Gadgetory

we're going to do just a quick intro for the new folks and then probably take a deeper dive on the topic of blueprints famous writer in seven so here goes act hey folks so uh yeah the sack parish i work for epic games i'm a tech artist basically to play with the tools all the time so here's the deal right we got 40 maybe 45 minutes before i'm proud that boy give it a hook out at that point so what I'm thinking is that there's actually since you got probably know what using this there are some YouTube videos out there they give kind of a base level intro the same thing under to GDC in the matter of fact syndicate in about an hour ago so I'd like to just jump in and do some cool things in blueprint which is a village enforce visual scripting system how many programmers do i have in the room right now i'm not sure if you guys are going to tell you what's about to happen really so blueprint is visual scripting how many of you as programmers audibly grown whenever you hear visual scripting it's okay a lot of media exactly there's a really i could have done that in line of code right i always get that like i'll make accomplished thing every blue printer for kismet i'm using Yui 3 and like that a program always come by and have the same thing they're living I could have done that in two months ago and that's okay we embrace that the point of the fact of the matter is it an unreal engine 4 we realized that there are a lot of people out there who want to make games and not all of them have CS degrees and not all of them know how c++ work so you might be like me in the idea oh it scares the living hell out of you and you have nightmares about it so that's why we have blueprint what I'd like to do is do some cruel things in blue crit but I have an option for you guys you guys may feel a little bit interactive I have something that is fairly useful and involves interactivity on characters and have something that is kind of bizarre and fun so who wants somewhat useful who wants bizarre and fun okay we'll go with his arm fun and if we have time we'll come back and read movie so let's see here let's start off we're going to make our own game project currently I'm in a project that already exists if you mean for let's just do our own thing I'm going to readjust my very crazy workspace is that going to work I look that extra cabling is possible so 500 let's do a whole new project of our very own and if you haven't yet how many people have played with you before a little bit so far oh my god that's huge i love that how many people are going to i want everyone else's hand i right okay screw in the project when you create a new project you get the project browser and you're going to see a variety of different templates that you can choose from if you want kind of a head start in a certain genre me so you can see things like first person you'll see side scrollers their personal they've got more of these on the way we're back slip ups release it at least one more and more that we're planning so eat with each one of these genres that you'll notice there are two versions like if you take a look at first person here we have a blueprint first person and we have a code first person so if you're a C++ programmer and have visual studio installed it can be the freak spreads addition if you don't have Pro you can use the code version and everything that you do all the things that access to our right there in c++ code for you make it adds to them if you're not coder me and you can make the blueprint version where the exact same thing has been done with the exact same functionality operate the same way but it's been done visually employed which is what we're going to look at so let's call this my awesome projects because I'm super clever with my names on it create now there's a little check box there that says include starter content that's just going to give me some basic materials and some meshes to play around with if I want to do that a little bit later so here we are in my first person template game I could reach up i can hit play and who i turn the sound off earlier let me let me fix it we also try not to death in people because I might well that's a little bit so first person template ready straightforward you get a character of course you get a little gun here you get some project idols and even that is strangely satisfying somehow so what I want to do is I want to create kind of a random bizarre effect we're going to rain in physics objects down from the sky so it's actually gets to cover some random spawning stuff we're going to do some stuff with variable materials that you need a randomization effect and I thought a lot about what we should actually use to rain out the sky and in one of the other projects that I have access to welcome you maybe I should just show let's do it that way first off make sure I know exactly where we're going to be here in our chain or the documents project I'm totally cool with that so I'm going to jump back a project in fact what we're looking at just a second ago and bury in here is a very special assets you actually see how to migrate assets for one project to the next let's take the content browser and I'll to bring it front and center for just a moment and let's see let's do a kind of a telling search term here let's search for cows there he is I've got this little static match cap isn't he awesome foaming let's rain these down from the sky that'll make me really happy I need that kind of satisfaction so what I'm going to do is I hear the content browser just go right click on that and choose my grade and it's going to say here's all the things that that cow depends on here's all its textures all those materials all the things that make it up are going to have to migrate along with it that's good ok now it's gonna say where do you want to send that to so let's find documents with my on real projects there is my awesome project and there is this content folder so we'll select that click OK and we get a little message content migration was successful awesome so go back to our recent projects and jump back to our project it's fine by the way for all my unique a user's gone are the days where you have to do multiple installs of unique a right so you just have one install you have multiple projects that alone made me so happy so now back here in our context we can go jump into the content browser and now let's search for cow and our cow is here now let's do a couple of things with this cat first off I want to take a look at it to material so currently here's its material network it's really not super complicated we have three colors we have the base color which is kind of if this cow is white if you actually want to see this on the mesh by the way all what you can do is select the static mesh and click the set match button here in preview and now we can see our little cattle right here in the material editor so we have three colors we have white pink and grey you can kind of see how those replaced let's mess with that just a little bit so I'm going to take a spot color and I'm gonna make a slight change oh now by the way you'll notice each one of these notes has a green bar at the top I think these are parameters that means I can talk to them later using blueprint or code it's basically an aspect of material that is ready to edit we're going to take the base color and you're going to multiply it by the spot color and then we're going to make that result feed in this popular it's not going to be a really significant change in terms of our cal but what it means is if we take the base color and change it like let's say for some random example we want a stylish pink cow those spots are going to pick up just a little bit of that color so I like that idea I also like the idea of our cow going back to white at least for a little while longer okay so we're done here let's go ahead and save our changes and try i'm going to try to remember that the parameters based space color because knowing that name will be super helpful so now we have a couple of different effects there's a lot of different ways you can handle any any particular problem in code and blue cranking life whatever so i'm going to create a blueprint object that we can just write down from the sky and will populate that with a cow so let's go into my blueprints folder and I'm going to just pick an empty space will right click and create a new clip right this is going to bring up the parent class window every blueprint asset you create needs to have a parent class what is this going to instantiate from in this case we're going to choose actor actor is pretty high level it just means anything that could exist in some way in our game we have options though we could make a character blueprint or a player controller or game mode we don't need any of those two moment just choose actor we need to give this a name so we'll call this dynamic cow because he's going to be a physics object by the time we're done we'll open this up and now we need to start assembling our blueprint object now blueprint can be it's comprised of several different things or it can be as components that will make it up in this case it'll be like a static match but it could have other things to look at things like a light component to it or a sound component if we wanted to move every so often so he has some default settings he has the components that will make him up and then we have the graph which will define his behavior let's start with components obviously we need our mesh in here so I'll just make the most of my user interface let's bring up our cow over here here's the static mesh I'm just going to drag and drop that right into my components list so suddenly my blueprint has a static mesh cow perfect already changed some of the settings of that static mesh cow we're going to scroll down and one of the properties available in here is simulate physics we'll just check that make sure that's on there really i think that's about as far as we need to go right off the bat if there's if there's more than I need to do I can always jump in and do that a little bit later so now next thing we need to set up some behavior so that when this guy is born he gets a random color but here we are in the graph for this blueprint object we're going to right click and create a new event very much the way kismet was a ton religion three you can create events and actions the only catch is you have to think linearly which I'll explain here in just a moment so let's see here let's do events for begin play which is literally the moment this actor comes into being in our game then we want something to happen well we want to talk to its material we don't even know what that material is going to be and we have no direct or an easy way to access it so what we're going to do is jump over to our others are other graph X have two graphs for this object we have the construction script and we have the event breath now the construction script actually fires in the editor it's kind of like before this they never comes to intervene so let's see here we're going to take our cow so currently we have the static meshes check it out over here in components you can see here's a list of all our components and we have our one static match let me rename this just for clarity we will call this our cow mash now back here in the graph I can take that cowl mesh drag it right into the graph like so and now we can start doing things to it so let's get its material so now we have direct access to the material that was applied to the next thing I'm going to do is create a dynamic version of that material that material that we created is going to be compiled and it's going to remain static drought gameplay I want to dynamic when they can actually change during gameplay I need to make a dynamic instance that exists within this object that's what we're doing now now I hate to tell my construction script to make that happen so I'll connect my execution wire now earlier I grabbed my cow flesh we got its material and we're going to take that material and make it dynamic so really just plugging some things together some very hard and visual scripting now that we have a dynamic version there's two things I want to do I want to store it in a variable so we can talk to it again later on and I want to apply it back to our mesh so let's start with the story min here we have the note that create that dynamic version i'm just going to right-click on its return value and promote that to variable will call that dynamic material done comes easy now we just need to apply this back to the mesh itself so let's take a wire remember a little cow flesh over here we can drag a blank wire out here and say set material it's going to ask for a few things it will say what material element zero is fine is something only has one material what do we want to actually apply this dynamic version that we created a moment ago done everybody kind of see how that worked not you look still awake that makes me happy who isn't awake right now gotcha totally hear you got to put up in every you look comfy all right so we've got our events begin place and now we've got a dynamic version of this material we can grab this now we can use this to start talking to the parameters in that material so let's say we set vector parameter because that color is just a vector we need to know the name of that parameter it was base color now what value we want to give we can set this anything you want but we like something's a little bit random and to make that happen we have to know a couple of things first off you have to know that a linear color value is just a vector but it's affected with four elements we have red green blue and alpha oh my god I have audience participation this is awesome as long as you guys aren't throwing rice I'm okay front rise to your toaster a newspaper if you're getting these references thank you so much all right so what I'm going to do is I'm going to work backwards in would print the sexual in my favorite ways to work I know that I need something that will end up being a linear color so let's make one oh there we go where the note that's going to make a linear color out of four float values how are we going to handle that well let's take our first float value again we'll work backwards and let's just type the word random and we get some options so we're gonna do a random float within a range and the way our color is working on meal for rent green and blue Scalia value between 0 and 1 so we'll set in 20 max to one will take this note will duplicate it will plug each one of these into RGB and by the way of any of the programmers in the room we're kind of like well why didn't you just get a random unit vector or something like that you totally do that it just gives more vibrant colors we go this way all right so I think I think that's going to work but there's a catch right now we don't have anything actually spawning this guy just yet so let's put this guy away we're done with a dynamic how for a moment and let's build our spawning system so I'm gonna make an entirely new blueprint now let's just right-click and we'll make a new blueprint again from the class factor and we're going to call this cow spawner because that's a that's like a useful name will open this up and again we just get sort of a blank slate where we can start adding components and adding behavior and so on and so forth so the way I want to set this up is I would like there to be a three dimensional volume like a box and we will spawn our towels from random points within that box right so they can't like a volume emitter so let's start with a box probably easiest way to do this so there we go a box done now I in the editor it's going to be a little tricky because this is just a wireframe box right clicking on selecting anything that is just a wireframe can be a little bit of a pain so let's add a billboard which by the way still is the old school dragon icon from years and years ago in unreal it's one of those little things that makes me kind of heavy so let's compile that right now it doesn't do anything and let's just add it into our level I can move it up here into the air we can scale it change its size it's pretty much set to go now we just need to set up on it some behavior for it let's go into its graph and we want whatever this is going to do we want it to do this as soon as we begin playing so we will right click and again we'll say begin play so I'm going in-play we want to do something in this case we want to spawn that's blueprint that we just made for the dynamic cow so just drag a wire off of this node and let's just let that spawn and we get spawn after from class perfect we need to choose that actor so we're going to click on the little drop down here and use our search bar let's type out dynamic cow there it is cool so we're going to be spawning these and that's good now there's a few catches here we need to know where we're going to spawn it from so we need to make a random selection point within the volume of our box so what I'm going to do for starters just grab that box component which is currently in my my blueprint list there we're going to get that and let's say I don't really know what I want so let's just drag a wire off that and start trying to make things up so here I can get the expense of the box so I see if i type extent or if i could spell extent that would probably help so we have a choice we can get the scale extent of the box or the unscaled extent i know this would be really accessible to a user I want them to just be able to grab this volume dropped into a level scale it up to whatever they want and it just works so we'll grab the scale it extends to the box like so and that just gives us a vector for the X dimension the y dimension and the Z dimension so we can use that kind of as a base but we need to break it up so let's break that vector into its x y&z now we need a random range within each one of those axes so let's start there next we'll just right click and say random floats within a range and of course once again that gives us a min and a max now our extensive the boxes are just going to run positively that's just how it works so what we're going to do to make this work is we will take safety x axis will take X and make that max for the min will take x we will hit the multiply sign so we'll multiply a float by a float it'll say negative 1 so we just made a negative version of that x axis value and we'll plug that into minimum so we're going between the negative extent of the positive extent we just need to do this three more times so we can grab these two nodes ctrl-c ctrl-v control V after plugging some stuff in take Y plug it into max take Y plug it into our partner same thing crazy so I now have three random values that represents random locations along each one of these axes now I just need to make them back into a vector now there's still three disparate numbers at the moment so we can take any one of them drag a wire out and say make a vector and then just plug each number in now that gives us most of the way there there's a catch all we're getting right now is the extents of this box but we don't have an origin point we don't yet know where to start the calculation from that's pretty easy to get so we're just going to take into right click here in space actually and say get location and there's one of the things that pops up is get at your location that is where this guy's place that's where we can begin all of our our location calculations now let's just add the two together so why isn't this math stuff excited by the way who's bored yet I want to love math and I want to be good at it I can't do it either those things but I can watch my way through for this kind of stuff so there we go we're not adding these together we have a random location we have only one last thing to keep in mind that this is sort of an unreal ism or you might be familiar with the spinner how much game work you've actually done what we need is a transformed transforms not just location that location rotation and scale all together so we can take our new location have been created and let's say make transform and that's also asking for some inputs for rotation and scale we can leave those just as they are and everything would work but let's have a little bit of fun with this so for rotation we can work backwards and we can say random rotator so now each one of our cows will have a random rotation pull that I'm gold them as well and so just check that on and after scale let's work backwards again so we'll say make a vector and just like we did earlier let's do a random within range so when you decide what the largest and smallest start out and possibly be moving let's just guess we'll say small will be about from 5 largely about 1.8 we can always adjust it later and then we're going to take that same value and plug it into x y&z that will make this scale uniform I think we're pretty much done the only catch is and I realized this a little bit too late we're doing this spawn only when we begin play I think what that's going to mean is we're only going to get one cow but that's exactly what i mean so let's give it a try any minutes just play and we get our one cow but he does have a random color because it wasn't yellow before shooting which is strangely satisfying but let's change that up modify the behavior slightly so let's get rid of begin play and I wish to live right here on time lets this to on tick which means every single time the game cycles is going to spawn another count that's a bit extreme right that things we're going to get a whole lot workhouse we probably need so as a safety factor let's put with delay in here and went to is fine for starters but let's say maybe the point 05 so it's not going to be quite on every tick but will be a hell of a lot of tips let's jump in here and I can play or I can simulate let's just simulate to again oh that makes me so happy I'm sorry I'm supposed to give you a demo but I really I you guys can do that anyway moving on okay too much coffee that's what that was all right so I guess the next problem that we have is that these cows live forever which while that is kind of joyful it makes me pretty happy the catch to that is that of course over time you're going to have so many cows that your computer is going to start to slug a little bit so let's make a self destruct system you have a flow up some cows okay so here's how we're going to do this for yourself we're gonna make a new blueprint and if you are taking notes the only thing I'd like you to take this is kind of the mentality i'm using i'm gonna make a new blueprint then I'm going to call explosion Michael wondering why I outro to do that why would you make an explosion blueprint less because of explosion when you think about it several different things it's never just it's never just the visual effect an explosion is going to have sound an explosion we can it can have force we can make it have forces these are all physics objects and they have a particle effects as well anytime you need one thing to be made up of multiple bits and pieces multiple components you should be thinking in your head could this be a blueprint so let's give it that one so let's start off with the particle system we know we're going to need one now actually I got to change my mind let's start off with our sports let's do a radial force out of this so here my add components list there's stuff that I can advent at fault take a look there's a radial force now let's open this up I know you guys can't really see the screen very welcome here so to take my word that everything you see here is awesome the radius of this force let's kick that up to about 500 we can always adjust that later if you need to make it bigger or smaller impulse and for strength or would really give us our outward push right so let's see here let's say that is something really low and sensible like a million will set that for both of them you know just try to keep things nice and subdued and sensible at all times then let's see here what are we going at our our particle effect I'll be fine so let's go over the content browser and here in the game's folder so if I just search for explosion we get our little there zappy explosion here or I could just you know what I'm going to do this a different way just kind of her academic partners will spawn that actually is part of the behavior so we have our force we have we could add an audio component that'd be great so let's do audio and we need to just tell this what sound there actually is an explosion Q so that comes in with that starter content if you guys remember when i created my project will check box for starter content the explosion stuff is already in there for you play with we won't worry about multiplying the volume though I've gotta admit that is pretty tempting so let's say I now come over to our graph and we will say on the in play the moment this explosion is born what do we want to do first off we want to spawn and emitter application what location we want to give well let's say the location of this actor so we'll say get after location so wherever this explosion is we're going to spawn a particle effects what particle effects will we had you asked well the explosion effect they're also to go that was super easy well this also allows us to be automatically destroyed as soon as it's done see the auto destroyed checkbox if you can bring that from here the next thing I'm going to do is right after we're born we want to delay very briefly and then let's turn off that gigantic force that we have because if not just going to keep pushing things out and exploding just like one quick and then it's done right so we'll do a very brief delay let's say something like point 1 seconds and then we will destroy a component and since it's good it's going to ask us what do you want to destroy it we just take our radial force component that we've had it get a reference to it drag a wire off and then just type destroyed boom that's gone awesome now let's see our sound effect and I'm cheating for time right so I know my sound effect is about four seconds long so we will delay further by about four seconds will say like 3.9 because I've already delayed by like 11 and as soon as that's done we are going to destroy this actor meaning the explosion blueprint is going to kill itself and beyond so it's pretty easy network to grasp when were born we spawn a particle system we wait a second we turn off our force we waited for a couple more seconds and then we kill ourselves perfect level I just go ahead and save this compile now meanwhile back over here in our cab we're going to create a new custom event which we will call kill this cow when kill this cat was called all we really wanted to do is to spawn an actor from class now commit something what we're going to spawn exploded exactly perfect it's all in the explosion and then we will simply destroy this actor so we'll kill the cows on the explosion we have to do it another order by the way because if we kill the actor first we never get an opportunity to spawn your foot and we do need to fly a transform here so I'm just going to work backwards we're going to cheat this time going to say get after transform so wherever this cow happy to be that's where we're going to spoil the explosion and everything should be good to go now we have just a little bit of work left and plenty of time in which to do I want this to be wrong I guess there's a couple of ways we give you a list of the simple way first just for sake of ease notice here on the event begin play we choose our random color and everything let's give it delay let's say after how long before we start blowing these up two seconds three seconds with little pile up for this let's say five seconds say after a five second delay who actually kind of what was too close to a random delight Holly had letter random is a lot more fun you can take that a lot away so stake out the duration and we're actually going to feed that a random value between 0 I don't know say three seconds and five seconds that'll work and as soon as that's done we will simply call kill this guy that should be hit hopefully this works unless I've done something horrible make sure I saved everything just in case i actually do blow something out it's happened and let's see let's just simulate so they're blowing up but it might be a little forceful it's possible that that's a little extreme yeah maybe we back on the force just a little bit but hey everything's working right we got our force we got a particle effect we got our sound the particle effects actually admits it's own light so we don't under worry about that at all that makes me really happy let's take that ain't no horse component and maybe pull that down slightly to a lot of I would say happy that's right work then I believe the answer is it's amount of force applied to the actual mass of the object because we define all our sizes and centimeters matts it becomes out of grams and kilograms so it gets difference but I was never very good at actual physics you spikes punching numbers until I get the kind of explosion that I want that's the artist approach right and that's where it all looked like the the cs degrees are kind of like don't worry they'll come behind me and clean everything up right that's a big room ok so let's see let's just test this end I want a slightly saw your explosion oh god okay so it's still got what I'm down to the wire in terms of time but I want to do something a little bit fancy so what we're going to do is I'm going to build a self-destruct button so we love the cows up when we feel like here's the way we're going to do this as each cows is created notice we have a return value we see that cow right so let's take that and let's promote it to a variable which we will call cows will keep this super simple I'm going to disconnect and I'm just going to remove it from the graph real quick I just want to exist so i can turn that into an array go ahead and compile make sure there's no errors so I now have an array of all of the cows so let's get that or each cattle that is built I want to add an element to this array so there's a note for that now we're doing some program except for working for the Rays what are we going to add whatever came out of the actual spawn each time we build something we're storing it into this around very straightforward okay now what are we going to do well let's say that's quite an input and there's a few different ways to do this i'm going to show you the right way though this is going to be so fast that you're taking notes you'll get it i'm going to go to my project settings and under inputs i have some action mappings let's go ahead and add one we will call this action mapping cow self-destruct and we will expand it and we will slay this to let's say to eat but easy done will say that as a default great close this out okay now here inside of our cow slaughter we're going to do something a little bit not something I would recommend usually I have a lot more elegant with how I handle inputs would forsake of speed we have Auto receive input we're gonna set that's a player zero that mean this guy's always listening out for inputs from players rhythm now that we have that in place we can just right-click you're in the graph and let's see we have Selva Cal self-destructs I have an event for it now so whatever I hit me this event is going to fighter and what we want to do well we have actually I'm sorry I'm putting this in the explosion with something doesn't explode in this you know that we don't need that anymore let's go over to cow slaughter thank you you know what I did to tonight but we don't want him to listen to it but that's good cows boner we do awesome just make sure I'm in the right object right time so self-destruct for the cows boom what are we going to do we're going to run a loop for each loop using this array alright or each Oh fantastic so soon as we press this we're going to fire out the for each loop using our array of house and what do we want to actually have happen well for each one of those for each element that comes out which essentially is each cow we want to call the kill discal function and notice the system is aware of that since this is actually using the cow class as a data type it knows the killed miss kau function exists there so we can call that and unless I'm terribly mistaken this should already work we just need to make sure we take our house and kill that part of it that makes them blow up on their own so I'm just going to disconnect that by all clicking on the wire and they can't go away so it is all worked and I can do anything too horrible we should be able to play game but the cow is build up for a while shoot about one week of reward and then it and they'll blow now last thing because we're literally are down to the wire but it's going to make this so much more satisfying let's take out the dynamic cow and when we kill that let's do this let's do a delay soon as we kill it you got any more do it really i thought had to be done it 1215 okay you we'll make it work so go delay and then let's do a random range ratan um you know I can't spell and let's say as soon as we kill this you're going to our soon as we fire this event you're going to wait for anywhere from point two seconds to about 1.5 seconds and then you're actually going to blow up cap so let's close all of this out actually I'm going to do a file save also don't lose anything that's happened for two and it's always depressing let's take our volume will make it a little bigger let's hit play oh my god get out of the way all right okay sorry all right let's hit e so it's only blowing up the ones that existed at the time there we go if you see how that delay changes things so you guys got what you asked for we went a week we had between useful and fun of bizarre I hope this was fun & bizarre enough for you do you guys want QA or do you want me to try to thanks or do you want me to try to show you some useful stuff to use your useful stuff okay we can do useful stuff so what I want to talk about I guess for a useful segment which I've all kind of sort of done through fairly quickly is making things interactable in your name which can mean a lot of different things right when you're playing a game you want to be able to walk up to a lot we're using the you kids are the EQ boil up calots i'll probably change that in a minute because usually when he hit the e key to game let's gonna do a variety of things right in some cases it might pick up an object in other case is going to open a door and some cases going to turn off the light I want to show how to set up that type of relationship quickly and simply using this first-person template but first we need some things that we can actually work with some things we can turn on and off so let's see we've got this ceiling light that already exists here we've also got this little wall sconce let's grab the balls bouncing this might be a kind of an easier way to work with this this is a blueprint that already exists as a part of the starter content so I'm going to grab it drag it on the wall will frame up on it and let's hit geez that we kind of see it a little better it needs to be aligned to the wall surface I'm going to rotate it a little bit go and you can see it's shining a little bit of light on well we could take the whole thing and scale it a little bit that might kind of help make it a little more visible oh also when I hit play let make sure that playing to the location of the camera not from the players start that way we don't accidentally jump around our location they don't really want again so what I'd like to have happen here is to be able to walk up to this light and just turn it on and off using the e key right now when i hit a all the cowboy up so let's fix that first i'm going over to my project settings once again you remember on my inputs we took those action mappings and we had a cow self-destruct currently slated to eat let's change that over to our push that one key over and then we're going to add a new action mapping which i will call use what's been that let's actually set this one to the e key and so a little more conventional something you might have actually seen in one two or five thousand different names you might have played now here's the deal of our cows bonner we set up earlier we did we told it it should always be listening out from inputs from the player but general that's not how you want to handle things you want to be a lot more i guess elegant when how you handle inputs of how you pass them off between different players so let's start there let's set up our little wall sconce here so that it can dynamically handoff control to the player and take it away and a common way to handle that is by of proximity only when the player is close to something should they be able to actually use it when they step away from it they should be able to use it anymore that's pretty easy to set up in blueprint it's affecting a lot of ways it's very similar to how you used to do things in kismet and you've ever played with that you had things like trigger volumes of what now we're going to do something really similar let's go over to our components list and here we can see the wall sconce we use of a light component that makes it up to this list of components we're going to add a box component now we're going to resize this a little bit we can move it around freely we can scale it we have all the same types of controls that we have in the viewport I'll make us a little bit wider it's going to be super wide and pull that in just a little and will kick up its thickness and then I'm going to try to make it kind of flush with the back of the light fixture it does not have to be perfect this is necessarily need to be an exact science but if you get a lot of these overlapping you could run into problems you want to keep this fairly trim down to just the object you want to interact with let's call this essentially give us a name so we'll rename it trigger perfect now back over here in our crap we're not going to worry about the construction script in this case just to show off what the construction script is doing is allowing us to send some public variables for our lights you see over here i have the brightness that i can adjust and get real time feedback and take the light color and make that really anything we want and that's because each time I make a property change the construction script is firing now in terms of gameplay the construction script will only fire the moment this is spawned when you play and it will never fire again so it's a way for you to have some in editor behavior as well as using the event graph or your in-game name so in terms of that let's take our trigger which i just added a moment ago I'll drag that in excess it's not dragon I'm sorry we're just going to select it over here in the mind blueprint list right click it at the very top you see we can add events for it and one of these events is called on component begin overlap which is a little bit of a mouthful but what that means is when we have entered the space of this volume when it is overlapping with us we want to do something on that note that reminds me over an hour components what make sure that trigger has some specific collision properties an easy way to do that is just change its preset will tell it to behave like a trigger let's just that happens to be one of the names of presets if you want to know what that does if you're the kind of person says I hate presets because I never know what's going on in the hood all it's doing is changing a series of checkboxes about how you're going to collide with objects are you going to block stuff are you going to register overlaps with stuff what types of objects do you want to collide with an optical eyelid and so on we're going to use the trigger preset for the sake of speed and then on our component begin overlap we want something that happen what we're going to do is we're going to enable input you