momodot opened this issue on Aug 13, 2009 · 5 posts
momodot posted Thu, 13 August 2009 at 2:10 PM
BB... this is intriguing to me... in the early 90s I read an academic paper about a "cartoon" algorithm developed to transmit video of people using sign language in real-time over 300baud phone lines. The idea was that as "edge detection" has never worked at extracting line drawings from images since drawing done by humans don't locate the lines at the edges of abrupt value shifts in a gradient but instead the human draws edges in the "weighted center" of the gradient valley as the mind imagines this is where the edge likely falls spatially even if the actual edge is hidden by the ramp of gradient value. The algorithm looked at the gradient ramp and attempted to calculate where to place the the edge based on the weighted center point... they said this some how was analygous to how the brain extrapolates the edges of contour based on identifying the edge as the point on a surface most oblique to the viewer... this reminds me of Fresnel maybe?
Anyway... could you think about this... I have played alot with toon shaders and edge blenders but what I have not succeded at doing is getting Poser to render the edge finely along the polys most oblique to the camera while still visible, is the fresnal or some other node a better choice than the edge blender for trying to place the rendered line on the polys that are almost perpen
Miss Nancy posted Thu, 13 August 2009 at 2:22 PM
the poser edge-blend node (camera fall-off shader) will produce good lines whether in poser itself or via photomanipulation, but one case in which it doesn't always work is at the lines along front-facing box edges. it works better on smooth surfaces like balls or humans.
momodot posted Thu, 13 August 2009 at 2:27 PM
I have a few cartoon shader sets but have never been able to cox somethinhg like a line drawing from them... even thin they just kind of "blot" in the shading of the form. I need to show examples but can't right now... I gave up on toon shaders and just started rendering with the texture plugged into the ambient chanell with an edge-blender.
momodot posted Thu, 13 August 2009 at 4:24 PM
momodot posted Thu, 13 August 2009 at 4:33 PM