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Gravity Based Particle System

Time to create falling rain! Learn about the 3D Region and Velocity nodes included in the Basic Gravity-based particle system, and the way Jean-Loïc has set them up .

About the Author

Jean-Loic Fontaine

Jean-Loic Fontaine

Concept Artist

Burrito Studio


Jean-Loic Fontaine

Video Transcript

Hi, Jean-Loic Fontaine again, showing you how to use the particle system in Toon Boom Harmony 12. In the last videos, I covered how to create the rain droplet on the surface of the water using a basic particle system and now I am going to cover how to do the falling rain on top here using gravity-based particle system.

So here I have the default gravity-based particle system that I renamed RainFar. If we go into it, you see that by default, gravity-based particle system comes with more nodes than the basic particle system, which is a sink node, Gravity Node, and Velocity Node, a node that I will come back later on.

For right now, we are just covering the change I did to the Sprite Emitter compared to the basic sprite system with the other drop. If we enable the Sprite Emitter here, we see that in my 3D Region, note that I use a 3D Region for the rain instead of a Planar Region, that way I have a box with more depth in it to create more variance in the Sprite Emitter. So notice that here in my 3D Region, I add all my particle generated. I use Rendering Strategy, Use Particle Type, because if we go into the drawing, we can see that I just have to create a small drawing, a small stroke of rain. Using particle type tells the particle I'm going to use a certain type of drawing. If I go into Generation tab, I can set here by saying sequentially assign type number to use either the frame 1 or frame 2 or frame 3 in order to create a bit more variety in the rain drop. I set 200 rain drops per frame since it's far away and we need a lot of it. Eighty percent saturation, that is the same thing as in the particle over the sea. And size over age, 0.2. This is pretty much it as in term of the Sprite Accelerator Emitter.

If we jump to the node that is most interesting, let's jump into the Velocity Node, which is a new node that we haven't seen yet. Velocity Node, if you see, I just enabled, pressing "A," what it does is that it sets an initial speed to each particle that is generated. Right now, trigger is on, and I say to go Random in All Directions 2D. There is other variable that you can choose. I tend to prefer using All Direction 2D, I feel gives a very good result especially because you can control in which axis the velocity will spread out in the beginning. I choose all axis to the particle will evenly spread.

And you can set your speed. So here I have the speed, a minimal speed and a maximum speed. It's similar to note that by default, I found that the speed of the particle in Harmony in gravity-based is quite fast, so I always tend to reduce the speed by a factor of 10 even before starting working. So that's why I think it's, by default, around 0.5 and I could add 0.05. And this will allow the particle to have a bit more variety in it because they all have different speed when the gravity is applied. So we'll cover the gravity in the next video.