Help with Fairing Solids

I am building a large scale RC model of the Blackburn Buccaneer, a UK 1950’s-1990’s jet. In order to get an accurate model, I am first building a 3D solid model in Rhino v4, which I can then section and develop the internal structure.

I have developed solid models for the wing, engine nacelles and fuselage body. The wing to nacelle has a very pronounced blend, and the fuselage to nacelle junction has a similar, but smaller blend.

I am having trouble building the blend areas. I have used Solid/Fillet Edge/Blend Edge, but not happy with the surface, and I can’t convert it to a solid I can then Boolean join to the nacelle/ wing solid object. It is a similar issue with the smaller fuselage/ nacelle blend.

The nacelle/ wing blend has a 5mm radius at the trailing edge and a 100mm radius at the leading edge. The fuselage/ nacelle blend has a 10mm radius.

My goal is to get a single, watertight, solid model of the fuselage/ nacelle/ wing to use as a basis for further model construction.

Rhino model of the fuselage/ nacelle/ wing attached. Fuselage and Nacelle.3dm (4.7 MB)

Requesting help from the Rhino experts.

Thanks

Paul

Hi Paul - it’s notto be a PITA that I say this but looking at your model, there is a LOT that can be simplified in terms of the geometry and get better fidelity to the design - I think you’ll be happier in the long run if you back up and look for better ways to get the surfaces you have.

If you work in wireframe viewports you can get a clue as to the surface structure and I would say this model is massively over-complex:

While at the same time not having very fair surfaces:
image

I realize this does not get your fairing done - but just as a sort of heads up. Griping aside, I would not rely on filleting etc to get your fairing done cleanly - I’d say these are surfaces that should be built ‘by hand’ with careful choices of where to trim the surfaces etc. I’ll attach the only example I have that has a similar transition - you can see that it’s relatively simple as far as the surfaces themselves go.

MC72_geoV4.3dm (3.6 MB)
@pbloxham - V4 file now.

-Pascal

1 Like

Pascal,

Thanks for the comments. I am an absolute self-taught Rhino beginner, so stumbling through the process.

The wing section you highlighted was generated with a lofted curve through a set of points from an airfoil database and I did not subsequently fair or simplify the curve. I then used the Sweep2 function along the leading and trailing edge lines to develop the wing solid.

For the fuselage and nacelle, I 3D scanned (high resolution professional scanner) a 1/72 model kit and then manually built cross-section curves from the scan mesh which I then developed a contiguous surface from using NetworkSurface.

Thanks for the file as an example, but I only have Rhino v4 and cannot open it. If you could save it as v4 I would appreciate it.

For the blend, are you suggesting manually defining a few cross-section lines and using NetworkSurface to build the surface - I’m not following your workflow suggestion exactly.

Regards,

Paul

Hi Paul - can you post the curves used? My guess of the moment is that apart from the unfair wing profile (different problem, fixable), you’ve used too many curves throughout, in modeling your shapes.

-Pascal

Pascal,

Thanks for the help.

Based upon your comment about building the fairing by hand, I managed to get a very good fairing developed using sections and NetworkSurface. Very happy with the result. I can’t get the individual solids to boolean join, but the result will be good enough for my purposes.

Updated file attached which includes construction lines.Fuselage and Nacelle 2018-06-28.3dm (10.6 MB)

I would be interested in any advice you can offer.

Kind Regards,

Paul

Hi Paul - I’d still urge you to make simpler surfaces - for example, that fairing - and I don’t know what data you may have that you’re trying to hit - that makes a difference - but to be curvature continuous along the wing and nacelle, that surface only needs six control points - your surface has close to 50 across. With that many points, if it is not perfect, then you’re toast- there is no way you can make surface adjustments and keep even close to fair.

I’ve monkeyed a little here with making some simpler surfaces - part of the fairing and parts of wings where I found some curves to fair. I don’t say any of this is the right or done, but just to get you pointed in a simple-surface direction.

Fuselage and Nacelle 2018-06-28_PG.3dm (7.5 MB)

-Pascal

Pascal,

Many thanks. I’m on vacation for the next week with no access to my Rhino computer, but I will look at your update when I return.

Regards

Paul