Issues using surface from network of curves

I am currently trying to create the exterior surface using a network of curves however the end result distorts the surface to protrude further than the reference curves. I was just wondering if someone might be able to take the time to provide some feedback on some possible issues and solutions regarding this matter please.

Sample.3dm (12.5 MB)

NetworkSrf creates surfaces which are curvature continuus everywhere. Your curves have multiple locations where straight sections tangent with curved sections but not curvature continuous.

This shape could be made by in three parts

The large, parallel sided part can be created using Loft between the first and last cross-section curves with the same shape. Or ExtrudeCrv one of the cross-section curves.

The flat nose can be created using PlanarSrf. The curves defining the boundary should be cleaned up though.

The transistion can be created using Sweep2 with the surface edges as the rails and the section curves. Some curve clean up may be needed.

Hi David,

Thank you for taking the time to respond with your feedback.

I have created the large section and flat nose following your suggestions.

However I was wondering if you can please clarify what you mean when you suggest to clean up both the boundary and section curves ? Is this the reason when using Sweep 2 Rail the end result produces a distorted surface finish.

Sample.3dm (394.7 KB)

you can increase the tolerance to approach the shape as close as possible to the curves!
for( NetworkSrf) all the curves must be open or closed in the u or v direction
you cannot have curves open and others closed at the same time in one direction

Probably not. You can use “Add slash” to control how Sweep2 links the two rails. See Help for more information.

But even with a tighter tolerance NetworkSrf will not exactly match curves with curvature discontinuities.

yes I see what you mean,
if the curves have g0 contunuity for example, (networksrf) cannot reproduce such an internal contunuity in the generated surface

I think Dave Dagenham is looking to have continuity in the surface

The result of NetworkSrf is always G2 (curvature) continuous. The result is a single bi-cubic non-rational NURBS surface without multi-knots. @davedagenham input curves are G1 continuous NetworkSrf cannot exactly match the input curves.

Thank you for your feedback. You have both provided a lot of valuable insights for possible solutions for me to experiment with on this model.