This work will demonstrate the ability to get a high resolution close up quality by adding several features to create a material using Renderman.
Final Render
  The Final result using Renderman. See below to see how this effect was achieved.
Original Palm With Generic Material
  This is the original palm. It has a simple blinn material with a small amount of translucency applied in Maya.
Color Ramp
 

First i built a color ramp that the colors could be controlled by the artist in Maya. Using the spline function.

surfcolor = spline (t, baseColor, frontColor, tipColor);
Lines on the Leaves
 

I added what will be the veins using smoothsetep I also added intensity control to the veins so they can be made lighter or darker.

float ss = mod(s * veinFreq,1);				
varying float stripes = (smoothstep(0.2,0.25,ss) - smoothstep(0.75,0.8,ss)) * veinIntensity;
Break up the Specular
 

I Multiplied some noise into the specular color to break up the highlight to make the plant look la little rougher.

float specNoise = noise (s * noiseFreq, t * noiseFreq) * noiseAmp;
speccolor = Ks * specular(nf, i, roughness) * hilitecolor * specNoise;

 
Adding Bump
 

I added bump to add some slight texture to the plant. Both the frequency and the amplitude are adjustable.

float bumpNoise = noise (s * bumpFeq, t * bumpFeq) * bumpAmp;
N = calculatenormal(P + normalize(N) * bumpNoise * Km);
Apply the Shader to The Plant
 

I applied the shader to the plant in maya and adjusted the color ramp by adding more of the colors I wanted to see.

	surfcolor = spline
				(t, baseColor, baseColor,
				frontColor, frontColor, frontColor, frontColor, frontColor, 
				tipColor, tipColor, tipColor, tipColor, tipColor, tipColor, tipColor);
Translucency
 

In order to test the translucency of the shader I made the front color red and the back color blue. The result is the translucent areas are purple. Translucency is added with this code:

color	diffuseFront = diffuse(nf);
color	diffuseRear = diffuse(-nf);
color	diffuseTotal = (diffuseFront * frontRamp) + 
		(diffuseRear * translucency * backRamp - stripes);
Final Shader
   
 

Over all I am happy with the resulting shader. It is fairly customizable allowing the stripes, the colors, and many other things to be changed in Maya by the artist. I however was not able to get the veins/stripes to run the full length of the leaf. I thought it was a uv problem but when I made new UVs it had the same kind of problems. I also would like to be able to add the ability to adjust the colors weight in the ramp in Maya. I also seemed to loose my bump effect when the translucency was added.

 

Click Here to see the entire shader code.

Click to return home