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View Full Version : Making a fillet at the intersection of 2 complex curves



rpleak
04-26-2018, 04:46 AM
I'm trying to model the intersection of a wing to an aircraft fuselage, and I can't figure out how to do a smooth fillet between these two intersecting curved surfaces. I've made the wing by extruding a Bezier curve and would like to do a smooth tapered fillet where it intersects the deformed cylindrical fuselage, but just cannot figure out how to do with Modeler. Is it possible with the native Modeler tools, or would I need to buy a set of 3rd party plugins, such as LWCad?

Thanks!

prometheus
04-26-2018, 11:57 AM
we need images, and I donīt understand why you made the wing by extruding a bezier curve..but that is not important as long as the final wing mesh is ok.

rounder or using chamfer several times may work, but itīs hard to tell without images.
and I am not sure if you are working with actual spline curves at this stage of the model, or true polygon mesh?

erikals
04-26-2018, 03:08 PM
it is actually a bit tricky...
no good plugins for that at the moment

fortunately / unfortunately, one of the better ways is doing it manually

(bottom image is a good example)
https://www.renderosity.com/mod/forumpro/?thread_id=2872876

prometheus
04-26-2018, 04:17 PM
it is actually a bit tricky...
no good plugins for that at the moment

fortunately / unfortunately, one of the better ways is doing it manually

(bottom image is a good example)
https://www.renderosity.com/mod/forumpro/?thread_id=2872876

It may be a better way to actually extrude out from the cylinder body to ensure a good straithg flow out..keep extruding then scale and move til you got your wing, if you have made a wing part with curves, you could perhaps use that as a guide in background layers, this way you donīt need to worry much of how the parts fuse, just use rounder or chamfer then at the junction which should be pretty clean.

If you wanīt more advanced complex curves and filletting, I would guess the new lw cad nurbs is one way to go, or if you should spend money with lwcad, maybe invest in a nurbs software rhino etc.

rpleak
04-26-2018, 09:54 PM
My apologies for not being more specific, and providing images. I'm using an extruded Bezier curve, because that's the only way that I know of to accurately reproduce the proper curve of an airfoil. The first image is an example of the type of blending of wing into fuselage I would like to be able to do. Image 2, shows the end of the extruded Bezier wing. Image 3 shows the error I get when I try to use Rounder to round off the edge of the wingtip.

I don't know where to start to be able to try to get a smooth fillet between the wing and the fuselage. Any suggestions would be greatly appreciated, as I've never had to model anything like this before.

Thanks;
Rob Pleak


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rpleak
04-26-2018, 09:59 PM
Thanks, I'll check out both LWCad and Rhino and see which one I might be able to afford, if they will help me do the job.

prometheus
04-27-2018, 03:55 AM
Thanks, I'll check out both LWCad and Rhino and see which one I might be able to afford, if they will help me do the job.

One approach may be..considering this seem to be a more mechanical model you want? unless you go subpatch..which I would recomend otherwise, a way would be to create your model in designsparks mechanical, it is free but requires registration..but
it has great filletting tools, though it is build in in to the pull tool which you use to highlight edges then move drag to make the fillet, or enter values numericly, it is parametric and can be changed at any time and allow for varied size fillets ends on the same edge.

export can be made to obj and then import to lightwave, I would so like to showcase designsparks and demonstrate things, but got too little time, look for designsparks mechanical youtube vids.
other than that..rhino is excellent as nurbs modeller, but may be expensive and taking some time to learn, while designsparks is easier to get going and for free..though it isnīt the same approach with nurbs.

MonroePoteet
04-27-2018, 06:00 AM
I'd definitely use subpatches, if possible. To create an airfoil in subpatches is a very simple polygon mesh:

141426 141427 (converted to subpatches with TAB)

Because the profile of the base polygon mesh for the airfoil is only four pairs of points front to back, it becomes easy to extrude an Airfoil from a Hull mesh using "e" to use Extender Plus to "duplicate" the working polygons each time, and then Move (t) and Scale (h) and Rotate (y) to shape the airfoil:

141429 141430

Obviously, this is a 2-minute model and not intended to be accurate, but the points comprising the polygon mesh can be easily moved, stretched and rotated to produce the shape you want / need, using Knife (SHIFT-k), Extender Plus (e) or the various edge tools to add more edges if needed.

I've attached the basic LW2018 polygon mesh models.

mTp

OFF
04-27-2018, 09:49 AM
Metamesh:
https://m.youtube.com/watch?v=ctESAMUQYv8

Tim Parsons
04-30-2018, 12:33 PM
My apologies for not being more specific, and providing images. I'm using an extruded Bezier curve, because that's the only way that I know of to accurately reproduce the proper curve of an airfoil. The first image is an example of the type of blending of wing into fuselage I would like to be able to do. Image 2, shows the end of the extruded Bezier wing. Image 3 shows the error I get when I try to use Rounder to round off the edge of the wingtip.

I don't know where to start to be able to try to get a smooth fillet between the wing and the fuselage. Any suggestions would be greatly appreciated, as I've never had to model anything like this before.

Thanks;
Rob Pleak


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That's way to many polys to deal with. Subdivision surface modeling is they ticket here.

Kryslin
04-30-2018, 03:56 PM
Also, and I remember this being said in multiple places, rounder does not like to operate on an open edge, at all. Since I'm away from my workstation, I couldn't test whether or not LWCad woul crash on rounding that.

I would have done this in SubD's, working from the wing root out. Once I got the basic shape, I'd use 3rdPowers bandsaw tool to insert hold edges to help sharpen and straighten things out. Once I got that half of the fusealage done, I'd mirror it, and be done.

Rhino 3d could do this, easily. It's a little pricey for a special fillet tool for Lightwave 3D, though. However, if you need mechanical accuracy, It's good. I've used it for casting, corebox, and pattern design in the past, and watched patch an 8 border curve patch with only a little difficulty.

erikals
04-30-2018, 06:32 PM
polyflow suggestion for SubD

https://i.imgur.com/VTTyFMC.jpg