually talk about what we're gonna talk about the talk is split into two sections first we're gonna talk about environments and this is gonna include things like planet wind we're gonna talk about the wind entity which is something new for us

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   we're gonna talk about kind of an animated asset or content versus a simulated asset so doing physics to move it around or basically having some sort of pre-camp animation then we're gonna talk about environment cloth itself so this is our entity cloth we call it then after that I'm gonna pass it over to Andres and he's gonna talk about character cloth now this is unified now with our environment tech and this wasn't the case up until now then we're going to show you a bit of a demonstration with the implementation that we use right now because obviously you do have cloth on characters and stuff in the game already but it's a pendulum simulation versus a vertex simulation just show you guys the differences between the two will show you better the actual workflow that we're using and that he's still developing right now so that you know the artist can work on this a little bit

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   faster and then we'll show you a little demonstration of a multi-layered cloth so this is the thing that we couldn't really achieve before this kind of content and then finally we'll talk about some of the physics of the future yes yeah that's a nice one we can sell that one all right so why do we want to simulate things physically now using physics simulation at runtimes and games is often preferable to using sort of pre baked animations especially when placed in dynamic environments so what do I mean by a dynamic environment dynamic weather and wind it needs to kind of support things like weather effects you need to be able to do player collision you need to be able to react to explosions that are nearby you need to be able to react to AI collisions all kinds of things that will change around it so you can't just pre cannon

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   animation as I did do that you'd rather simulate that physically but there's problems with that obviously comes performance implications and things like this so we had to solve all of these so generally when activity is going on near the objects it should be reacting appropriately the other thing to why to use these physics is actually content creation itself becomes way way easier when we have to make an asset that's just simply it actually goes through a lot of teams so it goes from design to art to rigging to animation back to design and finally in the game that's a lot of people to go through and especially when you're in a an international corporation that that's got to go through time zones that takes a while instead of just having a designer take an asset and it's ready to go so what has been the state of of simulating such assets for us up until now well it's been really expensive as I

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   mentioned in terms of performance and generally relied on Lua now if you've been keeping track of our object containers streaming work you'll know that we had to remove Lua completely from the engine this was a huge deal to do and what that meant was things that were previously working before didn't work at all anymore so you know it's not that this isn't revolutionary by any stretch but we did have access to similar things but there were big assumptions that those older entities were making and the biggest assumptions of the pre-existing entities were things like assuming setup like dead is always going to be up or Z I'm sorry it's done Canadian and ultimately they hadn't changed much since earlier versions the entrance so they just weren't suitable at our scale nor for the performance implications that we have so we'd

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   already tried a few techniques previously but they've even proved too expensive that I'm sure you've seen them within demos you know tarps floating the wind flags and things like this they were either too expensive to run on a planet or the tools and entities just didn't work anymore so generally we didn't really have a planetside location that needed a lot of this so it wasn't as big of a deal but now with Hurston as you've seen there's wind there's atmosphere there's lots of stuff going on near these objects so it's very important that we brought this online so and again thanks to our amazing work biophysics crews back in Frankfurt that new implementations are now usable by art and design for things like constraints soft bodies environment cloth and last but not least character cloth alright so as you saw already in the demo we have wind on planets so even

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   tweakable to each of the planets and even to each of the ecosystems which is really cool so this was created by our planet technology team this helps gives tons more movement and life to otherwise the static environment if you saw those trees just sitting there not moving at all it would take you back to the you know early 2000 even early 90s of games where the stuff just didn't move around as mentioned previously this whole wind system it did exist that we had wind four levels but again this would only this needed to be rewritten to work in a non flat 2d world basically this is actually you know involved around the sphere so the the wind in the end has to be relative to this a spherical position on the planet so you can imagine how that's actually a little bit difficult so changes were mostly related to making that whip work in 3d on a sphere so the

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    second type of win well I'm sorry let me show you a quick video here so this is the savanna biome that you saw a little bit of I'm actually right behind I'm sorry right in front of the crashed crashed satellite in this particular video and I just wanted to do a quick pad because you see how much life already that brings so you see leaves moving in the wind you see it affecting the particles you see it affecting the grass and again this is the wind flowing through this just happens so now again this is set on a per biome level but even at a per biome level that scale is pretty gigantic so now on a much more isolated level we have a new type of wind um that that all mixes in with in the planet wind it supported it's called the wind area entity so this is what you see an image of here and here so the

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    wind area itself physically simulates the air with a given resistance viscosity and it moves in a user-defined direction at a user-defined speed and users meaning the designers basically they can select this entity and set all of these things really really quickly so generally if no direction is set the wind source moves omnidirectional II and that's what you see on this image here it's actually a sphere of wind so this is all emanating from a single point outwards and then if you give it a direction you can see that we have these nice little debug arrows and that's gonna actually give it a very specific direction that it is so this gives the designers the ability to actually localize their wind a lot more realistically the other thing we do with these is we like to attach them to things those things like the back of the ship for example if you got thrusters and things like that so both of these eventually need to work into the wet

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    weather system that Chris Roberts is obviously very keen for us to start working on but these are the stepping stones into something like this okay so let's talk a little bit about an animated cloth versus this new extended cloth entity so sometimes animation is suitable to do especially if the players not going to be near it or nobody's gonna really affect it but again it kind of has to go through a lot of people so it's really it's not that great because it's not affected by dynamics in the end so let me show you a quick example of that going on so on the left on the left sorry we have a pre-baked one now all these little gizmos you see there are actually joined so there's like there's 30 40 joints moving this around now these two tarps are actually placed on boxes I removed the boxes obviously so it takes a certain amount of markup to still get

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    our entity cloth reacting to this I've also got now a wind entity that we just talked about and I'm gonna move it over the dynamic one the video pause I'm sorry I got excited and I clicked on it so you see as it moves around that actually reacts very realistically to it and again it's it's marked up as if it's on boxes and we do this just with vertex colors so we can make an asset we can mark it up and as you see when I move the wind entity over the animated object nothing happens right because this is just a pre-canned animation doing the same thing and this will collide with players this will move into any-any the wind direction changes and you as you see I'm just pulling it all over it so if any explosion happens is there any if anything dynamic happens it's gonna react appropriately so that sort of

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    gives you a good example of look there we go sorry a good example of why sometimes you want to make this dynamic rather than rather than pre can sort of animation and again it saves on our joints saves on animation saves on a lot of work so let's show a couple of the features of this extended cloth entity so this is kind of a fun thing now our physics group Chris rain really really wanted us to do this really nice sort of ship reveal with a nice satin cloth and everything but we had a lot work to do for this demo and some other stuff later on so it's close its close to what he wanted I hope I hope he's happy with it so the physics team similar to the Rin had to rewrite this cloth entity implementation completely from scratch it was really important because we had some trouble with earlier versions and it's not only that it didn't work on at

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    the scale of planets and assumed things like set up but there was there was other problems with the earlier implementations within the engine anyways and most of the most these problems related to instabilities within the simulation and what that would cause is something called we kind of call it poly soup it's like a big ball of polygons that just can't recover from the simulation so you can't ship a game with that kind of stuff if we shipped it out to and who had an interaction like that I mean that that's not acceptable to us so we had to change that so major culprits of the poly soup are usually the topology of the asset itself and without going too deep into it the geometry being simulated has to be really regular faces or the the face areas have to be the same otherwise you'd end up with this sort of poly soup ball ultimately the issue was that the topology of the render mesh and the

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    simulation itself were were coupled so basically whatever your render mesh topology was that was how it was gonna simulate we've decoupled that now lastly we didn't have self collision before so cloth couldn't collide with itself that's an important component because it means you can have freely flowing cloth meaning not attached to anything you've probably seen it in a million games they have you know some tapestry up on the wall or just something hanging from something and very seldom do you ever see free-flowing cloth just moving around soft body in the world so let's get this video going cuz I'm already going over time sorry all right so I've got a quick video I just threw an M 50 down on damar and I got a couple deck crew taking care of it I was getting lonely so you see I spawn up this cloth and it keeps pausing sorry about that I spun the cloth in and I just turned on

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    our AI physics and basically physics starts simulating and that drapes over the ship just as you would expect it to so now I keep playing around with it a little bit and there's so many different properties actually exposed directly to the designers for something like that so I need to mention that this is of hyper fish and simulation and there's a certain amount of it's a user-defined variable for friction right so we can pull the ship out and I can change the friction so that that thing will slide right off or it will kind of hold on to it but now I'm gonna do something a little more extreme and this is where you really need the self collision so there you can see it fold up upon itself and we're gonna run it again just to

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    show you again this is it never gets to a state that it can't recover in terms of the simulation and it's always going it's a purely deterministic simulation regardless of the frame rate and time step size which is a big big deal for us it's also unconditionally stable so it's never gonna explode and will fully recover so when I mentioned those wind entities before and sort of attaching them to the back of the ships and I was just wiggling it around under it just to show you how how dynamic that stuff actually is so let's say you had I don't know a little flag on the ship or you know you might have a Superman ship with the cape on it who knows so I dropped it on the back and I've got a little wind entity actually attached to the back so let's turn on the ship and it blows off onto these poor guys back there so we'll

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    do that one more time because I don't know they need it so now you can see their heads poking through that was my fault actually on the topology of the asset itself it just need to be a little bit tighter for collision and you can see that that wind is still going on in to flutters down on to the point nicely so I'm going a little bit over time so I'm not gonna go over a too deep of the other things but again this is early times you guys are gonna see tons of this now within the environments and yeah I'll pass it over andreas who I sucked up two minutes of your time I am so sorry that's not gonna be a problem thanks Ron alright so I'm gonna talk about character cloth as Shaun has told you of the soul had been rewritten completely from scratch and previously we've had two different pipelines two different solvers and that's always like a pain in there it's a big pain to maintain these

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    two it needs like separate teams to do that and like yeah so the unification is really a big deal for us and the let me tell you a little bit more about how the previous system worked that sean has mentioned this so called pendulum simulation so imagine like the characters called our characters in the game they have this internal skeleton which is made up of joints or bones as they're called and these pendulums are essentially extensions of these skeletons so there they were used primarily to attach more kind of rigid they're like simple orbit objects like for instance grenades attach them to a body or like a rocket launcher at you at the back of your back and whenever you moved this this stuff like wiggled slightly around and it wasn't originally not really supposed to be used for more

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    complex simulating more complex types of objects such as cloth shirts capes trench coats whatever so what they did was like in earlier titles that used the system they created ropes of these basically joined chains and created several of them and connected them together so they would form something like a sheet of cloth but the real resolution of these things I was always very very course so I've always liked in terms of like fidelity and now with with this vertex cloth approach you have the ability to put a lot more detail into these meshes and that results in much better looking simulations so as you can see here website is which shows vertex closure the new stuff is is on the left

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    and you can see like you can see all these wrinkles going on creases fold folds forming dynamically reacting to the animation of the player the thing is like in general in terms of character cloth the problem with character cloth is that the characters are much more dynamic than environments so even though with a new cloth our environment cloth can be more dynamic and can move move about in the environment theoretically Merilee it will be curtains or tarps flags this kind of stuff across on a character needs to undergo much more stress because who knows what the player ends up doing with the character they jump out of their ship and expect to land somewhere and that cloth still looking nice and neat so for for the physic solver that's like very demanding

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    so we're quite happy that this new solver is very stable it doesn't explode sometimes like for more extreme cases you need to help this over a little bit and that's why we have these mark-up tools for so I worked in the film industry on cloth simulation and soft body simulation for a couple of number of years and in the film industry there is this well the industry standard there is digital content creation package and called Maya and that inside has a solver that's called ncloth and yeah so this this particular solver is kind of the industry standard it's quite robust it's easy to author and so my idea was instead of creating new authoring tools

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    within our sandbox editor which is a significant amount of work to do that lets just use Maya because for instance all our character rigs are already altered in Maya the character animations are altered they're all the like character assets are put together in Maya and then export it and it paused again so that's why it made all kinds of sense to to also do the cloth setup authoring there and what you can see here is scrub through real quick by painting these what we call vertex attributes you can define for instance how in how far like the cloth is attached to the rigidly deforming mesh and by doing that you can kind of guide the simulation in places

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    where you know that it's gonna be like there could be problems when it gets pushed between collision objects for instance and then even the most stable simulation could run into problems it paused it has its own will for some reason so in this case I altered it in a way so that it like the attributes that you can use are exactly like a mirror of this ncloth tool that you can have in Maya and the reason for that is that artists can already use a tool that they're familiar with they can order it in exactly the same way the even they like the words the descriptions of the attributes are the same and that way I think they can be much more productive so the previous the main problem with the previous system is the most know was that like

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    the authoring part was very cumbersome and very limiting and through this system we're gonna be able to create the most complex of setups that I think you have seen in games Shawn is already shown or we've already seen a the example of the trench coat on Bishop but the real deal is like this what we call layered cloth where were you have like separate different layers of cloth interacting with each other and so that's what I'm going to show you next so it's probably the worst case example of what you can have so here that's that's some that's not the final product but yes I think when you're physic programmer and you you've been working

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    on your code for so long the first moment you see stuff like that it's like there's super happy because that's already a big breakthrough we've coded these individual sheets so we can see where they interpenetrate if they do but it's already pretty clean and I was one of the first tests we did so Chris Wayne has clearly done this tremendous job there [Applause] so that is one of the Hurston security guards I think and yeah it's just amazing how complex this stuff is and it's still it still looks like impeccable looks similar to like an offline cloth simulation and ultimately with the system what I'd like to do is like simulate as many objects as we can

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    like currently most of these like more like dangling free hanging cloth things are simulated but there are other things like even if you have like trousers that are in super tight if even if those have like a tiny amount of degree of freedom to move and your entire animation will look more dynamic and more more believable and if we can end up doing this on the entire body I think we'll have really like amazing looking characters in the future right so talking about future yeah sean is going to give you a bit of an overview of what's what's coming up next sure I'll just let that one play out here I was manually looping that last bit there yeah and there was this was some great work literally in the last

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    week from some super good tech artists gage Holloman Marcy Lee Chris and Forrest as well as the physics programmers helping them out so of course rain and the physics team they're so big big props to them for doing this that was the idea so the comment was no clip indefinitely and that's the whole idea of that there's self collision that we can do that layered cloth and it's not necessarily something that we could do with pendulum cloth before so it's gonna let us kind of do the Queen Amidala cape dragon on the ground going down the stairs and these kind of things that's gonna be pretty awesome so some of the future stuff that the physics guys are okay with us kind of mentioning a little bit is something called the for mobiles this might be something we're it's this is all Rd and kind of you know hopefully we can do this but this was

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    something we tried out in one of the early games on an earlier implementation the engine deformable is something that will react to an explosion force and the easiest way that I've ever had to explain it is like imagine it's simulating like a cloth or a single frame so that once something deforms and it holds ridges so we could deform things like sides of the ships sides buildings doors train containers whatever whatever you can things out so drink containers on sea containers yeah well no those trades in Hurston we're good further performance improvements it's already orders of magnitude faster than what we had before so this is gonna be very very accomplishable within the game and you guys will see it quite soon tessellation so even getting further a basically density on those on those assets that you see something we mentioned a little

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    bit called signed distance fields that's something I was hoping we could talk about today not quite ready to talk about it this something we're gonna do to massively optimize collisions and to do some work basically with effects like shields and things to just make them conform a little bit more into the ship's it's gonna be quite nice tearing so imagine that cloth being able to tear maybe shoot some holes in it that'll be quite cool and then even better and this is something that's on line not quite ready to show it but our soft bodies and soft bodies not just a cloth soft bodies something that has volume but is squishy so like a pillow or like a duvet or something like this so then on top of that we want soft body - soft body collisions of course so that'll be quite cool and many more things that I'm sure are sitting in their brain that will that will come up yeah of course

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    so with that with that we want to give some big special thanks in alphabetical order so that - Ali Brown director of graphics programming Chris rain as I mentioned senior I I'm actually not sure but it's ty Lee's physical that's fine math wizard gage Hallman tech artists on the cloth for Steph and help with the captures Evo heard Sagan you know implemented that pendulum simulation that we are sitting there talking crap about yen's Lind game play engineer Milan paycheck helped us all with the management of this presentation Marcy Lee one of the tech artists doing the work on the asset Rob diction and tech artist in the UK also working on the asset and then Thomas make Michalik the help so big special thanks to those

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    guys for helping us do this talk basically under pressure definitely so thanks for the time guys really appreciate you coming