How to Make a Particle Explosion Part 1/2 - Houdini Particles

Hey, guys. This is Eric. I'm back with another Houdini tutorial and this time I’m going to introduce you to little bit of particles and dynamics to get you started in that regard. So let us get do it.

First thing, I’m going to do is at this sphere. And this is our sphere right into the center of my grid. Now, what I want to do with is I want to go to my second menu input here and go over to rigid bodies, and I’m looking for this illogic here called rigid body object.

What I am going to do is I am going to select that and a little bar will come up and it is going to ask me to select what body I want to turn into a rigid body object so I select my sphere and hit enter. And that turns it into a rigid body and you can tell that because when you push play it falls off the screen and if it falls off the screen really fast, you need to turn on your real time, right here.

This little button right here is your real time and once it catches if you want, it will play it right in real time about 25 ranges a second. Now we have our rigid body attached, you can see this two up on auto bottom at work, not down here so I am going to do is I want to select that new node and I am going to add rigid body pin. I want to see this right here. I will hit enter and I am going to select it. Now it wants me to select the object and the rigid body object I want to pin and I am going to select my sphere and hit return.

Now, this little cross-here will come up and now I want two references to sinner. I do not want to put a way over here or way over here so I am just going to hit return again, and that will put this little cross here into the middle of my globe and I am going to take it and I am going to bring it up. You notice that when I do that, it does not affect my sphere. I am just affecting the point that I pinned. Now, I’m going back over here to my view here. I’m going to hit the LP to lay this out and now you can see what we have here on our node view.

We have our two margins, we have our sphere, we have our solver, we have our gravity which is not going to fall on and we have our constraint note so here are the objects but did not go back to the objects level. I want to select my sphere, down move my sphere over a little bit like this. Now when I play it, you can see we put this little P in here and it is swinging back and forth on the pendulum so let us just stop this. Go back to the beginning. Now I am going to go back up to rigid bodies and I am going to create a ground plane.

Now before we even create ground plane, let us create some particles, so let us go to our create particles bottom and there is a source front right here. This is going to tell us, this is what I want the particle source to be. So I am going to select this and it is going to tell me to select the geometry that I want to use as the source of the geometry but I think it is already got that selected for me and it does.

So now you can see we are admitting some particles from our little pendulum here that we’ve created. Now if it doesn’t automatically do it for you like I wasn’t expecting to do. I was expecting to have manually selected this sphere and hit return but obviously it is smart enough to know where you want to attach the particles to.

So now let us zoom around here and push play. You can see we have this little dynamic scene here. Some particles admittance, go back up to object level. So now we do not want our particles just flying out like that, unless we want go in straight down so let us go work to our drive particles menu and hit gravity. Now it is going to ask me to select the particles that I want the gravity to effect so I am going here and click the particles like that, and hit return.

And as you can see that applied gravity, and now they are shooting out from the bottom. Okay let us go back up to object level here, go back to the beginning. Now let us add the ground plane so go to the rigid bodies, ground plane and I will show any ground plane. So let us move our ground plane down. Let us play it back here. And move all around and play that a little bit more.

Now we have this little scene here, this little pendulum swinging back and forth but you notice the particles are going through our ground plane and we do not want that. So we are going to have to, I call it the behavior because I’m used to working with motion so we need to add a collision to these particles. So I am going to drive particles menu and I will select collision. Now it is going to ask me to select the particles first, so I will select the particles, hit return. Now it is going to ask me what I want to collide with and I am going to select the ground plane, and hit return.

Now when I push play, those particles are bouncing off that. We do not want to do that, we need it to maybe slide off so move over here to behavior, under behavior I want to select slide on collision. And now when I push play, our particles come out and they slide off, they see they go of the edges here, not bad, huh?

Now that these little particles are done with it, so let us make it a little more complicated. Let us stop things and let us add another sphere, I will control-click on sphere and I will bring it up here above my original pin spot like that.

I want to change it to polygon. I will change the frequency to one, just to make a little less complicated. Now I’m going to add a box by control clicking on box and I’m going to leave it right where it is. So now I’m going to select my sphere again and I’m going to go back up to rigid bodies, and I want to select the rigid body points. Hit enter or hit it and select it. It’s just going to ask you for what objects you want to instance, select the box you just added and hit return.

We will place it over here and let it catch once. Now as you can see, we have these boxes that were instants from four, and when I play it. You can see everything interferes and is dynamically interacting with one another.

So it will catch you through once. And you can go on and on with this. As you can see you can go back to object level here, zoom out. We do not particularly need all two hundred and forty frames in this. So let us make these hundred frames and we will click on the little bottom right here. We’re going to parameter in 100 inner and apply unless if you want to change things say yes and close.

Now we have little hundred frame animation here, and if you ask me, this is a pretty good little introduction to dynamic and particles with Houdini. I hope you guys have got a good idea of what is going on. Now you can go on and on with this. You can add gravity to these boxes if you wanted to fall off the edge of the plane here, the ground plane. You can have over fall off as they roll off. There is so much stuff you can do from up here but I hope this gives you an idea of how to get started with particles and stuff. And do not worry we are going to work our way into liquid, into fire and smoke, cloth, wires, fur and we try to cover all this and give you a real world example like what I have done here. It is in simplified terms and maybe you all can follow along.

So this was covered on the Houdini website but it was just kind of hard to follow. Maybe I’ve put it into simpler terms for you guys. So, if you have any questions, get a hold of me and I’ll answer them if I can. So I hope you learned something and we’ll see you next time.