Blend Surface_help

[gmoreno.id (Gmoreno)]

Hi all,
I am trying to blend 2 surfaces… and I am not able to do it properly. I need a perfect blend, since this is going to be produced in CNC later on.

For the moment, I have done the surface between the fuselage and the wings, with NetworkSrf, since I am not able to use BlendSrf or any other command in the right way… what would you recommend?

This is the file (one side is done with NetworkSrf, and the other one is left in blank intentionally, so you can try the best solution.

Thanks in advance for your help.
GM

BlendSrf.3dm (7.7 MB)

[pascal (Pascal Golay)]

Hello - it looks like you’ve made your wing surface directly from a polyline - i.e. it is faceted in the forward-to-back direction.

Is that what you intend? I should think it will make your life much more difficult.

Your surfaces could be much, much simpler and smoother:

-Pascal

[gmoreno.id (Gmoreno)]

Hi Pascal!
You are right… An engineer has designed the airfoils for all the plane, and the first airfoil (attached) “curve - polyline” has 270 points. Since I would like to respect 100% all the points from the airfoil designed by him, I don’t want to change anything. What would you suggest? Is it better / easier to transform it?

[Stratosfear]

You can split into manageable sections, then rebuild those curves. Then use crvDeviation and point edit until you get an acceptable result. VSR’s curve approximation tool makes it much faster and easier to do.

[gmoreno.id (Gmoreno)]

All right… you have convinced me that I should rebuild the curves for the Airfoils, trying to get the best possible result.

Once this is done with the airfoil, what would you do? Use BlendSrf with the fuselage?

[gmoreno.id (Gmoreno)]

By the way… I guess VSR for Mac is not in the market any more, right? I have been trying to get it, but I don’t find it any more

[Stratosfear]

It’s gone. You can still do this within Rhino.

The big issue is your naca curve is made up of short degree 1 curves. You’re not going to build smooth surfaces from that. An easy method is to split your curve down the middle then rebuild it.

[encephalon]

i would rather use RebuildCrvNonUniform which ensures curvature continuity and i actually explained him that a while back in this thread he does not seem to remember i guess at least he does not seem to use it…

[Stratosfear]

Thanks. NonUniform did a much better job. Degree 3 with 15 points. With a bit of point editing I managed 0.03 mm CrvDeviation.

[gmoreno.id (Gmoreno)]

Thank you all… Pascal, Stratosfear, encephalon … very much appreciated!

I definitely will change the airfoils as you are explaining in this e-mail, in order to get smoother surfaces.

Just one more question… once I have my root airfoil with no more than 40 points, what would you do to blend it with the fuselage in the best possible way? BlendSrf?

Thx

[Stratosfear]

In your profile view start scaling/point editing your airfoil curve. To the shape that you intend for the fuselage blend. Then you can project that curve onto the fuselage and trim. Then position blend, match surface preserve isocurve direction the blend surfaces.