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Hello everyone and welcome to a new section.

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This one is about creating graphs for our modern house.

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At the moment, it's just a dirt lawn

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and that doesn't look very good.

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So let's add in some particle

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systems and create the grass.

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First. In this video,

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we're gonna talk about how to add in a way paints so we

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can actually determine where we want the grass to be.

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It's important to do this because

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all the way over here on the right side,

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the camera is not going to be able to see this.

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That means we don't need a bunch of particles over there.

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That's just going to slow down the render.

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So I'm going to show you how you can limit

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where the particles are using weight paint.

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To get started, we need to select our object and then go

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over to the object mode and

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switch it over to the weight paint mode.

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You can see everything is blue.

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That means there's gonna be no particles.

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If we assign this vertex group to the particle system,

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how weight paint works is it deals with values from 0 to

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10 is the blue color.

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And if I start to paint,

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you can see red is the a value of one.

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The grain is probably about halfway,

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maybe a value of about 0.5.

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So that means there's going to be

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about 50 percent of the particle density in that area.

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I'm going to Control Z that well,

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we're actually going to do is use the gradient tool.

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We don't need a ton of particles in

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the background because you're not

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going to be able to see that very well.

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So we're going to create a gradient effect where

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most of the particles are going to be closer to

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the camera and then it slowly fades

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as it goes back to the brick wall over here.

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To do this, we're gonna go into top view.

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And then we're going to position

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our view right about here.

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Where you can do is select

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the gradient tool with a strength of one for the weight,

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we're going to click and drag all the way back here.

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Something like that.

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I might actually do that one more time.

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So I'm going to click the gradient tool,

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click and drag until it's right about there are so,

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so we get some nice blue in that area.

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Then what we can do is grab the brush tool,

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set the way all the way down to 0,

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and then paint out where we

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don't need the particles to be.

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We're gonna go into camera view by hitting 0.

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And then we're just going to go along

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the wall right here and paint out what we don't need.

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Some shortcuts that you need to keep in mind is

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F is to change the size of your brush.

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You can move it out here if you want

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a bigger brush and then you

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can just click and drag to paint away.

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I'm going to dry my brush a little bit

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lower though, and then zoom in.

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What we can actually do instead of painting

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all of this because that's going to take a long time.

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We can go into edit mode,

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then switch over to the vertices select mode.

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You can press Alt 8 to de-select and then click and

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drag where the vertices are that are outside the camera.

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You can also press Z to go into wire-frame.

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And then we'll do the same thing over here.

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We don't really need those vertices.

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And then we don't really need

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these vertices in the middle.

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So I'm going to click and drag using circle,

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select, something like that or so.

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And then also we don't need any

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of the vertices there air that are in the back.

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So we're gonna go into top view.

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And then I'm going to press B for box select and

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draw a box around all of these vertices.

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And then also we don't really need any of these vertices.

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So we'll go back into camera view,

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box, select all of those,

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and then just use circle select

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and grab all of these ones.

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Just like that.

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So now that we have all of

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the vertices that are outside the camera view,

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we can remove that vertex group from these vertices.

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We need to do this by going over to

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the object data panel.

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Then with this vertex group selected,

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we're going to click Remove and

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that's going to remove the vertex from that.

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So now if we go out of edit mode

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and back into weight paint mode,

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you're going to notice that everywhere is blue

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except for the parts that we select it.

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Now that that's out of the way,

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we can start working on the particle system.