Oh, I forgot ab internal islands... Then something like this procedure : convert your boundaries to regions, then do subtraction of all islands regions from main outer region... Then convert that main region to surface... Then finally iterate through all grid points and check weather line with start point (x y -1.0) and end point (x y 1.0) imprints that surface... If that's true imprint command have option to erase imprinted curve, so you should specify inside (command "_.IMPRINT" ... "_Y") - "_Y" - yes option to erase that curve... Then just do the check : (if (and li (vlax-erased-p li)) -> entmake grid point... - else if (li - line) exist, just (entdel li)... I know that this procedure is so sloow, but it'll do exactly what you need at the end... And no need for approximation : regions and planar surface created from region is accurate enough for curving representation...
