Hand Drawn Line Quality.
We were seeking the line quality of hand drawn animation: a shaky line, occasional gaps lasting for one frame, slight variation of line thickness. The unprocessed clip below shows a Maya Software render. The flower is made with Paint Effects on a curve. The dog and butterfly are 3d models with Toon shader, converted to polygons for better aliasing control. Some experimenting was done with animating the line in Maya via procedural noise mapped as line width and offset but that turned out to be unreliable when multiple objects were present in the scene.
Finally we decided to animate the line in AfterEffects, applying two passes of Turbulence Effect with different settings and Sharpening.