Original subtitles

Hello everyone.

And in this video we are going to look at the guides in the domain settings the guides allow you to

use an object or a another simulation to give some velocity to the fluid.

For example if I turn this on we can see here are a couple different values.

We have the velocity source which can use a domain or it can use an effector.

So for this example we'll be using a smoke simulation and selecting that domain.

In this guide parents right here to demonstrate this.

Let's first take a look at our fluid simulation.

Right here we have a flow objects.

I'm going to enable fluid and set the type over to flow.

And then the flow type is going to be on liquid.

Here we can see we have that.

And then this is just a basic simulation.

The resolution is at 32 so it just bakes in a little bit faster.

And these are all just the default settings.

What we need to do now is set up a smoke simulation to do this.

I'm going to select the domain press shift D and then right click over in the outline or you can see

I named the fluid domain and the flow object.

So I'm going to go ahead and double click on this and call this one smoke and then domain just so we're

a little bit more organized.

And what I'll do next is I'll press shift a and add in a another cube.

This is going to be our flow object for the smoke domain I'll press s and z and scale it down just a

little bit and then over in the outline or I will also name this so we know exactly what we're doing.

Smoke and then flow I'm going to turn on fluid and set the time over to flow and we're going to leave

it as smoke.

And we're gonna set the behavior as in flow.

So how this works is the fluid will take the velocity of the smoke and it will kind of guide it going

upwards.

So the smoke is actually going to catch some fluid as it flows up and carry it with it all the way to

the top of the domain.

I'm going to drag the floor object below the fluid so it actually goes through.

And since we did that we also need to select the smoke domain and scale it up just slightly so the floor

object is still inside the domain.

I'll also scale it up just slightly so we don't get that jittery effect.

And there we go.

So with the smoke domain selected I'm gonna select the type over here to gas and the resolution will

leave at 32.

That's fine.

And the timescale I'm going to bring up to 1.

Now let's bake this in so I'm going to uncheck guys because we do not want guides for this simulation.

And then over in the cast settings we need to set two custom folders.

One is going to be for the smoke domain and another one is going to be for the fluid.

So since we're using the smoke I'm going to select that button on the bottom and navigate to a folder.

And as you can see here I have two different folders.

I'm going to select smoke and then click accept then we can bake this set.

This should go pretty fast because it's at a lower resolution.

And now if we play our simulation we can see it's working but it's not showing up because of the domain

saw select it and press H to hide and this is our simulation.

So now let's set up the guides in the fluid.

I'm going to press Ultra HD to bring back the domain and select it.

This is our fluid domain and I'll go over to the guides panel and open up this.

First off we're going to set another custom folder in the cast set in so I'm going to select that button

on the side and navigate to it since we are now dealing with the fluid.

I'm going to select the fluid domain on the side and click accept the end for him.

I will leave at 50 and then here in the guides panel.

We need to select the parents I'm going gonna select the smoke domain.

We have three different values here.

The weight the size and the velocity factor the weight is basically how strict the fluid will be to

the smoke.

So if you were to set this to a higher number the fluid will lag behind the smoke.

If you set it to a lower number this the fluid will be more attached to the smoke and it will follow

it a lot closely.

So I'm going to set that to a lower number so the fluid actually stays close the size right here is

basically the size of the guiding and if you said this to a bigger number there'll be more of the guide.

And if you set it to a smaller number it'll be a lot smaller.

I'll set it to a value of 4 just so it's a little bit smaller.

The velocity factor controls how much velocity the smoke will give to the fluid.

So if you were to set this to a higher number.

Basically what's gonna happen is the fluid will shoot straight up really fast and collide with the top

of the domain.

If you leave it at a lower number it will go a little bit more slowly up to the top.

I'm going to leave it at a value of two and I think that will work perfectly fine.

And then we can scroll up and click on bake I've noticed when baking in the guides it takes a lot longer

than usual.

So be careful if you're going for a very high resolution because you're baked can take a lot longer.

So now let's restart the simulation and press the play button and we can see this is how it looks.

It's taking the fluid and bringing it upwards.

Just like that and when you're looking at the domain if you notice a lot of red.

That means your particles are moving very very fast as we can see here we do have a lot of red.

So what we can do to fix that is free the data and maybe set the weight up to a value of 2.

So the fluid does lag behind the smoke just a little bit.

We'll bake that in and see how that looks.

The bake is done and now it's player simulation and we can see that does look a lot better.

It's a lot slower than it was and now what we can do is just come over here to the bottom and bake in

a lot more frames but you get the basic idea you can take a simulation and use it as some velocity for

another simulation and you can get some very interesting results.