VR-Mess/research/sources/nimso-transcripts/TOmVCvpq5QM.txt

# How It Works 2 B - Half Life : Alyx - Physics Design! (TOmVCvpq5QM, 1682s)

it's me name sony welcome back to vr we are back in the how it works series this is episode 2 part two and um today we are looking once again on uh grab objects we're gonna ignore everything in this little area here for now and hop over to another special place where we can shoot something yes we have guns in this video and we also have the gravity gloves yay um now we're gonna continue on from the last video so if you haven't had a look at the last video yet uh have a look at that first uh because that one describes a few things that we're going to base some of the changes off here as well so let's have a look very quickly let's get over to where i want to go now one thing very quickly i i did notice is if we just push our hands through here you can see that uh there is no uh no enemy over here or anything there's no head crab or anything there's just that that dude over there which is of course unusual since if we open this door over here and pop back up here you can see nothing there even if we pop our head into there nothing there however now we uh suddenly have this dude so yeah you can see exactly when that loading point happens it actually happens right as you come around the corner he gets loaded in so that way you don't have a chance to actually see him accidentally when you pop through here now before we start we're going to take this guy and drop him over there so we don't have to look at his ugly face um let's start with something that we actually mentioned in the last video uh but before i do that i'm gonna grab that thing and put it in this pocket that's quite important we'll have a look at that very soon uh but right now guns how do guns work well in the last video i mentioned and showed how when you hold a physics object or when you're not holding a physics object and you're moving uh your hand does this intelligent thing where it traces from your head to the uh objects in front of you and persistence itself there it doesn't apply to physics objects so as a result physics objects don't end up on the front of the object that you're hitting and they just have you they have actual physics that sort of forces them to get to get delayed and pushed about that however doesn't happen on guns you can see here obviously this is what a gun would do if you pushed it into a wall however when i'm moving with the fake movement you can see it doesn't actually do that it does what the hand does so how is that happening well it's uh it's very simple really that is not a separate physics object that is the hand that's uh kind of the simple way that i would do it anyway uh now once again disclaimer i don't know any of the actual behind the scenes of any of these uh any of these things i just uh study games pretty pretty much from the moment i start playing them and uh that's how i kind of judge what i believe is happening most of the time right so yeah what's happening here is this is basically just replacing your hand when you're holding a gun your hand can't really do anything other than hold the gun at that point so it's not able to do any of the gravity glove stuff as you can see nothing with this hand here not with this hand right and they also of course can't grab things so here using my grip you can hear it in my hand absolutely does not grab objects so all they do basically is just change the shape of your actual physics hand remember the physics hand isn't the one that you're seeing right because if i'm holding something and then i can i i sort of stop that thing there uh that's not very useful to do it there um not that one of those boxes once again right remember if i'm holding something like this i still have a physics hand which is completely separate which allows me to push things about right so that visual hand is not what you're actually it's not where the actual physics is and the same thing applies here and in fact this is actually a little bit offset from where the hand really is in reality i don't know whether you can see if i yeah you can see it if i pause the game as well so here we go i need to keep moving my headset down i keep forgetting that the camera on screen is a little bit stupidly positioned uh but yeah there we go so when we pause the game you can see that my actual hand is not in the right place and you can actually see that from something else as well here when i hold my uh my teleport line you can see it comes from the center of my palm here in between these two fingers right comes from the center of my palm there we go but when i have a gun out you can see that the teleport line no longer comes from the center of my palm but rather a sort of lower area right and that's just it's just an offset entirely designed for the gun to be positioned in what feels comfortable you'll notice that's actually a very common theme here with what we're talking about today which is how the game decides how to deal with physics objects it's very important to understand that a lot of this pretty much everything in this game is design decision nothing's left to chance or at least most of the things are not left to chance and we're going to really show that here by taking all of these random objects off this table including that radio just because i want to right and we're going to separate this thing from its computer right oh that was a very frustrating thing i just did right there we go um i'm gonna have to do it doesn't matter we're gonna move this computer over here and nope can't grab it with two hands there we go right get this out of the way now what i'm going to say here is wait how does weight how is weight handled in this game as you know i mentioned in the last video that some objects allow me to hold them with two hands however if i hold them with one hand the game just detaches me automatically let me put that back there i don't want to see your ugly face yet and um yeah so the thing with some of these objects is some of them are too heavy to lift with one hat as you can see that's the case with this monitor i try and pick it up it just drops right and you can see my grips are still held there we go and of course when i hold it with two hands i can lift it right because this object is nice and heavy and too heavy for me to lift with one hand this object is too heavy for me to lift at all so i can't lift it with one hand as you know it's really weird how it's actually off setting um i also can't lift it with two hands as you can see right but that's actually not true it's not based on weight that's the thing what i found is that it's it's actually not based on weight for any object not just these specific ones but nothing at all and we can show that by giving this thing a little bit of a punch let's do that shall we there we go beautiful and now you can see firstly i can distance grab it secondly i can grab it with one hand that is some heavy glass right there yeah so i just have to punch it and break it and this applies to pretty much any object that can be broken if you can't lift it if it's too heavy there's some radios early on in the game as well but you can you can't pick them up with one hand but you just have to punch them break them and now suddenly you can so here we go this object i couldn't pick up with one hand and now i can i can pick it up with one hand because i broke it this object i couldn't pick up at all not even with two hands so what i like to do here is place these objects together and you'll see something almost straight away which is let me just uh do a fake stand up there a non-fake stand up sorry and now you can see with one hand now with two so my other hand is here with one hand i'm able to not only pick up the object that i couldn't pick up with one hand but also the object that i couldn't pick up with either hand like even with two hands at the same time completely nothing to do with weight that's the thing that's what i'm trying to highlight here nothing in the game cares about actual physics right and that's intentional it's very very intentional you have to bear in mind and understand that right it's very intentional to not do things based entirely on physics because if you did that some things would feel a little bit weird because of the tracking displacement where you sort of move something and and the objects just sort of have this have have too much weight to them even though that's kind of necessary because some objects will need too much weight in order to prevent you from lifting them like these guys let's have a look at ragdolls for a moment right they're too heavy to lift at all or at least the game wants to sort of kind of make you believe that of course everyone knows that that's not the case with these guys they are actually prevented from moving right so as you can see here when we try and grab a rag doll we can't lift him right you can see with my teleport line i'm trying to move my hand up can not lift him right i teleported but what happens is is that it actually creates a joint so this joint here is being created when i grab it the thing about it is when i grab it is of cour is of course a is something that i can do multiple times with these objects right so i can grab it with one hand and then i can grab it with another hand so this joint that prevents me from actually lifting this character is actually being generated every time i grab it even if the object wasn't on the floor so even though i can't lift this guy i can very easily keep moving and keep grabbing and re-grabbing and suddenly he's just sort of hovering in air watch this i'm holding him with one with his foot and his joint now which prevents me from moving him around is actually there hovering him about so i'm able to just sort of pick him up with a leg and make him nice and fly right and the other thing you'll notice is he seems a little bit light again it's intentional design the game doesn't really bother with the physics it doesn't want to it's intentional that's the point it just wants you to feel like everything feels quite right right and that's why it's very easy for me even though i can't actually lift these things with one hand look there we go it releases as soon as it's off the ground even though i can't lift them with one hand i can do this right grab i can throw them really easily with one hand because they're not actually that heavy they're totally they are designed to release based on whether you've got you're using one hand using two hands and that works the other way around as well some objects like uh that thing for example can't hold it with one hand you can you can't hold it with two hands you can only hold it with one hand right even though technically you know those two grab points don't interfere with each other i can grab it but i cannot grab it with two hands again the game decides that based on it's purely based on design right nothing is ever too heavy for you to pick up because that would feel really weird and you can tell when you start filling things into an into a container like this for example right that that is the case so if you were to put like for example that and then you put this into there as well put that underneath put that on there as well and then you put this phone in there and whatever then suddenly this object becomes much more laggy to lift and it doesn't feel as good um for what they wanted it to do to feel like in the end now there's actually something other something else that's really unusual about these things right now we're gonna use this one we'll try and do this it's it's a very much a chance thing but you'll see what i'm talking about in a moment so there we go right um and what's happened here is something very unusual you can see that my hand is actually flipping up and down while i'm holding the object and i'll explain that very easily right so what's happening is this draw is actually the same physics object type as the drawers that actually end up in an actual cabinet the ones that are locked in place the ones that you can't move and if you move too far away they just detach oh oh or at least sometimes they detach you'll notice my hand jumped over from there but yeah so there we go so these objects are the same type of physics object and you can see on their handles they have this soft motion once again i'd like to remind you of the last video where i showed how the visual hand is not actually where your physics hand is which means the visual hand can do all of these extra special things in order to look much better than than just a static joint right and of course on these other corners of the object where you hold it that doesn't happen the visual hand just stays in one spot and there's no soft motion on the handle however there's this nice soft motion and of course the game doesn't really care whether you flip your hand around uh it just sort of lets you do that instantly rather than rather than making you detach and reattach to the handle it just sort of does this this is entirely animated right here right so you can see it's a soft position the same thing is actually happening here and you can see that my hand is able to very very easily like softly more move around on this handle there's actually a proper grab handle on here that's a proper physics handle but it's uh it's sometimes being ignored sometimes the game sort of accidentally uses the thing that shouldn't shouldn't happen which is this this type of grab handle right and as a result you have this sort of weird grab point and you can actually see there's something extra weird about it which is the way that that grab point is actually oriented right now my hands are both facing each other right so this my my right hand palm is actually in this way right let me just show you watch this when i pause the game right so this is what i'm actually doing right now i forgot about that right now this is what i'm actually doing right watch what how it's positioned you see that so the grab point is actually oriented wrongly as well it's actually not wrong it's just grabbing the wrong type of grab point there's another thing you'll notice which is how there's an excess lag when i move around using the fake motion again that's because this is not physics this motion here is not physics whereas this one here is actually not tracking that because it's not supposed to you see when i move around using this it stays attached to the physics object it's not supposed to follow my tracking as i move it's supposed to move with the object which is what it's doing here except that object is not supposed to be fake moving with me so that object is fake moving with me like my hands do which is what allows me to very quickly do it however when i do the crouch thing you can see it stays in position correctly right it's only because of the fake movement that it doesn't know what to do because that grab point's never supposed to happen and you can see if i grab it normally it does actually have a proper grab point where it doesn't have that soft motion on it there is something unusual though you'll probably have noticed which you might not have noticed but you might have which is this as i grab an object you can see that my wrist pocket is rotating to keep the object in there oriented correctly right so as i turn my hand you can see this object gets oriented so that it always faces me vertically right no matter how i look no matter how much my hand rotates the same thing applies when i'm holding an object as you can see however there's something really funny because once again that wrist pocket is not based on the visual hand it's actually based on the physics hand which means if i grab this oop no doesn't work with those i need something that i can grab with two hands not that oh a box wonderful so here we go as you can see i rotate my hand and it keeps itself correctly oriented so that it's always vertical according to my head tracking well according to the world right but facing me because i can turn my head and of course it doesn't turn with me however it's not based on the visual hat because if i force my hand to rotate it's actually based on my physics hand so here we go i'm going to try and lock this object in place and you can see me rotating the wrist pocket based on my physics hand so what's actually happening here is the object is parented to this to this visual hand so it's directly affected its rotation is directly affected by this visual hand however it then locally offsets that based on which way my tracking is facing which is actually my my physics hand so it rotates that locally but it doesn't know that obviously this object is not actually rotating that much so it's offsetting locally when it doesn't need to as a result when i tilt my hand right it offsets left if i tilt my hand left it offset right in reality that would work in a normal situation i turn my hand right it offsets left right that makes sense but because i'm preventing the hand from visually doing that it does that and it would be correct if i let go so just another unusual thing about the wrist pockets well there's more to come because if we throw these things out of the way in fact we could just use these drawers it's always very easy to use these drawers uh we need that their clipboard this clipboard is really cool because we can get it stuck right throw it in here and then what we can do is put off physics hand outside right so you can see here now i've got a wrist pocket here except i don't right because let's let's uh let's let's position this nice and easily here we go and you can see that my wrist pocket doesn't seem to work that's because my physics hand is actually over here so if i put my hand now behind my actual wrist you can see that the wrist pocket while it visually stays on my animated hand is actually calculated based on my physics hand so here we go i can just move the physics hand anywhere and it detaches because there's a distance limit on how much we can grab these things right so there you go you could see that the actual wrist pocket is also not based on the visual hand the functionality of the wrist pocket is actually based on this physics hand right so i can take it out and i can put it in you see that very cool because it's always based on the physics and the physics hand is sort of treated like tracking in most cases that kind of covers most of the grab systems we also have one fun thing which is when we actually do a pull what we can do is accidentally the game doesn't really realize that i've released the grip because there's actually some certain frames where the game doesn't check for my grip as a result i'm not actually pressing the grip button right now so i'm gonna hang this i'm going to hang this controller or in fact i'm just going to place the controller on my laptop right now there we go place the controller on my laptop and you can see my hand is not there we go it released it it eventually releases it but yeah it's very cool i can't just sort of do that and there we go i can just hold the object even though i'm not holding the grip button right so there's a little bit of a weirdness going on that's because there's a momentary time where these objects are not actually are not actually running the grab system they kind of don't care very much and what's cool is that there's more to it than that there's an animated portion of that where it also applies forces so what you can do is you can actually do a pull and then rotate your hand and it applies that rotational force which is really cool let's look a little bit more into how the ground pull actually works so we are supposed to do this supposed to point our hand towards the thing target it by using either my grip or trigger index trigger and then pull right with our hands well actually you don't really need to do that you see what happens is the game doesn't care about the direction of your velocity it just cares about the velocity right the actual speed so instead of doing this and pulling our hand up what we could do is pull our hand down or we can pull our hand right or we can pull our hand left or even we can push our hand forward it doesn't care about the rest of that it doesn't care about direction it cares about the speed at which you're moving your hand in any direction right and again that's a really brilliant accessibility feature because even though it feels really good everyone's sort of talking about how oh this feels really amazing it seems to always work yeah well it's actually very simple guys check this out it just does based on your hand your hand speed it doesn't care what direction you're going it doesn't care what you actually do with your hand and the same thing applies to something else as well there are other things which require you to to perform a hand gesture to actually do a nice motion on them and they do exactly the same thing you see i can't just move my hand right or left it doesn't care whether i go up or down or left or right you see that it's all not based on the actual direction of my movement but rather just the speed of it we've got one more thing to have a look at and then hopefully end this video because it's probably even longer than the first one that's okay it's all fine and that thing that we're going to look at now sometimes happens and sometimes doesn't it's likely to happen the first time you grab an object so it happened it happened let's have a look at this suitcase how am i grabbing it like this well the answer is i'm not you see the actual physics point that i'm grabbing it at is here right again you can see where my tracking is because nothing's stopping the object from being pulled around if i pulled it then the tracking would be separated right because that's actually a physics hand what's happening here is for some reason i need to jump into those things that's not very good for some reason the game is moving the object based uh positioning my visual hand right in a different place and i believe what's happening is that the game just simply doesn't know it doesn't always have the right code for when dealing with ragdoll objects like this so this is a jointed object this is a ragdoll object the same thing sometimes applies to any ragdoll object right and what's happening it just seems to have calculated the wrong offset even though the grab physics is actually gone to the correct offset the visual hand simply hasn't again that wrist pocket is not there but rather on my physics app right which of course can be moved out of the way as well if i got this stuck somewhere without breaking my controllers then it would be really cool well there's a little bit more to it than that as you can see you can you can distance grab objects this needs to be emptied there we go you can distance grab objects that aren't ragdolls however the ones that are you can't distance grab them can you see this same box over there it's because it's a ragdoll you can see it's got all these jointed pieces right all these folds and stuff there's actually something completely different between these two not just the fact that it's a rug dog but one of them seems to be on a very weird physics layer it has different collisions watch this this one goes through my head and the game doesn't care when my head's inside it this one it actually you can hear hitting my head right it actually collides with my head and the game hides hides my vision while i'm inside it it's it's it's very unusual there's so many physics objects in here where because they're jointed because they're ragdoll firstly i can't pull grab them right even though they're the same box and sometimes as soon as i grab them the offset will be weird i bet you if i grab that suitcase now for some reason the offset will be fine right it just sometimes does it and sometimes doesn't i don't know the game just doesn't seem to like rag dolls or jointed physics objects for some reason which is very unusual anyways i'm probably probably going to leave this video here again you can see that there's a ragdoll object there because i can't pull grab it there we go and yeah i'm going to leave the video here i'm sorry if it took a little bit of rambling here there and everywhere once again i always do that now once again i have um i have begun recreating the mechanics for this next video as well so i have already done the the physics hands and the sort of tracking fakery thing here and replicated that based on these uh based on things that i've said in this video and i'll be showing that in the next video hopefully thanks very much for watching i know it's been a long one good bye