Hi all.
This is done by using curvature graph on extracted edges with history on:
60fps , but the “hairs” are not normal to the surface … this was doable also in Rhino 7.
This is curvature graph directly on SubD:
LESS than 1fps, “hairs” normal to the surface (incredibly useful! in theory…) … Rhino 8 feature.
Even if this were with decent fps, the huge amount of (wrongly scaled) hairs and graph, clogs the visual and make it hard to properly read the shape.
This should be RH-58162
I asked already elsewhere, but I’m asking again here:
Please, can we have this new feature works per-edge-selection?
Having it working only with whole SubD object is not usable.
Only being the curvature graph on, no command active, the viewport go at almost 1 frame every 2 seconds! (and it often give up, showing only the boundingbox for every object)
This is a SubD of 1932 vertices, 3841 edges, 1904 faces , with symmetry on …
This would be a godsend feature for surfacing, modeling… what’s Rhino about!
But implemented this way… unusable 
PS negative hair scale would be useful to work from the opposite side of a surface/subd , please consider.