Network Surface - Different results - Help please


2 surfaces using the same curves. The blue surface uses 3 cross section curves. The purple surface uses 2 of the same cross section curves. The resulting surface using Match Position is different at the first cross section curve (layer color purple).

Does this mean that the first curve is effected by several non touching curves back? (hope that makes sense).

Why would the blue surface “fold” and not maintain it’s position with this first curve, yet the purple surface does?
These are the same curves. (note: they are not perfectly smooth since they are representing something as-built).


Network Surface.3dm (523.9 KB)

(Pascal Golay) #2

I don’t know how it’s working that out exactly but I would make an InterpCrv there if you want to control the shape. In general NetworkSrf does a lot better if the areas to fill are not very long and skinny- that is, give it a ‘reminder’ curve across the long, narrow spans.


(David Cockey) #3

Is the difference “real” or due to display mesh differences? Try refining the display mesh and see if the difference remains. I opened your attachment and there appeared to be a gap between the curve and the blue surface where the arrow pointed. I refined the mesh and the gap was much smaller.


it’s real… ExtractIsocurve in the V direction on the blue surface and you’ll see it hooking/folding.

what pascal said about doing an InterpCrv through the middle does eliminate the problem


Thanks guys!! I tried to follow the help guide with InterpCrv, but can’t understand how it works. Any example when someone has time would be appreciated. Thanks!


InterpCrv draws a curve which passes through the points you click.

using the midpoint osnap might not work out so well on your actual drawing without rebuilding those colored curves first. so try the ‘near’ osnap with interpCrv then click on the middle of each of your colored curves.

include this new curve in your network surface. it will tell it not to hook around at the end.

I’m not quite sure how smooth of a surface you can expect without redoing the profile but if they need to be that way then they need to be that way.

(on a phone-- can’t upload a drawing :wink: )