Hide/show terrain programmatically

Question

How to hide/show terrain and other gameObjects during run-time (by C# code)?
I want to show/hide terrain and gameObjects in a fade-in/out style

Answer 1

The Terrain script uses a built-in shader by default. This one is not accessible nor modifiable.

Material mat = terrain.materialTemplate;
Debug.Log(mat==null); // True

Assigning a custom shader is limited to the Nature shader and none offers the use of Color. It seems in general that the terrain ignores the color of a shader.

    Material mat = terrain.materialTemplate;
    Color c = mat.color;
    c.a = 0.5f;  
    mat.color = c;

This will show the modification in the shader color but no effect on the terrain itself.

As a result you would have to create your own shader, like this one http://wiki.unity3d.com/index.php/TerrainTransparency