As promised what feels half a century ago, I now have the correct and working template for creating Unity3D URP/HDRP Terrain Layers, with Diffuse, Normal and Mask Map.
Substance Graph
Of course this is only the rough template. It also just converts the inverted graymap from the input bitmap node for smoothness (0=rough, 1=smooth) and sets metal to 0 (no metal). You will have to change that depending of the type of terrain layer you create. (obvious, but I thought I just say it).
But the mask generation is now 100% working, I tested it thoroughly.
This is a very naive approach to the wonderfull world of Unity3D Terrain System.
I played around with it for a long time, did some cool things with it, like on-the-fly bomb craters via script and stuff.
It actually is time now to do this a bit more focused, since I am planing to use it in my game Tanks with Legs. For doing so, I started a laboratory session with Unity3D 2019.
First thing I want and need to do : Take a Mesh and put it on the terrain surface like a coat. I need this for my procedural level generator streetmap generator to make the streets or paths align to the height of the terrain.
But I ran into some problems while doing so and noticed I have to fresh up on a few things. I will do this very slowly and document it here.
Put a grid on the terrain
First thing I want to do is to put a grid of sphers on the terrain, on the same height as their world position on the terrain.
I setup a new GameObject and put a script on it which I named TerrainGridder.
First thing I need to know is which terrain to use, which is done by a public Terrain field so it can be assigned in the inspector.
Now I need to get the pivot world location of the terrain and then the dimensions of the terrain. Since the dimensions in the transform of a terrain is (1/1/1), this is not really usefull.
On a normal GameObject you would use the bounds of the Renderer Component, but since a terrain has no renderer (at least not by default or as component), you can use the size field of the terrainData field of the terrain. This field holds a vector with the dimensions of the terrain in worldScale.
With the method getHeight of the terrainData object of the terrain I can get easily the height of the terrain at a (x/z) world position.
So after using this code :
for (int y = 0; y < gridSize; y++)
{
float ypos = (terrainDimensionsInWorldScale.y / gridSize) * y;
for (int x = 0; x < gridSize; x++)
{
GameObject sphere = GameObject.CreatePrimitive(PrimitiveType.Sphere);
float xpos = (terrainDimensionsInWorldScale.x / gridSize) * x;
sphere.transform.position = new Vector3(xpos, terrainToGrid.terrainData.GetHeight((int)xpos, (int)ypos), ypos);
}
}
I have this grid on the terrain :
Grid on Terrain made with my little TerrainGridder script.
But if I change the height of the spheres using the retrieved y height with the terrainData method, it is nor working as excepted :
So what am I doing wrong here ? Let me investigate.
So first of all, it seems that I should use terrain.SampleHeight and not terrain.terrainData.GetHeight.
So with this code :
for (int y = 0; y < gridSize; y++)
{
float ypos = (terrainDimensionsInWorldScale.z / gridSize) * y;
for (int x = 0; x < gridSize; x++)
{
GameObject sphere = GameObject.CreatePrimitive(PrimitiveType.Sphere);
float xpos = (terrainDimensionsInWorldScale.x / gridSize) * x;
sphere.transform.position = new Vector3(xpos, terrainToGrid.SampleHeight(new Vector3(xpos,0,ypos)), ypos);
}
}
I get the result I wanted as first step.
The grid of spheres is now perfectly aligned on the y-axis according to the terrain height. With this I can start part two of the TerrainGridder : Taking a mesh and changing the height of its vertices to the height of the terrain.
