Original subtitles

Hello everyone.

And in this video we're going to take a look at collisions in the fluid simulation to enable a collision.

You need to select an object and go over to the fluid tab select it in the underneath type.

You need to send this over to effector.

We can see here the effector type is currently set to collisions.

We can see collision and then we can see guides guides is a little bit more complicated and we'll get

into that in a later video.

For now we're going to look at collisions.

There are only two options for collision objects.

We can see is plainer.

And once again if you are using a plane or something that is completely then you're going to want to

turn this value on since this is an enclosed mesh that has some thickness.

I'm going to leave this value off.

We also have surface thickness and this will give a invisible border around the mesh.

And if I was to turn this value up the collision box would probably be around here instead of right

on the mesh since I want it to be right on the mesh.

I'm going to set the surface thickness to a value of zero.

Now let's go ahead and bake in this simulation to see what this looks like.

So I'm going to click bait data in the domain settings and since we are using a collision we can see

it's baking a lot slower now.

The bake has finished and now we can play a simulation and we can see this is working properly.

It's colliding with the monkey head.

We'll go ahead and play that one more time just like that and it's going all the way around

now before this video ends.

I do want to take a look at the is playing our value right here a little bit closer and how this works

is it deals with objects that are non manifold.

And what that means is objects that don't really exist or can't exist in the real world.

This plane right here can not exist in the real world because it is completely flat.

So what we need to do with objects like this is we need to turn this value on.

Now if we turn this on it's not going to work.

What we need to do is also turn up the surface thickness.

So if we were to set this to a value of about zero point one we can now bake in our simulation and this

should work properly once it makes to a hundred frames we can player simulation and we can see it's

still going through the mesh.

In that case we need to turn up the surface thickness even higher.

So let's go with a value of about point four.

Now if we select our domain free this data and bake it again this should work if it doesn't.

We are going to need to go even higher.

So now if we play our simulation we can see it is working and it's colliding with the surface of the

plane.

So if you're fluid objects are going through.

You do need to churn up the surface thickness.

This will help tell blender where the surface is and it will accurately display the fluid simulation.