Creating a Wilting Leaf
Two shaders (B) Fresh Leaf & (A) Wilted Leaf are plugging into a (C) layered texture (Then the final output to (D)a surface shader). Then an animatable transparency ramp map is connected to the (B) fresh leaf shader, therefore (D) the leaf shader transforms into wilt leaf. (Revealing colour & Bump information from the (A) wilted leaf shader.) (Fig. 01)
Fresh leaf shader (B)
Pretty standard shading network as you can see. Lets get into the concept of ($) and (*) down below. (Fig.02)
Fresh leaf shader
Leaf_crack01 is a image file map (It is a painted map in Photoshop, the white areas are where it will wilt) connected to a ramp shader Wilt_Trans01.The black part in Wilt_Trans01 map is the part that has crumbled away. This map has to be plugged into both shaders (A),(B). (Fig.03)
Two files connected network
Out colour R to U,V Co-ord. As long as they are black & white map you can use others such as Out colour G,B.
By connecting the file texture to the ramp, you have a set up for animating values. If you want harsh edges between values, you can clamp the position of ramp like the Fig.05 images shows .
Closer look at (*)
Easy way of combining maps is by using layered texture. Wilt_Trans01 was made for the outline of the leaf geo.(so no need for extra detail modelling) Leaf_crack01 was a mapÂ painted for inside animatable transparency map
Bottom Wilt_Trans01 is first file to be middle click drag and drop on the layered texture. Blend mode is multiply (Fig.07).
Taking a look at maps (Fig.08).
Wilted leaf shader
Pretty self explanatory by looking at the Fig.09 image. yellow ($) concept is already explained on the above, so they are using same method and concept for spec, bump, transparency animation. Blue ($) is also same concept as yellow ($) except additional colour files I have connected to each ramp circles. (More detail below).
Closer look at blue($)
Fancy red star Anim_Ramp01 is the animation ramo that drives transparency, colour and bump animation. This way we do not have to animate everything all separately (Fig 10).
Rot_Color01 map is a colour map that is a key for wilted look of the leaf. Yellow halo and brown dried spot look is achieved with animating this map. After you connect Anim_Ramp01 to Rot_color01 like we discussed earlier, now you mid click drag and drop all three CL_01,02,03 into each ramp circles for the colours.
Find reoccurring patterns throughout the images rather than trying to copy what looks like from these images (Fig.11).
This image is used for Anim_Ramp01 which I explained above. White areas are the parts that will turn brown and yellow. White dots were so we see yellow, brown speckles all over the leaf (Fig.12).
Transparency map for the leaf that rots and crackles away. White areas are where geo will become transparent for illusion of a leaf crumbling away (Fig.13).
Patterned colour map
Had to repeat UV four times to get the desirable effec (Fig.14).
Like I explained in the beginning (A) and (B) two shaders gets combined by layered texture (C) which connects to Surface shader (D). Don't forget to plug inÂ transparency map into the final surface shader (D). (Fig.15)