Original subtitles

Hello everybody and welcome to a new section in this section we're going to take a look at flow objects

outflows materials and more.

In this video we will take a look at the flow object and learn exactly what these settings over on the

right do and how they changed the simulation.

So first off we have the flow type.

This is currently set to liquid.

We have fire smoke fire and then the liquid just like that.

Since you are learning about the fluid simulation we are going to stick with liquid underneath that

we have the flow behavior.

There are three different types that we can choose from in flow will constantly add fluid to your scene.

The outflow will take away fluid and geometry will just be the shape of the mesh that you have applied

the flow object to.

In this case it's just going to be a cube underneath that.

We have sampling subsets.

If your fluid is moving at very high speeds sometimes it can skip a location and there'll be a gap in

between where the fluid is.

In that case you're going to want to turn up the sample subsets.

This will sample more steps every single frame and give you a more smooth fluid the flow source is currently

set to mesh and that is the only option in the fire simulation.

You can see underneath that there is a particle system tab.

But in the fluid simulation there is only mass.

So that is the only option that you have selected.

So it's just going to emit from the mesh itself.

The option here called is plainer this checkbox will tell blender that the object that you have applied

to the flow to is a plane or something that's really thin with regular fluid simulations using a plane

does not work very well.

So you're going to want to turn up is plane are if you're using a plane for the flow object.

These surface emission value controls how far away the fluid is going to be from the object that you've

applied the flow to since it's at zero it's just going to be the exact size of this cube.

But for this example let's go ahead and bring this up to a value of one.

So when we bake in this simulation it's going to have a little bit of fluid along the outside edges

of this cube and underneath that we have initial velocity.

This is where we get into some interesting stuff.

If we turn this on we can give the fluid some initial velocity right at the start of the simulation.

We have the source right here and this deals with the movement of the flow object.

For example if we were to animate this object here let's say it starts here at Frame 1 and moves across.

What this will do is it will move the fluid with the flow object.

If we turn up the source value underneath the source we have the normal value.

And this will enable the fluid to emit along the normals.

Now if you don't know what normals are they're basically the way the faces on your mesh are pointed

and to actually see this we can turn these on in the 3D viewport if we go into edit mode and then go

over to this menu here we can enable the normals down here.

So if we turn on the faces and bring the size up these are what the normals look like.

And you can see which way they're pointing.

So if we were to turn up the normal value here it will met fluid in that direction.

I'm just going to leave it at 0 for now.

And finally underneath the normal we have the initial X and Y and Z location these values will enable

us to give the fluid some initial velocity along the axis that we choose.

So for example along the x axis what I want for this simulation is for the fluid to fly off in this

direction and hit this wall.

So I'm gonna set the initial velocity along the X to a value of 2.

So when we bake in the simulation it will shoot the fluid out along this side.

Now let's go ahead and bake in our simulation.

So I'm going to select the domain and then just click on vague data down here we can see the progress

bar and once it reaches 50 we can play our simulation.

And now if we restart and hit the spacebar we can see the initial velocity is working.

It shoots the fluid out and it hits the wall.

Let's go ahead and restart and play it just like that.

And that is pretty cool.

And another thing to note is the fluid is along the outside edges of our cube since we set up the emission

surface to a value of one.

You can see it's along this edge.

And then if we go to the side it's along this edge it's outside the borders because we set the surface

emission up.

So there we have it.

That is the flow behavior geometry and in the next video we will take a look at inflows and outflows.