Find out how you can simulate painterly hand-drawn effects for your 3D projects with this fantastic tutorial by Richard Yot
In Photoshop create a new document at 512 x 512 pixels, and then create a custom brush with rough edges and in the Color Dynamics section of the Brush palette set the Foreground and Background Control to Pressure. This will give you a painterly brush that will modulate between black and white depending on how hard you press. You’ll find the brush used here has been supplied with this issue. Using this brush fill your canvas with strokes going up and down.
With the basic sketchtone painted (or alternatively drawn, scanned, or sampled) we now need to create a seamlessly tiling version for use in modo. Because of the hand-drawn nature of these, it’s best to do this manually rather than using automated methods (although Painter users might be able to use the pattern maker to draw a tiling sketchtone). Use the Offset filter to place the seams in the middle of the canvas and paint over them with the custom brush.
In modo it’s now a case of creating a suitable scene, in this case we adapted one of the sample scenes that comes with the program (in the Samples folder, the Organic subfolder) called skull.lxo. For NPR rendering it’s usually best to turn GI off so there’s a decent amount of contrast for the shadows, and in this case we also disabled the area lights and just used a simple direct light.
Once the scene is ready, the sketchtone can be applied. Since it’s applied as a shader, you have the option of only applying to certain items or materials, or to the entire scene. With the UV option checked it will follow the contours of the geometry according to the UV map. You can selectively edit the UVs by scaling or rotating individual UV islands to control the size and direction of the applied map.
With the sketchtone applied you will want to adjust the lighting in your scene, move the lights around until they give a pleasing mix of light and shadow and then you can adjust the parameters of the SketchTone shader itself. The Tiling Amount, Angle, as well as the Brightness and Contrast controls are all very useful for organising the effect. If you would rather not use the UV Mapping option, then simply tick the Screen Co-ordinates checkbox.
At this stage we add a Gooch Tone shader to create the brown colour palette, with the cool colour (which represents the shadows), a dark reddish brown and the warm colour (which represents the lights) as a much lighter beige-brown. We then tick the Use Lights option in the Gooch material for it to respect the scene lighting. You can optionally also add a Cel Edges shader if you want an outline around the geometry.