Creating a Landscape with Terrain

So far, we have used Cubes to generate our level prototype, but we also learned that those shapes sometimes cannot represent all possible objects we could need. Imagine something irregular, such as a full terrain with hills, canyons, and rivers. This would be a nightmare to create using cubes. Another option would be to use 3D modeling software, but the problem with that is that the generated model will be so big and so detailed that it won't perform well, even on high-end PCs. In this scenario, we need to learn how to use Terrain, which we will do in this first section of this chapter.

In this section, we will cover the following concepts related to terrains:

• Discussing Height Maps
• Creating and configuring Height Maps
• Authoring Height Maps
• Adding Height Map details

Let's start talking about Height Maps, whose textures help us define the heights of our terrain.

Discussing Height Maps

If we create a giant area of the game with hills, canyons, craters, valleys, and rivers using regular 3D modeling tools, we will have the problem that we will use full detailed models for objects at all possible distances, thus wasting resources on details we won't see when the object is far away. We will see lots of terrain parts from a great distance, such as mountains and rivers, so this is a serious issue.

Unity Terrain tools use a technique called Height Maps to generate the terrain in a performant and dynamic way. Instead of generating large 3D models for the whole terrain, it uses an image called a Height Map, which looks like a top-down black and white photo of the terrain.

In the following figure, you can see a black and white top-down view of Scotland terrain heights, with white being a higher height and black being a lower height:

Figure 4.1 – Scotland´s Height Map

In the preceding image, you can easily spot the peaks of the mountains while looking for the whitest areas of the image. Everything below sea level is black, while anything in the middle using gradients of gray represents different heights between the minimum and maximum heights. The idea is that each pixel of the image determines the height of that specific area of the terrain.

Unity Terrain tools can automatically generate a Terrain 3D mesh from that image, saving us the hard drive space of having full 3D models of that terrain. Also, Unity will create the terrain as we move, generating high-detail models for nearby areas and lower-detail models for faraway areas, making it a performant solution.

In the following figure, you can see the mesh that was generated for the terrain. You can appreciate that the nearer parts of the terrain have more polygons than the further-away parts:

Figure 4.2 – Height Map generated mesh

Take into account that this technology also has its cons, such as the time it takes for Unity to generate those 3D models while we play and the inability to create caves, but for now, that's not a problem for us.

Now that we know what a Height Map is, let's see how we can use Unity Terrain tools to create our own Height Maps.

Creating and configuring Height Maps

If you click on GameObject | 3D Object | Terrain, you will see how a giant plane appears on your scene and that a Terrain object appears on your Hierarchy window. That's our terrain, and it is plain because its Height Map starts all black, so no height whatsoever is in its initial state. In the following screenshot, you can see what a brand new Terrain looks like:

Figure 4.3 – Terrain with no heights painted yet

Before you start editing your terrain, you must configure different settings such as the size and resolution of the Terrain's Height Map, and that depends on what you are going to do with it. This is not the same as generating a whole world. Remember that our game will happen in the Player´s Base, so the terrain will be small. In this case, an area that's 200 x 200 meters in size surrounded by mountains will be enough.

In order to configure our terrain for those requirements, we need to do the following:

1. Select Terrain from the Hierarchy or Scene window.
2. Look at the Inspector for the Terrain component and expand it if it is collapsed.
3. Click on the wheel icon to switch to configuration mode. In the following screenshot, you can see where that button is located:
   

   Figure 4.4 – Terrain settings button

4. Look for the Mesh Resolution section.
5. Change Terrain Width and Terrain Length to 200. This will say that the size of our terrain is going to be 200 x 200 meters.
6. Terrain Height determines the maximum height possible. The white areas of our Height Map are going to be that size. We can reduce it to 500 just to limit the maximum peak of our mountains:
   

   Figure 4.5 – Terrain resolution settings

7. Look for the Texture Resolutions section.
8. Change Heightmap Resolut to 257 x 257:

Figure 4.6 – Height Map resolution settings

Important Note

The Heightmap resolution is the size of the Heightmap image that will hold the heights of the different parts of the terrain. Using a resolution of 257 x 257 in our 200 x 200 meter terrain means that each square meter in the terrain will be covered by a little bit more than 1 pixel of the Heightmap. The higher the resolution per square meter, the greater detail you can draw in that area size. Usually, terrain features are big, so having more than 1 pixel per square meter is generally a waste of resources. Find the smallest resolution you can have that allows you to create the details you need.

Another initial setting you will want to set is the initial terrain height. By default, this is 0, so you can start painting heights from the bottom part, but this way, you can't make holes in the terrain because it's already at its lowest point. Setting up a little initial height allows you to paint river paths and holes in case you need them. In order to do so, do the following:

1. Select Terrain.
2. Click on the Brush button (second button).
3. Set the dropdown to Set Height.
4. Set the Height property to 50. This will state that we want all the terrain to start at 50 meters in height, allowing us to make holes with a maximum depth of 50 meters:
   

   Figure 4.7 – Set Height terrain tool location

5. Click the Flatten All button. You will see all the terrain has been raised by those 50 meters we specified earlier.

Now that we have properly configured our Height Map, let's start editing it.

Authoring Height Maps

Remember that the Height Map is just an image with the heights, so in order to edit it, we would need to paint the heights in that image. Luckily, Unity has tools that allow us to edit the terrain directly in the Editor and see the results of the modified heights directly. In order to do this, we must follow these steps:

1. Select Terrain.
2. Click the Brush button.
3. Set the dropdown in Raise or Lower Terrain mode:
   

   Figure 4.8 – Raise or Lower Terrain tool location

4. Select the second brush in the Brushes selector. This brush has blurred borders to allow us to create softer heights.
5. Set Brush Size to 30 so that we can create heights that span 30 meter areas. If you want to create subtler details, you can reduce this number.
6. Set Opacity to 10 to reduce the amount of height we paint per second or click:
   

   Figure 4.9 – Smooth edges brush

7. Now, if you move the mouse in the Scene view, you will see a little preview of the height you will paint if you click on that area. Maybe you will need to navigate closer to the terrain to see it in detail:
   

   Figure 4.10 – Previsualization of the area to raise the terrain

   Important Note

   That checkered pattern you can see near the terrain allows you to see the actual size of the objects you are editing. Each cell represents a square meter. Remember that having a reference to see the actual size of the objects you are editing is useful to prevent creating too big or too small terrain features. Maybe you can put in other kinds of references, such as a big cube with accurate sizes representing a building to get a notion of the size of the mountain or lake you are creating. Remember that the cube has a default size of 1 x 1 x 1 meters, so scaling to (10,10,10) will give you a cube of 10 x 10 x 10 meters.

8. Hold left-click and drag the cursor over the terrain to start painting your terrain heights. Remember that you can press Ctrl + Z (command+ Z on Mac) to revert any undesired change.
9. Try to paint the mountains all around the borders of our area, which will represent the background hills of our base:

Figure 4.11 – Painted mountains around the edges of the terrain

Now, we have decent starter hills around our future base. We can also draw a river basin around our future base area. To do so, follow these steps:

1. Place a cube with a scale of (50,10,50) in the middle of the terrain. This will act as a placeholder for the base we are going to create:
   

   Figure 4.12 – Placeholder cube for the base area

2. Select Terrain and the Brush button once more.
3. Reduce Brush Size to 10.
4. Holding the Shift key, left-click and drag the mouse over the terrain to paint the basin around our base placeholder. Doing this will lower the terrain instead of raising it:
   

Figure 4.13 – River basin around our placeholder base

Now, we have a simple but good starter terrain that gives us a basic idea of how it will look from our base's perspective. Before moving on, we will apply some finer details to make our terrain look a little bit better. In the next section, we will discuss how to simulate terrain erosion with different tools.

Adding Height Map details

In the previous section, we created a rough outline of the terrain. If you want to make it look a little bit realistic, then you need to start painting lots of tiny details here and there. Usually, this is done later in the level design process, but let's take a look now since we are exploring the Terrain tools. Right now, our mountains look very smooth. In real life, they are sharper, so let's improve that:

1. Select Terrain and enable the Brush button.
2. Set the dropdown in Raise or Lower Terrain mode.
3. Pick the fifth brush. This one has an irregular layout so that we can paint a little bit of noise here and there.
4. Set Brush Size to 50 so that we can cover a greater area:
   

   Figure 4.14 – Cloud pattern brush for randomness

5. Hold Shift and do small clicks over the hills of the terrain without dragging the mouse. Remember to zoom in to the areas you are applying finer details to because those can't be seen at great distances:

Figure 4.15 – Erosion generated with previous brush

This has added some irregularity to our hills. Now, let's imagine we want to have a flat area on the hills to put a decorative observatory or antenna. Follow these steps to do so:

1. Select Terrain, Brush Tool, and Set Height from the dropdown.
2. Set Height to 60.
3. Paint an area over the hills. You will see how the terrain will raise if it's lower than 60 meters or became lower in areas greater than 60 meters:
   

   Figure 4.16 – Flattened hill

4. You can see that the borders have some rough corners that need to be smoothed:
   

   Figure 4.17 – Non-smoothed terrain edges

5. Change the dropdown to Smooth Height mode.
6. Select the second brush with a size of 5 and an opacity of 10:
   

   Figure 4.18 – Smooth Height brush

7. Click and drag over the borders of our flat area to make them smoother:

Figure 4.19 – Smoothed terrain edges

We can keep adding details here and there, but we can settle with this for now. The next step is to create our Player's Base, but this time, let's explore ProBuilder in order to generate our geometry.