XSI Tutorial
Incidence Toon Rendertree
by Dave Lajoie
davelaj@videotron.ca
davelaj@softimage.com

For this tutorial, I wanted to show the "power" of the incidence node.
This node computes the angle difference between the camera and the object's surface.
I use an incidence to drive an color_interpolate node which allow me to ink the contour of the object's surface.
The color "back" is used when the surface is pointing away from the camera and color white is used when the surface points in camera direction.
I use the illumination shader "flat_light" to give a little toony look.
Then I blend illumination and color interpolate inking into one single result using a Mix2Color node
To control the ink thickness you use the incidence exponent and/or the color interpolate weight1 and 2 to select the location where the white to black transition starts.

Enjoy!
Dave.

Update! James Rogers has created an updated material preset based on this tutorial. It has two incidence and flat light nodes wich means one can make black lines but still input the correct colour in both flat light nodes for the main colour. Download it here: Toon2.zip or use the Netview Friendly Shader (drag and drop into SOFTIMAGE|XSI)here: TOON2

Rendertree:

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Shader Parameters:

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