Hello!
I’m modelling a vintage jet aircraft and it’s going really well. I decided to “rebuild” an old model I made years ago, now I’m seeing improvements.
With the attached model’s fuselage, and especially the nose I’m happy. But I’m having difficulty merging/joining/matching these surfaces. The shape is pretty much spot on. But I can’t seem to get all these surfaces to join while respecting the round intake shape and the round mid-fuselage shape.
Model.3dm (5.1 MB)
In case this is of any relevance..
The process I followed:
Then moving to the nose:
Hi Dave,
You make your life much harder by trying to model all these patches and then try to connect them. Even if it works, you probably have many difficulties getting a fair and smooth end result.
In my vessel ship hull training, I teach modeling single surfaces that are smooth and fair. As I don’t know which aircraft you try to remodel, I have the idea that you have to model the canopy as a separate single surface and then blend that into the fuselage.
A total other modeling strategy is to do the job with Rhino SubD and create a single SubD for the total plane or most part of the total plane. After modeling the overall SubD, you can convert it to Nurbs and add window details etc.
Good luck and enjoy your quest.
Gerard
Hallo Gerard, dankjewel!
It’s supposed to resemble a Fokker S.14 Machtrainer.
Maybe I can try to get the model down to a few cross-sectional curves and only Sweep2. However, many aircraft have compound curves and many complex connections that I see no other way than to build up from separate surfaces. I see they do the same a lot with cars and I’ve watched countless hours of tutorial but I keep bumping my head into the problem described..
By the way, the layer Canopy was only added to show the general picture and it’s not my main issue now. The layer Canopy basically covers an “ugly” bridge part that would be trimmed off later to create a solid.
Goedemiddag Dave,
Nice to see that you try to model a good old Fokker aircraft.
For me the Loft command is favorable over the Sweep2 command in order to get a surface with a minimum amount of control points.
In the attached example, I modeled an idea of the fuselage with Loft/Loose command in combination with record history (option at the bottom of your Rhino screen). The loft curves are circles that you can move and transform in order to get the desired shape.
Model-RhinoCentre.3dm (1.8 MB)
Hello !
I’ve been in-and-out of this project and I wanted to report that I redefined most cross-sections. I also added cones at the front and back of the model. I then lofted the model and did some basic control point editing. I made the loft tangent to those cones. I have to say, with history On, it’s quite a pleasant modelling experience!
I’ve spent some hours (again :)) looking at YT videos to correctly edit curves with Curvature graphs. Sometimes it looks like there is a “knot” in a curve I cannot get rid of.
It’s relevant since I cannot for the life of me get a decent blend between the wing and fuselage. Those Curvature graphs are all over the place and the resulting surface folds over on itself.
For info; The fuselage is three sections to ensure the mid-section is a pipe.
The wing profiles I rebuilt and re-edited because my chosen wing profile was full of control points (to make sure I have the most efficient aerodynamics, exported points from a database). But the “wave” at the trailing edge made for an impossible blend.
Thanks to everyone! I hope I’ll learn more because I’m not modelling now just puzzling and muddling around for hours and it’s becoming less fun 
“Insanity is doing the same thing over and over again and expecting different results”
I think your main problem is you are trying to wrap that blend around the trailing edge of the wing.
In the one image that shows the trailing edge it looks to me that the blend between the fuselage and wing just continues straight past the trailing edge and then you trim off a triangle from the blend. Then the trailing edge continues its fairly sharp radius where the blend surface was trimmed (see pic below)
In other words, the blend doesn’t wrap around the trailing edge, the trailing edge wraps around the blend.
I’m sorry but I’m having a hard time looking at the problem differently. Would you propose to blend the “easy” and relatively straight areas, then make separate surfaces for the leading- and trailing edges? I think this was one of my iterations but I can’t remember now I’ve tried so many times.
But you are exactly right, to make a NetworkSrf work I blended the wing trailing edge curve to the quad of the fillet on the fuselage. I also made those blend curves from ExtractIsoCurve to omit the separate edges on the fuselage (I did DupEdge for all separate trimmed edges, then Join to make a continuous curve).
What is the continuity level between the blends/fillets and the wing and fuselage of the physical aircraft? I strongly doubt it is curvature continuity. It may be tangent continuity but I doubt it was even exactly tangent continuity.
A lot of these shapes are covered in some tutorials by James Carruthers on this page: Rhino - Learn to use Rhino
Indeed, looking at some rare prototype pictures, it makes me think that sheet metal workers literally just “made it work”. However, as I’m intending to 3D print the model and scale it afterwards, I feel like all should be as smooth as possible..
Btw, I did copy the curves from the trimmed area at the fuselage, since the real one seemed like it has “position” continuity. So some form of line being distinguished should be okay.
Yeah it’s not even going to be tangent.
Wow impressive, especially that C-130 Hercules tutorial. Started reading and I’ll need to do it a few times. Very nice and detailed!
First of all I was only addressing what happens at the trailing edge (TE). It does look like the the blend wraps around the leading edge.
On the TE, even if what you are doing made a nice surface it wouldn’t look at all like what the picture shows is on the airplane. The trailing edge looks like it stays a sharp small radius until it gets pretty close to the fuselage.
Something like this:
wing.3dm (775.2 KB)
I make my wings out of a minimum of 3 surfaces maximum of 5. I try to make make them bezier as close to the naca data as possible. It makes blends like this much easier to do in pieces. Match surface preserve iso direction is a big help. Along with surface edge curves and insert knots. Check out Sky’s videos for great tips and tricks. https://www.youtube.com/thirtysixverts
I’m very thankful for all the help provided in the forum. So, thank you!
I worked a bit here and there on the model and applied the Lofting to get a better fuselage. Then, I rebuilt the wings as described in the C130 Hercules tutorial. It makes for such a clean profile without losing any resolution!
I continued with the fairing and tried two strategies:
Attached the model as is now.
One question already, I can’t understand why the BlendSrf creates the two hard “creases” or lines exactly where I added control handles. How can I clean this up?
Secondly, how can I make the NetworkSrf work? Again, these are typical problems I’ve never truly overcome over the years and are the " walls " I encounter.
Fokker S.14 Machtrainer fairing.3dm (3.7 MB)
How I created the blend & details control points as I moved them
Could anyone tell where I’m wrong and why that crease is there? I can’t “puzzle it away”
Maybe try something along those lines. Build the wing surfaces single span without trimmed edges. For the “fillet” contact curves on the fuselage, find the four points where the curvature starts to accelerate (see your original one-piece curve side on), and then draw two degree 6 or 7 single span curves between those points, then use two blend curves left and right (I did not spend time to match yours exactly). Then you can build a simple loft “fillet” towards the fuselage and match that G2. Then do the same on the bottom of the wing. Only then, when those two surfaces are as simple and clean (look at the CP structure) as possible, attempt the “peaky” surfaces left and right.
For even simpler “fillets”, consider building the long top and bottom surfaces in two parts, using a degree 5 section from the highest/lowest point of the wing edge to the fuselage.
