This is more a geometrical modelling question rather than a technical question with the software. I hope its alright to post it here.
Haven said that, this is the issue: suppose I have a topographical model of a cliff, which varies in z, I have contours, the surface, the solid (patch surface capped at the bottom). I cant find a method to extract the “top edge” (red in picture) of the cliff. Anyone that can give me a hand thinking this through?
Any ideas? The problem basically is that if I use contour lines, these do not connect across the z axis, so a manual connection needs to be done, which does not produce the best of results:
And if I work with the surface or mesh it seems like a step backwards in the direction that I want. Because extracting the “edge” seems a very abstract concept when talking of a surface like this.
Indeed, its tricky. Yes there is a change in slope in the edge, thats why the contours dont really help that much do they?
I was thinking something like finding the closest point between each successive contour line, splittiing the curves on those points and then divide the curve to create points. So I could interpolate the division points + the closets points to create and edge… in theory.
Start with the mesh rather than the contours. (Unless that mesh is built from the contours, try to find a more detailed terrain mesh model)
Create vertical “contours”
Move along the domain of each vertical contour and measuring change in slope, mark all positions above a threshold value.
Cull the false positives (points that seem out of place and aren’t really useful, ledges for example)
Connect the dots
