Load the source texture (bitmap or shader) you want to weather here. The most effective types of images are those that have definitive edge contrast. Otherwise the effect may end up being far too subtle (which can, however, also be the desired effect in some cases).
Use this setting to define the direction of flow of the water. This is the direction in which the colors will be blurred. For vertical walls, this is usually the value -U (down). U and V refer to the UV coordinates ,up’ and ,down’ on the textures Y axis.
A brief explanation of how the Weathering shader works:
For each piece of color information gathered from the texture by the algorithm, additional color information in the direction defined by the Direction setting will be gathered (sampled) and combined in conjunction with the Weighting setting. Intensity on the other hand defines the length over which the additional color information should be gathered. The smaller the value, the less the texture will be blurred. A value of 0% will disable the shader.
Note that the Smoothness will have to be adjusted depending on the texture used and the Intensity defined. In the example above, the Smoothness value had to be increased quite a bit because of the source image’s high contrast levels.
This value defines the amount of color information (see Intensity). The larger the value, the more subtle the blurring effect will be (but the render times will increase accordingly). However, very low values can also produce very interesting structured effects for most textures (not like the black-and-white texture the Intensity example but for more complex textures)!
3 modes are available:
If weathered colors extend beyond the UV borders they will reappear on the opposite side. Enable this option to prevent this from occurring.
Here you can load a texture with which the weathering can be controlled using grayscale values (black = no weathering; white = maximum weathering).
Use this value to steplessly adjust the amount of influence the texture in the Intensity Shader has.