All language subtitles for 05. Diffusion & Viscosity

Hello everybody.

And in this video we are going to look at the diffusion in the domain settings that a fusion allows

you to change the thickness of the fluid.

You can make it really thick or you can make it really thin just like water over in the settings we

have in base and an exponent and these values control how thick the fluid is.

There is also a preset option.

If I open this up we can see there's three different values and you can also create your own presets

by hitting that plus sign if we take a look at the default settings.

This is currently like water.

The base is set to 1 and the exponent is set to 6.

If I select water you can see as the exact same thing if I select honey we can see it's a little bit

different.

The base is now set to two and the exponent is now set to three.

This will give us a little bit more thick fluid and how this works is the base and the exponent.

There is a big equation to figure out exactly how to change the fluid.

If you're like me and you don't really like doing math too much you can go ahead and open up the blender

manual and look at this.

Here we are in the blender manual and you will look on the right side you can see there is a lot of

different presets on the different types of fluid.

You can see those also two different panels right here.

Dynamic viscosity and then climatic viscosity.

This one is the one that we need to use in blunder.

This dynamic viscosity deals with real world but this one over here deals with a blender.

So we're going to take a look at the blender numbers and then import those into the domain.

If we look over and melting glass we can see we have a base of one and an exponent of zero.

So if we wanted to have a fluid simulation like melting glass that is what we would put in to the diffusion.

So you can think of it as this with a high base and a low exponent.

You can get some thick fluid with both low numbers you will also get some thick wood but it will look

a little bit different with that knowledge and mind let's go ahead and jump back over to blender and

what I'm gonna do is set the base up to a value of six and the exponent down to a value of 1.

This will give us a really thick fluid.

We also have the real world size and this deals with the domain size.

So you want to think about what you are trying to create.

If you're creating a coffee mug you're going to want to set this to a low number.

This deals with meters.

So if I was to set this to 1 it would treat the domain like it's one meter long.

If you are creating a pool you're going to want to set this to a higher number like four or five meters.

So I'm going to set this to a value of four and then the surface tension.

This deals with this tension on the surface of the fluid.

You can see the differences on the different values of how it changes.

Basically it adds some stiffness to the top of the fluid it makes it look like it has a lot of tension.

I'm going to set this up to a value of twelve.

Setting it to a high value though will give us some strange results on the fluid.

It'll make it look really jittery.

So to counteract this we can turn up the maximum sub steps over in the top settings over here.

So the time steps I'm going to bring that up to a value of five for the maximum.

And then I'm going to bring this up to a value of three for the minimum.

This will take a little bit longer to bake but it will minimize that jittery ness that we see in the

surface tension.

Then if we wanted to save this preset we can hit that plus sign.

But currently I think this is bind because if I hit the plus sign and I just give it a name we can call

it thick fluid and hit.

OK.

We can see we get an error right here.

If I was to switch this back over to water and then try to go back over to the thick fluid we can see

this is not what we put in.

So we need to bring this back down to one.

And I think currently it's just bugged and the preset saving preset option is not working so you'll

just have to put in the numbers manually with those settings in place though we can go ahead and bake

in this simulation to see how it looks.

If we scroll up and hit both data we can see it's starting to bake down here but since we are using

a higher time step it is taken a little bit longer than usual.

The bake has finished and now I hit the spacebar we can see how this looks.

You will notice that the fluid it looks a lot more thick.

It's not just coming down here and splashing up.

It's actually slowly moving across.

So you can use this method of the diffusion to create like lava or something really thick like that.

And if we had the space for one more time we can see that is what it looks like.

So there you go that is the diffusion and in the next video we will take a look at the guides.