Create Looping Realtime FX Using Houdini | Free Webinar Replay

all right guys well thank you so much for joining us for our third ever live webinar here at rubble way i'm caleb i'll be moderating today's webinar but i certainly will not be teaching anything in unreal um that will be left to urban prodesco who is our host uh he has an incredible presentation to show you guys but before we get going we wanted to show you something that we are just super excited about so last week we launched our rebelway student reel for 2021 and the homework's insane i mean it rivals that of hollywood blockbusters so i'm gonna play it and we're all gonna geek out over this just for a second [Music] [Laughter] dude yeah especially that last shot with the you know it looks like uh it was shot on the phone it's so good best one it's so good man yeah it's so funny how those projects compared to like the homework that i had in film school it's not even on the same planet like revelation students are absolutely incredible yeah i mean i think each year we get way better you know in i mean we get better when teaching we are getting more and more students and the homeworks get better and better and i wouldn't even call them homeworks it's just you know it's projects that people do after they get some knowledge from us and you know sometimes they know they have a really rich background already in the effects sometimes they're a complete beginner and we yeah we try to help and everybody uh to achieve whatever they you know their goals essentially yeah yeah and that's a good point that i think we're beginning to talk to a lot at rebelways the fact that you know our instructions and our uh courses up to this point i think most people are like oh it's like the advanced highest level like ilm quality and that's absolutely true but we're really introducing a lot of beginner content to help people bridge the gap so that they can get there even if they don't have a strong foundation in vfx it's really cool to see that we now have a pipeline from someone coming to us and they're like hey i want to learn vfx for the first time and now they can take houdini fundamentals an intro to effects and then they can branch out from there and learn what they want to learn it's super cool and i think it says a lot about um just the work that you and sabre have done over the years and just our entire team of instructors it's really exciting yeah i agree 100 so i think that's all the housekeeping things that we need to address here um i just want to introduce our host real quick so he is an incredible real-time effects artist who has worked at triple-a game studios he's worked on cinematics for projects including destiny 2 heroes of war five days gone love death and robots you might have heard of a few of those he is also the vice president and creative director here at rebelway and the instructor of real-time effects for games and cinematics so ladies and gentlemen let's put our hands together for our host for this morning or evening depending on where you're at mr urban bradesco yay i'm just imagining an applause anyway yeah dude thanks for the introduction i don't think anybody introduced me that way in that way before it's kind of weird [Laughter] uh anyway should i just start uh and start sharing my screen and just yeah let's just do it does that work looks good all right so what are we gonna do today essentially i'm gonna show you guys so this is essentially the first real-time webinar that we have and we i i think we're gonna do multiple versions of it so this is part one uh we're like we're gonna probably do part two and part three for the pyro stuff as well but for part one i just wanted to go through some of the i wouldn't say basic but the things that at least for me work in on those projects i usually have to do a lot of the looping stuff like looping smoke stacks looping explosions and anything in between because that's actually very valuable and i'm gonna show you a bunch of breakdowns uh from battlefront 2 because i think they have some of the best explosions in kind of real time like almost photorealistic explosions in a game so we're going to go through all of that i'm just gonna talk about a bit of the theory a bit of the art direction and then we're gonna go into houdini and i'm gonna show you guys how to essentially show you guys how to loop some stuff uh on different expl like on our spokes stack and we're going to loop an explosion like this so that is just hide this and we're also going to jump into unreal where i'm i'm gonna show you how then you can use that looping smoke stack uh and then and you know actually use it in a game so let me just go back to premiere uh so yeah the title if we had a title it would be sure but can you even loop and essentially this is what we're going to be taking a look at uh how to do something like this in unreal and all of them like i have a bunch of different smoke stacks here and they're all it's the same asset but in some cases you wouldn't even know because i scaled it up and down i changed the offset the timing and the lighting also helps because you know the background is blue and then the smokestack is orange and i think it works quite well for just being one asset so we're gonna take a look in unreal how this is set up later uh this is the render of that smoke stack and you can see it's looping and smoke stacks like this are actually quite difficult to loop because they have and you can see in some cases it's not a completely perfect loop especially in this rendered version because you have such low density so low value values of density and that is very difficult to loop you can see here some of that density is kind of being eroded away just so it looks a bit better but this is the rendered version and this is looping as well and i saw this loopable explosion thing from uh battlefront and there's a whole thread on this i can quickly show you guys here uh from simon uh he did a whole breakdown of a lot of different ex effects in uh in battlefront and i think i usually you guys should check this out the thread it's very cool but i'm gonna show some of the examples from it so this is one of the loopable smoke explosions they have and it it's actually quite interesting because the explosion is still going upwards but it's you know static in the middle and they use it here you can see it being used here quite well uh so if you look at on the left you can see there's actually three of them so if i can quickly do my drawing thing here there's actually three of these looping things and they just continue going up and the reason why you want them to loop like that is because you can erode them at any time you want so you have full flexibility on how long the explosion is gonna last because of it so that's the one they used here and i tried to recreate it and this is what i got so it's you know i think it's very close to what they had and this is just another version and again it's it's literally an explosion but it's just looping in place and then you can do whatever you want with it in this case you can do stuff like this so i'm gonna show you guys how to do explosions like this because i think they're pretty cool so we saw this one and the next one is kind of a breakdown of all the elements that they're using so you can see they have fire you have ground smoke sparks debris some more debris chunks of metal that are actually colliding with the ground more sparks and then all the different layers that make that effect awesome and at the end they have that smoke and you can see you can see them again the three spherical explosions that are happening here another really cool smoke stack uh in this case so they have like this is really good like the way they have it set up here is amazing with the light and everything and with the ray marching it's it's top of the line for sure uh here's another example with the lighting in place and they're probably using that six point lighting the setup that let me just quickly showcase something maybe i have it here so the six point lighting thing is it looks like this and we show i show how to do it in the actual workshop uh on the rebelway's website i'm not i cannot show any everything here because that would take us a couple of days but uh this is essentially it and they're using it quite well as well here in this case and you can see they have multiple planes so it's not just one simulation it's actually multiple loopable smoke spheres and they have they have actually a lot of planes here um i i would wonder how that actually affected their performance and if they actually used so many planes uh and not sphere sorry uh yeah like grids for this uh but yeah it looks amazing so that's what i use and this is the six point lighting setup again you can see the what they use for the smoke trails uh which is quite interesting and this is all the the grids that they were using for that explosion uh for this one which is quite a lot but it i mean it does look amazing but that's a lot of a lot of freaking grits and that's another smoke stack yeah for some reason this video doesn't want to play that well but yes it looks pretty good it looks very similar to what we're going to be doing today this one i think they still had multiple grids here but i'm going to show you guys how to do it with just one simulation in houdini and how to loop it and again here they have for the ground like for the blasts on the ground they have loopable loopable me mini explosions yeah so that looks pretty cool um some more examples from it from star wars you can see here front and center that explosion and it's looping again and then they just dissolve it and erode it out so that's the whole beauty of having it loopable you can do whatever you want with it so that's why most of the game assets in in games i mean most of the game the athletes in games are usually loopable especially when it comes to uh smoke stacks and explosions and you can see there's a bunch of smoke stacks here i'm just gonna play this a lot of explosions a lot of smoke stacks probably a few people had to do just this for the entire game because you can see if i stop here you have smoke stacks smoke stack in the distance explosions there's a smoke stack here one here just a lot of them look here so these smoke stacks if you if you pause here and you look at this uh it looks very similar to what we're going to doing what we're going to be doing so let me let me just let me just open this up so it can run in the background and again more smoke here you have smoke again but yeah the the effects are just going to give you more life to your scene and it's just going to make things feel more alive and you know like it's actually uh uh alive and a breeding world cool so that's the uh the the first part where i just you know kind of geek out on the very cool uh simulations that they have in battlefront uh caleb should we play the trailer again for the real-time effects i kind of have it lined up here but i think if you showcase yeah if you if you played with the sound and everything it might be a bit better [Music] so [Music] [Applause] [Music] [Applause] [Music] so [Music] [Applause] [Music] [Applause] foreign [Applause] [Music] [Music] i i've seen that trailer a million times anyway let me start screen sharing again uh anyway so i have this opened up so this is the project we're going to be taking a look i mean to be honest guys there isn't that much to take a look here i just got a bunch of assets from uh from mega scans and you know they look good we have some amazing golf race here happening uh but this is the smoke stack here in action and you can see i literally just duplicated a bunch of them and scatter them and these guys they don't even have motion vectors it's a bit of an overkill in terms of texture size because it's a 4k and like i said i for in this case i didn't care too much about performance uh this it's mostly for showcase interest purposes and you can see we still have that nice density happening here uh it's a 4x4 4k by 4k texture and it has 128 frames now you could optimize this a lot and probably somebody's going to yell at me for doing it this way you can have you can uh essentially if you have motion vectors you can even export 64 frames in some cases 32 frames and that might be enough and then with motion vectors you can slow it down to get the additional time that you need in this case for this presentation purposes i didn't do it but it still looks pretty good and it is slowed down quite a lot if i look at wha what the material looks like i was actually slowing it down quite a bit and it's just doing the basic frame blending uh you know but it looks it looks okay i guess we could try to slow down even more uh but you start then you start seeing the the stepping which you wouldn't be having uh if you you know just had motion vectors uh but yeah this is how the material looks like just a simple subuv function and then i was also powering just a bit to get rid of some of the lower densities here because they were giving me uh i can show you it still looks okay but you get this edge which is you know just additional uh alpha happening and you can fix this in some other ways that i show in the workshop uh but the easiest way is to just power it and it's gonna go away there you go beautiful beautiful uh but yeah that's how this project looks like in terms of uh working in unreal if i go well uh you know what i'm just gonna quickly show you how and all the stuff that i show in the you know in the workshop and you can see uh essentially i show how to do a bigger smoke stack how to do motion vectors how to render out different lights um for different passes because we actually do that six the six dimensional lighting setup uh i also show you can see the motion vectors here being done in houdini which is not the easiest by the way you you have there are other ways of doing motion vectors you can do it in houdini like you see here uh you have other softwares that you can do that with as well uh here you can see i'm actually yeah so here we actually built the the setup to use the motion vectors and i don't know where i did essentially we i pack so here you can see i pack a bunch of frames into the red channel so 64 frames into the red and then 64 into the green channel and then you have all in the blue channel you have the alpha for the red channel and then in the alpha channel you have the alpha for the green channel uh and that that is a way of stitching multiple frames in different channels which is just some sort of wizardry uh yeah some more stuff from the workshop i don't want to bore you guys with this but here you can see how we can then use those different light passes in this case they're you know red green and blue but then you can multiply them and actually uh change them in unreal which is kind of cool when when you think about it because you can they're not dynamic they're not dynamic in this case you have to animate them but if they're just for a background thing and the the lighting and the sun is not changing it should be completely fine so this is the motion vector thing and then i also go through how to do the normals and everything for explosions and you know all the good stuff all the good stuff that you would need in a project uh for dimple effects anyway let's go uh let's go to houdini so we're going to be i'm going to be showing like i said a bunch of different versions of how to loop stuff and the first one is using just this simple simple smoke stack that is just going up so something that is just going up is going to be the easiest in many cases you still have a lot of low densities you still have uh you know if you wanted to make it interesting it still has to go a bit left to right not not i wouldn't say interesting but more realistic assuming that we're making something for that would fit into the star wars game which they have more realistic effects so for this i'm actually using axiom why because i wouldn't say it's real time uh so for the real time stuff i would stick to uh ambergen which i can quickly show you later ambergen has some uh sweet tools to loop stuff and their smoke actually looks very nice even the explosions are looking better and better every day i've seen some pet hey urban uh it looks like some people are saying that the uh stream is lagging a little bit everybody in the chat uh are you still seeing a lag it says that some people are just clicking reconnect and it works again yeah it's okay amber john i mean uh webinar jam for some reason keep saying it looks like urban that if people just click reconnect that it's working for them so i think we're good okay yeah yeah so i forgot to mention in the beginning if you reconnect so try reconnecting first if it still doesn't work we are gonna click the panic button and it's just gonna reset the stream it helped the last time but i guess we are having the same problems as the last time as well so yeah sorry guys yeah yeah okay should i just continue caleb yeah it looks like you're good to go now all right so yeah like i said i'm using axiom you can use uh ambergen actually let me just let me just quickly do a sidetrack here because uh i think ambergen is freaking awesome and the things that they're doing right now just to uh light smoke hey and you can see this is running in real time so it's even faster let me just i don't want no animation on the light it's running in real time it's faster than uh even than axiom and they're getting some really nice details and if i go to the looping the looping part and if i don't find it immediately loop simulation i'm gonna do a dynamic quintic so i'm i'm not exactly sure maybe somebody in the chat knows what uh quintic blend is uh i think it's just something to do with the way the curves are interpolating right but i'm not sure so let me just do this as well and you will see it's actually going to loop quite well let's give it some more frames here and i'm just going to put this to 30. so yeah you can get a looping smoke stack in real time and the looping is quite nice in some cases you will encounter the same issues like here you saw that on the left it you know the smoke just appears because uh that whole shape is a bit offsetted from the main stream and that's always a problem that you're gonna get with looping smokestacks and loopable simulations you just have to experiment a bit and find that magic magical kind of blend in between so what you can do with uh with ambergen if you preview it uh you're gonna get the six point lighting right here you get the your alpha you get the emissive if you have one uh motion vectors done on the fly and you can just export all of this and it works and it's a beautiful program uh that it's getting better and better each time so but uh this is a houdini thing so we have this done with axiom i'm not going to go through how the sim is done because i showed that in a in a tutorial that we have on our youtube page but yeah we have this sim and the easiest way to loop something is you can just use the make loop soft that is included with the game dev tools so make make loop and that actually works quite well but and in some cases that will actually work quite well you can just use that but what i do is in a lot of cases i just do the manual setup here because i have some more control you can obviously go inside of here and see how they're blending uh you can see they're using the blend shape and or the volume mix in this case and they're blending and they're using a bunch of expressions to blend and that's fine but i usually want more control so in this case i just if i go to my first frame i change the the frame i just offset it by 180 it's an arbitrary number just so i have something on the first frame so the smoke stack is fully initialized i then you have to offset it either plus or minus 64 frames if you're looping over 64 frames you know it's obviously 64. if you're doing doing 128 you would plus or minus 128. and then what i'm doing in a lot of cases you want to get rid of those minor densities because they're not going to be visible in the render and in many cases they're going to actually disappear in the game they're not going to be so if if the lens density levels are too low they're usually a bit problematic so what i do in this case is i just refit and i do a power and with this i can get rid of any smaller densities that i don't need and sure that will change the simulation just a bit the look but it's going to give us a nicer blend between the two sims so let me just so i don't confuse anybody so this is the original original sim right and then we have another one that is of being offset by 64 frames and then i change the values here a bit i also animate the exponent so when the sim progresses i'm gonna erode it in you see i'm just i'm eroding it like that and i'm animating that erosion what i have to be careful at is that the beginning here so the erosion is at the beginning is set to uh should be set to one so yeah the beginning is set to one i just have to be careful that on my on the right side i also set it to 1 when it ends because the ending of this is going to be the beginning of the left side and then if we volume mix them i'm just animating the blend you can also animate the destination premolt and source premolt that also works but usually i just do a simple blend between the two and then with the pyrobake you know i just give it some let me just reduce the density of it maybe a bit more and let me do a quick flip up so you guys can actually see that this is you know looping and it might take some time to uh to actually loop this which is fine caleb do we have any questions right now that i can answer maybe um let's see here someone said there is volume simulation in unreal now that works through material functions how usable is it or is it very limited uh any sort of real time volume metrics are still very limited and i'm not exactly sure some games are gonna use them that are coming out in the future but the the best case of use right now for like true volumetrics in unreal or any other real-time engine are uh clouds people are mostly using them for clouds if you think about clouds in red dead redemption or i think even fortnite are using volumetric clouds i'm not sure that uh but there was a cinematic that was done in real time for fortnite and they also used uh real volumetric simulations but it's still very limited and i don't think a lot of people are gonna use them yet but it's coming it's gonna come for sure look at that it's perfectly looping it's beautiful so this is something that you would do six or five different iterations of this and you would just place them all over the game you would do the motion vectors for it you would uh then rotate it scale it up or down and that's it so yeah this is easy this is easy mode so you would do something like this for uh just a smokestack that just goes up four smoke stacks that go sideways and i'm again i'm just using axiom for this uh that goes sideways these are a bit more difficult the looping techniques are mostly the same though uh oh there's another thing that i forgot to mention here when i'm refitting my values i like to check what my maximum is so my max volume so there's a function called volume max and then you essentially just give it this null so the volume and it's going to tell you what is the maximum volume volume density the maximum density value and you can also do for the for that the same thing for the volume minimum and that's how you then re-remap them here with the with this volume up uh but yeah that's just a cool side note so we have a smoke thing like this and what is difficult with these guys always and maybe somebody else has a better way of doing this i didn't find any i tried i tried a lot of things and it usually just looks even more fake but i tried pushing the volume so actually deforming the volumes downwards and deforming it to the you know deforming essentially this guy more to this guy and it always just looks even more fake so i always find that a simple blend with changing the settings here and eroding it just a bit i mean in this case i'm eroding it quite a lot but uh doing erosions like this is going to give you the best result and i got sidetracked a bit so the reason why this is difficult is because of this and because of this the easiest way to do it is if the smoke stack is consistent like this and it's fine if it if it has some variation but as as soon as you have this it's very difficult to loop so let's see how this one actually looks like at the end and this one is it's going to look fine but it's because it's been eroded quite a bit and i took all the small wispiness out of it and that's why it's going to look a bit better and you can use this for wispy smoke but for you know yeah so you know it's still it looks fine it is looping like i said this area is a bit problematic and it this is always going to be difficult what you can do is uh try offsetting it a few times to try to get the right values at the end let's see if this is a bit better yeah i think this works better than before so you can see it's just a matter of a matter of experimenting just a bit so i do this all the time and it takes me quite a lot of time to actually get the smoke stack to look perfect so on this one on the right is a bit less eroded so you can see we still have the density and i'm doing the same thing here with this one with the first volume bob so i'm first off i'm offsetting it and then with the first volume up i'm trying to normalize the density just a bit because otherwise it's too dense it's too dense here and [Music] so the density level is all over the place because of you know the volume is dissipating so this is too dense and this is the density is too low so i'm just trying to equalize it a bit and then i do the the erosion and i'm animating the power uh in this case i'm using the maximum volume to one if you put this to three it's gonna wrote it even more offsetting this one but this time i'm adding 128 frames instead of minus so you also have to experiment if you want to add or if you want to subtract 128 frames in this case because this one is 128 frames and the reason why it's that long and preferably it would be 64. but for smoke stacks like this it's very difficult to get them to loop in 64 frames so if we check this one and it's 128 uh i think it's looping quite nice and we still have the low density uh here on the left which is difficult to con like to usually that's the problematic part when it comes to loopable simulations urban we had a question come in someone was asking that in the real time effects workshop do you teach unreal engine from scratch or do you have to have some sort of prior knowledge before you take the course yeah i would say prior knowledge for sure it's not an intro class it's not an intro class and some people sometimes get stuck just a bit but i try to help them in the best way i can so meaning that i wouldn't say it's so i'm gonna say this if you have experience with any other 3d packages let's let's say you're a houdini artist for the past five or ten years you're gonna pick up unreal quite fast it's not gonna be a big problem if you don't have any experience in other packages and you're starting with unreal you're gonna you're you probably should learn a bit about real time and how to use unreal before you take the workshop because we can i think we go we go from medium to other advanced topics in the workshop so yeah uh but yeah oh yeah you guys can see that this is you know looping it's a beautiful looping smoke stack i i actually like this one it has really very nice shapes it has nice dissipation and it looks pretty decent uh so yeah that's how i would loop these more problematic ones and sometimes the answer is to just have it loop under 100 over 128 frames which is sometimes not preferable and people might scream at you again so just be cautious so that's that we have a pyro loop here i'm just using uh in this case i'm using the new pyro source and well actually let me let me show you guys how i'm doing this so i have a grid and i'm scattering points and i'm creating uh some noise and calculating the length just so i get this gradient right i don't want to get too much in this but i guess you can see you can see the whole thing how it's constructed and when i copy oh and the important thing is i bind everything to p scale because when i copy lines on top of it i get this and i use this as my emitter it's actually quite important to if you're doing realistic kind of smoke stacks to to pay attention to your emitters uh i do a trail just to get the velocities from this and uh i do the spread the volume out of it you know to just to create the emitter and i scale it down because it was just a bit too big when i was doing the experiment when i was doing the setup and now if i sim it it's gonna go backwards it's gonna move oh no so why why is that uh and it's actually a very cool method uh that a friend of mine jaden he he teaches the magic class he showed this to me and i was blown away essentially this smoke stack is going to the right but what if and this this is what moves the smoke stack what if you just make a copy of this you know you go to actions create a reference copy and you negate it you inverse the transformation it's going to stay in its place and it's going to feel like it has wind it's crazy and the reason why you would do and use this one use this technique instead of actually blowing wind is that wind can a lot in a lot of cases it can distort the uh the smoke at the end it can make it look too wispy and if you want a real like a real proper smoke stack in a lot of cases this is the way to go and you can see this is what we get and it looks quite realistic and we don't get any distortion with the with the velocities at the end you know that you usually get if you're blowing wind in that direction and it looks pretty pretty damn good i think and this one is a lot easier to loop why because if you look at this shape like i was saying before it's very triangular so it doesn't have you know the other one was like this uh this one is much more linear in that case it still has some interesting shapes like here this is still problematic but when you cache it out and you time shift it and if you just blend the volume let me just show you guys we just do four frames close this one down and just do flipbook okay so that's the problematic area that was talking about you can see it here it just pops and that is going to be impossible to fix at least with i know so this is the part where i was saying that i even tried volume deformation and trying to push this down but then it looks fake in this case what we can do is just change the change the values a bit until we don't get that part and it's going to look better let me just see if i fixed it on this side so yeah if we check out this side essentially i just offset the value it's still the same sim it's going to be quite a nice loop yeah there we go so essentially it sometimes it does come down to just offsetting the values uh here uh until you get the two two sides so i'm always looking at them at the as the left and the right side and they kind of have to match in a way uh preferably they have to almost match when they it and in that cross section where they actually loop in this case again i was eroding it in because this part if i don't do this it will still loop it's still gonna it's still gonna do its thing but you see that one there was a problematic part uh see maybe it's actually gonna work but you can see here so this part is maybe you don't see it over the stream let me zoom in but it's just kind of it pops in right and that is the problematic part that is very difficult to achieve that's why i usually just erode it in this case i wrote it quite a bit but you can just do it a bit less and then this side has to match otherwise if this side has a different volume density you will see it's not going to loop anymore it it will actually have a pop that will appear you see it's popping here uh when it loops so this side has to match in terms in terms of uh the volume density and let's see if this helps because we we got rid of some of the density that was happening here at the top yeah it's still happening a bit that's why i was eroding it even uh even more but when you see this in the game it it's usually fine and you don't need those very low density values because then they like i said they're always a bit problematic in the game as well when you put it through the game engine so let's see we have the same setup here with just a different sim and this one is a bit more chaotic and it's a lot bigger so if we run it like the same thing we offset it we eroded just a bit on both sides in this yeah so we mix it and then the pyro volume is nothing special i'm just adding some smoke at the end and let's see how this works you can see it has a nice loop as well and this is only because the shapes are kind of linear here and they're matching and that's what you have to be careful with uh to match those left and right side when you when it comes to looping and that's why it sometimes it takes a bit longer but you can see it looks quite nice especially with that technique uh where you just inverse the transformations i think that's pretty pretty cool uh this next one is essentially the one that i was using for for the unreal uh smoke stack and that's also the one that is rendered here so that's how this one looks like and you can see it's even longer and bigger than the other ones that i was showing so far and honestly there's nothing too special about this one it's just using the same looping system that i showed you guys and i believe caleb i think we can after the stream we can share the hip files because i think we can yeah we can share those uh absolutely we'll email everyone who's in this stream in about five hours with a link to watch the rebel the webinar replay and then we'll include the files in that email yeah all right yeah sounds amazing okay so then the next thing oh actually kind of the last thing that i wanted to show is this loopable explosion thing so i was very impressed by this uh the work i don't know who did this maybe if you guys know this guy uh let me know i would like to congratulate him and maybe even ask him maybe they used something different than i did but this is my result with having explosions look like that and it it maybe looks difficult but it's not that difficult that you would think it's a lot of uh just messing around with the values so i have uh explosion and it looks let me just zoom in it looks like this and it just goes up and you want it to go up as much as you can and you don't want it in this case it's actually expanding quite a lot which could again be a bit problematic for the loop so you want it to stay here but explosions are going to be expanding to each side so that's something to keep in mind the way i was trying to fix that is you have it go up faster you have a very low cooling rate you don't need expansion even though in this case i think i had it on which was a mistake so yeah you don't want expansions because that that will actually make it go wider uh but you know it worked out uh in this case so there's an explosion uh i did uh all this is not that important i just removed the velocity because i didn't need it in this case pyro volume is just to get a different shading so it looks uh a bit more a bit more bright in this case and then i time shifted it again like this so in the beginning we already have something so let's shift it and then i moved everything down just a bit and this how much you move it down it totally depends on the simulation the next part that is important in this case is the camera because the camera is actually going to be moving up so you can do this a couple ways either you animate perfectly this smoke stack going down or you move the camera up in my case i was just moving the camera up if you take a look it's gonna be the camera is gonna be perfectly following the the spoke so it's just gonna go up right by how much you animate this is kind of not scientific at least i didn't do it in a scientific way it was still an approximation i was literally eyeballing it so if you thought that's how i do it i eyeball stuff and it's an approximation it doesn't have to be necessarily 100 correct uh well it has to be at least 98 correct for it to work but uh it's obviously better if it's 100 in this case it's almost 100 correct and it's just moving completely up and you that's how you get it to stay in the middle of the frame then you time shift it and you can see when you time shift that it it starts quite below so you have to transform it up so they actually when you loop them they are on top of each other like that and then when the one finish the second one will appear out of it and here we have that same problem with the low density uh the low density appearing here on the right so you can fix that by eroding them uh like that or using the power it all again it also depends on the sim quite a lot but yeah you can you can erode it just a bit to get rid of those low density areas obviously not too much because you still need some of the core density uh in this case it was kind of working but you can see here i was eroding it just a bit as well just to get rid of some of the low density areas i do the volume mix here and then on this particular case i did another erode at the end so this is again a fit a ramp and a power and the reason i'm doing it with a ramp because i can just target you see those areas that's that's probably problematic you don't want that that is not going to loop well you want to erode those areas like that and that will make it look much better maybe even a bit more so you see you want them gone essentially and that will create a much better loop like that uh the last part to the puzzle is you you know you have this stem happening here and you need to remove it for it to look like it's actually just floating up there's a couple of ways of doing it the simple way is just a sphere you convert it into vdb you have to link the transform to your camera so this transform you copy paste it you copy the parameter you paste it here and you can see the sphere is moving with the camera 100 and then you just use a vdb combined and you can multiply it or i think i used so use a vdb combine or you use a volume x for this and that will get rid of the stem at the bottom and then at the end i moved everything up a bit like that and you can see this bottom part is gone and then when you do a pyro uh big volume i just reduced the shadow density a bit and if we do give you this we will essentially get that result that i was showing you guys but i want to show it again because i think it looks pretty cool and something like this is very useful in in doing you know game effects uh unless you're doing stylized game effects uh which is a completely different thing because for stylized stuff you usually paint uh your smoke uh puffs uh it's a 2d fx thing that you have to do and we actually show some of that in the workshop as well how to do more stylized vfx actually the first four to five weeks are more stylized and then we go into houdini and unreal and we do more realistic effects but yeah we're almost let's give it a few more frames for this to finish almost done actually i forgot another thing i'm going to show you guys real quick because yeah yeah because that that's actually quite essential uh but yeah here we go you know it's looping and something like this would be difficult to achieve even though i love ambergen i think it's amazing but doing this in amberjane i don't think it's possible right now so in this case you have to use the power of houdini and using you know the volumes the power volumes one thing you have to be careful with so like i said you move this guy up right from here to here so they match in position you actually have to go to frame 64. actually you have to go to the left first and go to the beginning so this frame has to match the last frame in order to do that you can do a snapshot here like this and you can view it in a horizontal wipe like that i'm pretty sure some of you probably didn't know you can do this uh so now you have to go to frame 64 and they have to match so this so right now i'm using that preview on the right side and on the left side we have the live view so that's how you match them in terms of position and when you do that they're actually gonna then perfectly loop and be on top of each other uh because like i said this frame so the last frame has to be the same as the first one and that's the way you do it actually it's not the same frame it has to be a progression one frame forward to make it loop perfectly like this all right so that's how you do that loop and then i did i did oh let me just remove this i did another variation of it and when you do a variation you have to change the camera moving upwards because the the simulation is going to go up at a different speed uh so you have to change a lot of things this one is a more this one is way more low res because i just needed something fast to preview and that is something quite essential when you do stuff like this is to preview at probably a lower res so you can get the looping working and then uh the system working and then you do a high res sim and then you will obviously have to adjust just a bit but everything is the same and when you loop it and you view it from this camera and we do this so we remove the bottom part in this case i was so you have your sphere you do a vdb you have to do a vdb activate when you do the noise otherwise it doesn't have enough um i i always say real estate which means it just doesn't have enough space around the volume around the vdb so you have to extend the voxels to actually so when you do the when you push your position with the volume sample and noise it's actually going to go outside the bounds then i did a bit of a smooth i've pushed it up probably the smooth is a bit too much and when you do the volume mix this is what it's going to do you see it's just going to erode that and because of this noise without the noise it's going to be a straight line with the noise it's going to break that line and it's going to feel more natural and when you let's leave this one this one should be a lot faster because it's actually quite low res that's still quite slow yeah this is when using ambergen uh is would be a lot faster actually would be in real time with ambergen but yeah it's just yeah you win some you lose some anyway and you have this and this one is this one is perfect uh obviously it is low res but as as far as looping goes for an explosion going up this is pretty perfect and i think we we got very close to this example that i was showing in the beginning uh and with this uh yeah you can do amazing very packed um and let's just take another last look at the unreal project with a nice nice little god right here and you can see how nice the volumes are actually reacting to light as well look at that it's beautiful look at the god race oh my god let's remove this and then create the sequencer and if we play this pretty cool right yeah anyway that's it that's all i have oh it's been so yeah it's it's literally one hour that's fine that was amazing yeah i'm super impressed obviously we have a lot of questions that people have about real-time workflows we're not going to be able to get to them all um but i think it'd be cool if we did maybe three to five questions here at the end so if you have a question for urban please post it now we'll start with some of the previous questions here so a lot of people were asking it's the same question we get every webinar what are your pc specs so they can know what type of machine you're working on i'm working on my phone this is not even a pc wow this is the best this is the next gen uh apple phone with uh four processors so that that's that's why it runs so fast like look look at this look how fast the video is going that's how fast this computer is i honestly stop asking questions like that it doesn't matter what your pc specs are but i do have a it's a ryzen threadripper uh some version of it and then i have 128 gigs of ram and a gtx rtx 270 so it's uh the cpu is quite beefy i have a lot of ram because i do a lot of sims my gpu is not that powerful because i don't need it yet but i think i'm going to switch to a better gpu just because i think i'm going to be doing way more real-time smoke sims with ambergen but yeah guys like i don't like any pc nowadays is so fast already so you just need a decent pc that's it we had some more questions about the usage of real-time especially looping real-time effects for non-real-time purposes so for example um you know pre-rendered stuff that's going to be vfx work are there any uses for the same techniques that you outlined today to be used on typical vfx projects yeah yeah there are especially when you have a big scene with a lot of fog and smoke you would essentially rather have that smoke just loop so you you have two ways of doing it you can either sim like 500 frames which is possible and you can do that in a pre-rendered cinematic or you would have a looping smoke fog or whatever if it's in the background it's completely fine you can still do it like that so it's still quite usable like you saw with the with the big smoke stacks like that loop so this guy so having this loop um would actually be useful in a pre-rendered cinematic especially if it's a in the background kind of scenario because uh it's essentially it's good enough and the loop is so nice in this case that you wouldn't see it uh and if you have depth of field and everything it's completely fine yeah yeah you can still use it but in most cases than not you would just render 500 frames and do unique simulations uh just to be 100 sure but we had a we were working on a cinematic where we had so much fire all around the the space that we actually we rendered the fire out and placed it on cards even though it was a pre-rendered cinematic because it was so much fire in the scene that it was very difficult to work with and we essentially did a similar workflow that you would do for games but we did it for a pre-rendered cinematic and it worked perfectly so uh there cool very cool yeah so we had some more people asking questions about unreal 5 and the course currently it was created in was it unreal 4 yeah so will the course still be relevant once unreal 5 comes out in the near future i have no idea [Laughter] uh i think yes it's going to be still relevant but i think when unreal 5 comes out we're going to update the workshop because obviously in so in in the workshop we are already using niagara but even that version of niagara that we're using in the workshop has been updated so we are currently working on uh a new overview of how niagara works for unreal uh 4.26 because it's already a bit different than what i used in the when i was recording the workshop so i would bet that when unreal 5 comes out they would change even more stuff and they would add more functionality to niagara so yes i think we're going to have to update the workshop for unreal 5 when that comes up and i think that's going to be end of next year i think something like that yeah okay very cool well we do have a few more questions um i don't know if any of them are broad enough to address specifically in the webinar with everyone but i do want everyone to know that you can email us at info rebelway.net with any specific questions that you have in urban or someone else on the team would be more than happy to answer those questions so just a few housekeeping things so you know obviously urban was showing you how to create smoke and explosions using real time a lot of people on the stream like doing explosions that are going to be pre-rendered and then used in vfx work if that's more your uh desire to learn then i would recommend checking out our explosion effects course as well uh sabre has done an incredible job with that course and we're just seeing a lot of really incredible renders to come out of there a lot of the shots from the student reel that we watched at the beginning were actually from that course as well so you know just definitely keep that in mind um whenever you are trying to decide which course is right for you and i see one question someone was asking that if the they purchase real-time effects will they get the updated content and the answer is yes if we update a course you will have access to the latest content at rebelway we always try to stay up to date with the latest trends and so we'll update our courses as we need to yeah yeah so you know i think that's all that i have urban is there anything else that you'd like to add no no i mean uh i would maybe i can just close it off i think we so we what we tackle here in this webinar is actually quite important for any vfx artist that wants to do uh you know real time for effects for real-time games uh it's something that is used quite a lot and there's more to this looping stuff there's more things that you can loop and different loopable examples but that's really the gist of it and then when it comes to explosions you can either some explosions are difficult to loop and if you have a hero explosion in the game in a lot of cases it's not going to be looped it's just going to be a just a long render and in many cases you can like i was telling you guys you can stitch uh you know 64 frames in the red channel and 64 frames in the green channel and actually stitch them in a material in the engine so then you have 128 a sim the reason why you would do something like that because the resolution is going to be higher because if you pack 128 frames in a 4k texture you know the resolution will suffer because of it if you render 64 frames in one channel 64 in the other and still have a 4k texture you will have twice the resolution so it's it would look a lot better so for hero explosions you would do stuff like that so there are caveats and per case examples and needs that you have to kind of apply when you're doing uh effects like this uh and then like i said you have then stylized effects that are completely different to what we were doing here but then each game requires you know different techniques uh but yeah also andre andreas is asking but the channels are not compressed equally yes and i don't remember i think it's the is it the blue one that has the most compression i don't remember and sometimes you can see it sometimes you can see it in the alpha so when you stitch it sometimes the gamma or something is going to change because the the compression is different between the channels uh and andreas knows this and this this is a bit beyond of the scope of the webinar but i do i do cover it in in the workshop and he he is 100 right yeah you imagine that you get yelled at for making an effect too high quality so i do i always do it i i make it look so my my theory is i make it look as good as i can uh i make it look as good as i can and the overdraw would be essentially everything when you when you look in unreal let me see where is it eight it's eight oh hey here we go oh am i standing in the camera so here you have the mac shader complexity thing and i don't know why it doesn't allow me to move here we go so you can see this is essentially the complexity the more [Music] the more grids you have stacked on top of each other that are transparent the more red is going to become you can see here it's just there's this is just one grid when you have two of them it becomes red more red and then here it almost goes to white and the more if you do this and the whole screen screen is red people are gonna yell at you because it's not gonna run it's not gonna run efficiently on on consoles for uh for instance uh when we were doing gears we were working for two different consoles uh that had different performances so let's say uh you know you have your xbox and then you have the xbox what was it x and then the the newest one xbox one so they had different performances and you have to be careful essentially your game has to run on all consoles and you have to be very careful of your performance in that case but what i do is i make it look as good as i can and then people will tell me that it's not optimized enough and then i have to strip away the layers uh until it still looks okay but then the technical team is happy so that's what i do in most cases uh do you go over flow maps for slower effects i do i i certainly show how to do it and like i said i only show how to do vector maps in houdini but you can do it with ambergen and you have this program called uh slate i think it's just slate and or you can do it in after effects with twixtor twixtor will essentially create motion vectors for you and in some cases that they are even better uh there's a very good blog post by clemen lozar let me try to find it uh clement is a buddy of mine it's funny enough like we're from the same country uh just a fun fact which is always fun to see people i'm just trying to find this so this this this thing so clement did a whole breakdown on how this works and you can see this is without motion vectors and this is with motion vectors and how you don't even need any frames for you you can have like this is probably 32 frames for the explosion and you can make it look like it's running in slow motion and it's freaking amazing so good and he he he did the motion back i think this is i just show it in a video form and you know actually show how everything works and explain the notes uh so yeah that's a fun fact there we have one last question here so someone was asking where do you go to listen to presentations or to read white papers on real-time effects work uh sorry can you i was reading the chat can you can you people are wondering basically where do you go to brush up your skills on um you know real-time effects work by watching seagraph presentations yeah technical are there any resources that you go to yeah so andrea's posted it and he did a talk as well uh because he worked on was it battlefield one andreas battlefield some of the battlefield stuff right and he did a gdc talk about that as well and andres has a ton of um educational material on real-time stuff and houdini stuff on vimeo so you can check that out as well uh yeah battlefront and battlefront 2 oh amazing so maybe andrea should be doing this webinar like what what am i even doing here actually that might be a good idea to have andreas on on the webinar next time and maybe he can share some of the experience what do you guys think should we do that yes we should i think we should anyway uh yeah gtc guys i always misspell it maybe somebody knows what i'm talking about i can post it in the chat but i will try to find it just give me a second urban did you also post the link to clement's vlog in the chat i think somebody did already okay sounds good fantastic yeah and just so you guys know our courses start on friday this friday but if you sign up you actually get instant access to the entire week one that you can go ahead and start watching so you don't actually have to wait until friday to start watching your content and just so everyone knows we will also be uploading the live stream or the replay of this live stream this afternoon and then we'll post it in hd forum on youtube on thursday we'll try to do it around 11 00 am as well okay i found it on it let me come back so this channel is also very cool uh for anything related to real time just going into the mathematical side of real time as well like how to use uvs how to calculate i i learned a lot of uh the technical stuff from that channel even though i'm more i would consider myself more of an artistic vfx artist i obviously using houdini i have to be technical to some degree but for unreal i i use that channel quite a lot as well for to yeah to just yeah thomas yeah yeah yeah yeah it's it's he he the way he teaches is great and the content he produces is amazing but yeah i think i think that's it i think that's it for for this one all right well thanks for joining us everybody again feel free to email us if you have any questions and we are super excited for the next one so hopefully we will be around uh the third week of february back with a brand new webinar awesome sounds good sounds good cool yeah thanks everybody for joining up uh and uh see you in the next one yep bye foreign

Channel: Rebelway

Views: 7,033

Rating: 4.9851303 out of 5

Keywords: Houdini Tutorial, Houdini, SideFX Houdini, Nuke, Nuke Tutorial, VFX, FX, VFX Industry, Special Effects, Visual Effects, Hollywood, Simulation, VFX Tutorial, VFX Tutorials, Unreal, Unreal Engine, Urban Bradesko, Realtime FX, Looping Realtime, Looping FX, Looping VFX, VFX Loop, Unreal Smoke, Unreal Explosions, Game FX, FX for Games, Games VFX

Id: 0NgNQlpmPlQ

Length: 77min 31sec (4651 seconds)

Published: Thu Jan 28 2021