Creating Growth Effects with The Pyro Source Spread || Houdini Tutorial

hello everybody my name is kate today we are going to be talking about one very cool node called the simulate spread or pyros or spread stop this stop is very interesting because it allows you to create gross over surfaces and these surfaces can be applied to characters as well as objects so we're going to discover how we can use this and stop in many other different ways besides just spreading fire we're going to be talking about how you can create these gross over this character today so almost like a sci-fi growth and take it from there so let's get started as you can see here i've created a few different growth simulations the first being this kind of almost organic growth that kind of looks like coral or the bottom of the ocean and the second one i have simulated a similar one but without the bumps so we can kind of layer them over each other as you can see here where they have some very interesting different qualities and when we play them together you can kind of see that they grow at different rates and they also create more interesting mesh across the character the other cool thing we're going to cover when it comes to growth effects off of on characters as well as to talk about how you can create kind of wavy particles across the character's body as well so um that's something interesting this node can also help you create and in this process of talking about the particles on this character we will be also going over the race op itself so let's dive right into the to creating these three different types of gross starting with the [Music] simulate spread or pyrosource spread sop this sop is relatively new to houdini and it was introduced a few different versions of go um and as you can see here i'm generating a growth system with it and the grow system can be set up in many different ways but we're going to start with the basic elements up here so starting with a grid um you can see that i've given it 50 rows and 50 columns and i made it around the size 10 10. then i've added a pyro source what this pyrosource is doing is creating a surface scatter um creating some particle separation and scale as well as a name called temperature and you can see here that the temperature is set as zero the reason it's set at zero is because we don't want any of these surrounding kind of black points to have any value when it comes to temperature quite yet we want the starting position to be the only position that contains the temperature so as you can see there's a little box here called hot region it is at the corner of my grid and then you can see that there's a group down here called great hot and it is in only contained within this box then you can go down here to your attribute wrangle where it will set a temperature of one to the anything in that so now back to our special node called the pyrosource spread um you can see that we have very different ways to visualize things with this tool so using the different visualizers we can see that we have temperature burn fuel and diffusion across the surface since we are only really focusing on temperature that that is the type we care about and we will also be taking a look at total burn as well so we can also play with the diffusion and the max neighbors that we need in our simulation just to change how the simulation spreads over time as well as how the attributes spread out so um depending on the cooling rate it will end up cooling off slower or if you so if we lower this down to one and let's say we play it back you'll see different changes happen in the simulation so let's let that kind of cook out for a bit and you can also see the around the edges it's a lot less intense as well so we're gonna change that back to four and we're gonna go take a look at our different things that we've done down here now down here i've deleted everything deleted everything that's not under the attribute total burn and it's little range down here and i'm deleting by points and delete non-selected from there i am dropping down a vdb from polygons um to have a voxel size of 0.003 and a point radius of 0.6 i'm smoothing it out and converting it to polygons and then you down here you can see that together it's kind of created this little traveling mesh across the grit so that's pretty much how it works and how you can start to visualize different growths besides creating an emitter for pyro objects so over here we're kind of using the same concepts however we are using tommy and we've taken away tommy's textures but we're keeping the clothing and we're using a high-res uh geometry then we are adding an attribute noise to create kind of a pattern over tommy and we are scattering points into that uh for my settings for my attribute noise i've gone down here within minimum operation and an amplitude of 1.94 played around with the element size and offsets and with the other fractal offsets down here then for my scatter we've played around with the force count total but that's pretty much it and then i've cashed it out so we have this points across the figure the next thing i've done is isolated some of those points with a delete so we have an entity of points operation delete none selected and selected between one and three hundred then we've used another delete to really narrow down even more points so now we have a range between 1 to 30 and the same settings up here then on those points i've copied some spheres so we can have different starting positions of the growth and if we go back over here to our output with our go back go back to our cache what i've done down here is also added a pyrosource so this is now officially a pyrosource with that temperature attribute and we have our group selection down here called hot and now you can see all over the character different starting position and down here once again we have our attribute wrangle going over that group and a temperature of one and now we are down to our pyrosource spread now i'm going to let this cook out for a bit and then we'll talk about it so now that this growth is all cooked out we are visualizing pretty much none uh so we can see the full intensity of this growth over the character and as you can also see the cooling rates we've lowered it to 1 rate of what 0.1 search radius of 0.2 max number is 23 so now it's really progressing over the character the more you increase the max neighbors the you know the more neighbors will be picked up in the simulation and the further out the growth will grow so if we change this number to say let's say 45 and we start the simulation we should see that the growth travels more over the character and as you can see it increasing the max neighbors has made the growth connect more over the character so now jumping down here let's get into the last frame so we can get a really good visualization of this go down to our delete and we delete anything under that value on the total burn the next thing we want to do is add dvd from particles and change and customize our boxes size and point radius scale so as you can see it's really quite progressing over our character then we add a vb smooth to smooth it out to make it a little bit more clumpy and convert that to polygons and then we cash it out so zooming in we can see we have our mesh um i'm keeping my my old cache because i don't want to recache in the middle of the tutorial and then down here i've added some extra texture to this in this point bop i have played with my geometry positions so i've added some noise to it um and as you can see i've promoted the frequency offset amplitude and roughness added a fits and a displacement along the normal and then fed this back into the original position uh if you scroll down you can see i can play with my frequency and the noise in that and then i can also play with the roughness as well so i'll get all different shapes in my growth the next thing i've done is add a null so i can collect it on the surface now jumping over to our second growth it's pretty much the same concept and has the same emitter workflow but let's go over it again anyways so we're once again using tommy and then we've added our note the next attributes we have our cd and we've kind of made the holes on the character a little bit smaller and played around with the max octaves the element size minimum maximum and also the post processing then we've deleted the geometry uh that we don't need for this character and we have added a scatter for me just adding the delete and deleting the geometry before the scatter was easier um and replaced uh the points where i preferred them to be so that's kind of just why it's there um it isn't necessary in the simulation then i've cached everything out add another pyrosource and created those temperature attributes then on this side once again deleted my selective points with 1 to 300 range and a 1 to 31 range then i have my copy to points with my sphere and scaling the sphere will also give you a bigger surface area to emit from when you have your when you're creating your group down here then we once again have our attribute wrangles setting the temperature and now we can go back down to our pyrosource spread so letting that play itself back we will once again go over this simulation so once again we have our growth climbing a little bit differently over our character um because we've once again played around with the settings on our power spread we've kind of given it more fuel and a post burnt rates and gone over to the combustion side and gave in another recognition temperature and played around with the max search neighbors and rates as well as cooling rates and nothing much down here then once again we've deleted what we don't need so at total burn and this time we've added a connect adjacent pieces so the connect adjacent pieces is basically taking the points that are coming in and creating kind of a kind of like a swiss cheese effect across our character i've played with the search radius and the max search points and then i've smoothed this out to make it more spider webby then we have a bdb from particles played around the voxel size vdd smooth and we won't see the spiderweb effect start to take place then we've converted this to polygons and cached it out and this is kind of the final result for that mesh then we've added a null so we can grab it off the surface now finally over to the particles the particles are a little bit more complicated than the other growth effects that we've developed now starting with tommy once again we are just going to remove all his textures and we have an out no then we have an attribute noise which we are playing with to create these different parameters and then we are deleting parts of it that we don't need scattering our points by our color distribution and caching everything out then we've added a null as well as a pyrosource to create our temperature attribute next over here we have our deletes because we're deleting our range of points between 1 to 300 and then one from 1 to 31 then we have our copy to points our spheres and our group creates where we're creating our hot group then we make the region hot again with our at temperature attribute and then finally we go over to our simulate pyrospring so we'll let that cook out and then we'll come back so yeah once again our pyrosource spread is working which is fine we've played with the noise type this time kind of remapped it just a little bit the next thing we've done is play with the max neighbors and the search radius from the rate as well as the cooling rates for the fuel we've kept it at two combustion pretty much the same down here is where i'd like to re-time things so i wanted this to travel more over the character than what it currently is doing so we're going to let that cook out again i'll just a little bit more and then go over how far it's progressing over the character so as you can see the growth has progressed a little bit more over the character which is great and i've remapped it between the given an input frame range of between 1 to 600 and a speed of four then i'm deleting everything beyond that growth so a total burn i was under that number and this is where i'm adding my pop net this is where it gets a little bit tricky so diving into the pop net you can see there's one of two things that's happening here one we are bringing in our points so we are having a mission type of points and we are using the geometry source to use first current context geometry and then we are having an impulsive activation of these frames no um it is basically emitting around these frames we've given it a constant birth rate of 90 000 and haven't changed anything about the life expectancy we've also added a pop win to give it some swirl size and amplitude and i haven't really retouched the pop silver or pop object in any way but over here you can see we have a static object for growth or collision objects so we can display it and we are displaying tommy haven't changed anything about his physical conditions or his collisions minus his division size so if we look up here at our collision objects you can see it's attached into tommy at the top so we have our collision source where we've lowered the voxel scale to 0.009 we have our empty file cache and tommy should look somewhat like this so down inside i'm going to be turning off tommy for this playback so playing back the first 80-ish frames here you can see that the particle simulation is doing its job it's emitting particles through the frame range that ranges that we specify however as you can see it's not really sticking to the character and this is because we need to make it do so so inside our pop net i've added deletes it's delete the character collision object so it does look very impressive with these kind of trails coming off tommy but you can also uh make them stick to the character so by delezing away the collision objects you can ray the particles back on tommy i've taken in the character up from up here where we have our null called outchar2 so he's bringing in tommy from there and then i'm going jumping down on my ray and giving it changing this method to minimum distance and this minimum distance will make your particles basically stick to your character you also have the option of projecting projecting them away from the character as well so they can look kind of almost abstract and weird then down here i've added a null and then i've cached everything out so for playback reasons if we play this back we kind of have a ghost tommy which is really cool and that's pretty much all it for these different kind of gross solver methods so i hope you enjoyed this tutorial my name is kate and i'll see you in the next video bye

Channel: Kate

Views: 17,062

Keywords: animation, animate, animationschool, demos, student, VFX, visual, effects, sims, simulation, Houdini, tutorials, nuke, davinci, resolve, sidefx, nebulas, water, comp, compositing, space, particles, trail, pop, net, volumes, VDBs, smoke, pyro, portals, abstract

Id: RTazkg96b10

Length: 17min 40sec (1060 seconds)

Published: Thu Jan 13 2022