This short tutorial covers how to create an old, worn 'illustrative' sketch-style using the toon shader to create the above image. It covers how to use the base_tonemap and edge_detection in combination with bump mapping using a noise shader to create a hatching effect. Thanks to Javier Garcia-Lajara Herrero for the use of his convent model.

• Start off by assigning a toon shader to the geometry.
• Change the filter_type to contour (Arnold render settings). Without it, you will not be able to see the toon edge shading in the render.
• Reduce the specular_weight to 0 as we do not want any specular shading in the render.
• Create a skydome_light and render the scene. It should look something like this.

Edge Detection

• Reduce the angle_threshold to around 20 (toon-> edge_detection). This will give us more detailed edges around the geometry.

• The Edges appear too thick and black. We can fix this by reducing the Edge Width Scaling to around 0.4.

## Base Tonemap

• The Base shading looks too dark for the illustrative effect that we want. We can adjust this by using a ramp to determine how the Base shading is affected by the lighting in the scene. Connect a black and white ramp to the Base Tonemap and increase the amount of white in the ramp until it looks like the image below.

Without base_tonemap	B&W Ramp > base_tonemap

Hatching (Noise Shader)

Next, we will add a hatching style to the toon edge. To do this we can bump (or displace) the surface.

• Connect an Arnold noise shader to geometry -> normal (bump mapping) in the toon shader.
• Increase the number of octaves to 8. Reduce the scale in Y to 0.01. This will stretch the noise in the vertical direction and give the impression of a hatching effect.

Noise scale: 1	Noise scale Y: 0.01

• Try experimenting with different noise shaders/settings to get different hatching/stippling effects.

Cell1	Wispy
Billow	Perlin

_{Various Noise shaders -> Bump Mapping}

Final Rendering

• Connect an HDR map or a physical_sky to the skydome_light.
• You could also add a pale yellow base and emission_color to the toon shaders to give a worn paper effect.
• Try adding a similar shading effect to the sky using a polygon plane behind the geometry as used in this case.

_{Final shading network}