Hi, dear flare team.
This topic seems to be very old now, however, since we have been struggling  for a long time, I think it is a brighter idea to ask you guys:)
As Ariel said previously, the cell shading effect can be easily done with an simple enviroment filter.
but the problem is how can we solve the problem that the enviroment filter dosn't display properly on a plane or any other flat surfaces. And also the result of using enviroment is not exactly what we want. we want the edge of the object to be displayed like a "brush stroke", or maybe even close to that. But currently, using enviroment filter, no matter how we modify the pic, it dosn‘t display very well, especaily  while the camera facing to a flat surface.

Did I miss anything to set the prameters of enviroment filter? and how can I get a fair solution, no matter what the object is (flat or whatever)?

Best

hi jason...i know you were waiting for this for a long time

we're really..."really" close to get the new version of flsl....and I did some examples about stroke edges...and they look exactly as you want ..we'll also post examples and tutorials about flsl on the wiki...as always!

about the issue that environment filter doesn't display well on flat surfaces...it's because the surfaces takes the color of the normals....and flat surfaces has all normals pointing to the same direction.....this is because we also have a planar filter...that does very similar thing to environment but works better for flat surfaces.