Over the years we’ve seen 3D tools gradually creeping into 2D animation, allowing complex camera moves and special effects to be accomplished easily while still retaining the ‘2D’ look of ink and paint on celluloid. To get that ‘cel look’ from a 3D app such as Maya can be nearly impossible without the aid of a plug-in, and Cambridge Animation has produced just such a plug-in, Animo Inkworks, so that Maya animators can create that 2D look easily with the tool they know best.
Inkworks is a group of plug-ins including cartoon shader, which lets you control the placement of Ink and paint on the model, set colours and other functions, and an Animo Renderer plug-in for rendering ink lines. You can use the Maya renderer to render the Inkworks-shaded objects, but you won’t get any ink lines on the final image. Other plug-ins provide an export function to send your Maya scene to CAS’s Animo 3D World program and importing animation data from 3D World back into Maya.
Installation is quick, though it’s necessary that three Maya files be removed and replaced with modified versions. The old ones are stored in a folder for safe keeping, but you’ll need to replace them manually if you uninstall Inkworks. Inkworks also needs a FlexLM licence in order to run.
Using Inkworks is simple. Apply the shader to your model, adjust it to get the required look and render. The basic parameters in the shader are Base colour, Shade colour and Highlight. Rather than shade the model using smooth graduated colours from shadow to highlight, the shader blocks in the illumination; a single colour for highlight, another for diffuse and another for areas not illuminated.
There are a number of other parameters that modify the three main sections of shading; ‘Opacity’ for shade, colour and highlight and ‘Level’ for Shade and Highlight. The Level parameter defines exactly where on the model the shade colour stops and the diffuse begins. This is also the case for the diffuse/ highlight transition. The highlight boundary can be controlled using a Blending parameter, so you can have razor-sharp highlights or fuzzy ones.
A ‘Show Lit paint’ toggle enables coloured
lights to affect the paint in the shader, so that a red spotlight would produce red highlights on a model. Disabling this assumes all lights to be pure white. The ink section of the shader is more complicated, since it may not be obvious to the software where you want ink lines to be, even though it is to you. Ink can be put around the outline but also in ‘folds’. A Fold angle control, much like a smooth shading angle, sets the minimum angle between polygons where it’s decided by the software that a fold should be inked. Setting this to 0 would ink every edge in a polygon mesh.
Inkworks works pretty much as you’d expect. Most geometry types are supported though not necessarily by the Inkworks renderer itself. A texture can be applied to most of the channels of the shader but when rendered in Maya it will contain the smooth gradients of the texture. You may therefore have to first create a texture with the right ‘cel look’. One limitation is the lack of any intelligent texturing of the ink lines for a more sketchy look. They’re rendered as solid lines, and if set too thick you can see the corners of each discrete line.
Inkworks copes well with producing a cell look within Maya. It’s expensive but if you use Maya and need a 2D look, Inkworks does the job.