Creating a Waterfall Material

This is a Tutorial to create a Waterfallmaterial.

The Normalmap

For a waterfall you need a Normalmap which Refracts the light so that the things behind it gets distorted.
I used The_GIMP with a normalmap plug-in for this Tutorial.
We create now a solid Noise so you go to Filters → Render → Clouds → Solid noise
you have to set the x value to 16.0(the highest possible) the y value between 1.0 and 3.0
the Detail to 15(highest possible) and you must check the Tileable box to make it seamless.
Now it should look similar to Pic1.

Pic1

To create a Normalmap with it you should read Normal_Map_Creation_in_The_GIMP
And use for Scale a value of 9.0.
After you converted it to a Normalmap it should look like Pic2.

Pic2

The Material

The basic Material

At first you have create a materialfile(vmt) and name it waterfall.vmt or similar. In the materialfile you should use the LightmappedReflective shader:

"LightmappedReflective"
{
}

So we don't need a $basetexture but we need a $RefractTexture and optionaly a $ReflectTexture.
The attribute for the $RefractTexture parameter is _rt_WaterRefraction and for $ReflectTexture is it _rt_WaterReflection.
Now it should look like this:

"LightmappedReflective"
{
	"$RefractTexture" _rt_WaterRefraction
}

That is now the base of our Material.
Now we add the Normalmap with $normalmap and the path to it like "nature/waterfall_n".
For the right refraction amount we add $refractamount with a value between 0 and 1 like 0.08.
Now your vmt should look like this:

"LightmappedReflective"
{
	"$RefractTexture" _rt_WaterRefraction
	"$normalmap" "nature/waterfall_n"
 	"$refractamount" .08
}

$Surfaceprop

You should add "$surfaceprop" "Water" for correct effects and physics.

Scroll animation

When you use your material in a map you should see that the refraction looks frozen, so now you must add a "Scrolling" effect.
You can do this with an animated texture or the easier way you add "Proxies" like this

"Proxies"
{
	"TextureScroll"
	{
	}
}

For the TextureScroll Proxy we need "texturescrollvar", "texturescrollrate" and "texturescrollangle".
With "texturescrollvar" we specify the target like we need "$bumpTransform".
With "texturescrollrate" we specify the scrolling speed you have to test yourself which value could be the best, I used 1.3.
With "texturescrollangle" we specify the moving direction in degrees we use 270 degrees for it, for a down flowing.
So now the whole vmt should look like this

"LightmappedReflective"
{
	"$RefractTexture" _rt_WaterRefraction
	"$normalmap" "nature/waterfall_n"
	"$refractamount" .08
	"Proxies"
	{
		"TextureScroll"
		{
			"texturescrollvar" "$bumpTransform"
			"texturescrollrate" 1.3
			"texturescrollangle" 270.00
		}
	}
}

Optional: Reflection

When you want Reflections you must add $ReflectTexture, $reflectamount and $fresnelpower. Use for $fresnelpower a value of 5 because I think it looks the best. For $reflectamount you must find your own value because there is no "Perfect value".

"LightmappedReflective"
{
	"$RefractTexture" _rt_WaterRefraction
	"$ReflectTexture" _rt_WaterReflection
 	"$normalmap" "nature/waterfall_n"
 	"$refractamount" .08
 	"$reflectamount" .3
	"$fresnelpower" 5
 	"Proxies"
	{
		"TextureScroll"
		{
			"texturescrollvar" "$bumpTransform"
			"texturescrollrate" 1.3
			"texturescrollangle" 270.00
		}
	}
}

TODO

• embeding into a map
• convert the normalmap to vtf format