Hello everyone and welcome to a new section.
This one is about creating graphs for our modern house.
At the moment, it's just a dirt lawn
and that doesn't look very good.
So let's add in some particle
systems and create the grass.
First. In this video,
we're gonna talk about how to add in a way paints so we
can actually determine where we want the grass to be.
It's important to do this because
all the way over here on the right side,
the camera is not going to be able to see this.
That means we don't need a bunch of particles over there.
That's just going to slow down the render.
So I'm going to show you how you can limit
where the particles are using weight paint.
To get started, we need to select our object and then go
over to the object mode and
switch it over to the weight paint mode.
You can see everything is blue.
That means there's gonna be no particles.
If we assign this vertex group to the particle system,
how weight paint works is it deals with values from 0 to
10 is the blue color.
And if I start to paint,
you can see red is the a value of one.
The grain is probably about halfway,
maybe a value of about 0.5.
So that means there's going to be
about 50 percent of the particle density in that area.
I'm going to Control Z that well,
we're actually going to do is use the gradient tool.
We don't need a ton of particles in
the background because you're not
going to be able to see that very well.
So we're going to create a gradient effect where
most of the particles are going to be closer to
the camera and then it slowly fades
as it goes back to the brick wall over here.
To do this, we're gonna go into top view.
And then we're going to position
our view right about here.
Where you can do is select
the gradient tool with a strength of one for the weight,
we're going to click and drag all the way back here.
Something like that.
I might actually do that one more time.
So I'm going to click the gradient tool,
click and drag until it's right about there are so,
so we get some nice blue in that area.
Then what we can do is grab the brush tool,
set the way all the way down to 0,
and then paint out where we
don't need the particles to be.
We're gonna go into camera view by hitting 0.
And then we're just going to go along
the wall right here and paint out what we don't need.
Some shortcuts that you need to keep in mind is
F is to change the size of your brush.
You can move it out here if you want
a bigger brush and then you
can just click and drag to paint away.
I'm going to dry my brush a little bit
lower though, and then zoom in.
What we can actually do instead of painting
all of this because that's going to take a long time.
We can go into edit mode,
then switch over to the vertices select mode.
You can press Alt 8 to de-select and then click and
drag where the vertices are that are outside the camera.
You can also press Z to go into wire-frame.
And then we'll do the same thing over here.
We don't really need those vertices.
And then we don't really need
these vertices in the middle.
So I'm going to click and drag using circle,
select, something like that or so.
And then also we don't need any
of the vertices there air that are in the back.
So we're gonna go into top view.
And then I'm going to press B for box select and
draw a box around all of these vertices.
And then also we don't really need any of these vertices.
So we'll go back into camera view,
box, select all of those,
and then just use circle select
and grab all of these ones.
Just like that.
So now that we have all of
the vertices that are outside the camera view,
we can remove that vertex group from these vertices.
We need to do this by going over to
the object data panel.
Then with this vertex group selected,
we're going to click Remove and
that's going to remove the vertex from that.
So now if we go out of edit mode
and back into weight paint mode,
you're going to notice that everywhere is blue
except for the parts that we select it.
Now that that's out of the way,
we can start working on the particle system.