-Rebuild (with MasterCurve) while retaining the original shape

Continuing the discussion from Complex Sweep2 (How to solve):

Pascal showed me a method that solved the problem by using -Rebuild with the option SelectMasterCurve. He was able to rebuild the curve in such a way that it had only 6 control points but retained its original shape. I have been unable to replicate this so far. Is there anyone that can explain to me how I should approach this issue?

Hi Luc - I did not do anything special other than use the master curve option. I selected one of your curves as the ‘master’ to impose its structure on the the duplicated edge curve. This makes it so all the shape curves match, and have that nice structure that is in your curves without including these curves in the rebuild - that is, I only rebuilt the one small curve from the duped edge.


Wow, this is very weird. It actually works perfectly well on this specific example. I’m currently working on a new problem and as far as I know it doesn’t work their. I will soon update this topic with my problem there.

newProblem.3dm (210.7 KB)

Ok so currently I am trying to deal with a new problem. Here it doesn’t quite work. Do you know why?

So, on this one, the Rebuild is not enough - you need to Match the result to the surface edges and adjust with EndBulge- BUT, since your desired curve structure is degree 5, 6 point uniform curve, it is probably easier to use BlendCrv there (“Edges” option) and adjust the shape inside that command, rather than mess with the Rebuild.
newProblem_PG.3dm (302.5 KB)

(BTW, you can Match the shape curves directly to the surface edges - I see that you added some projected lines to the wing surfaces to match to.)


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The BlendCrv with Surface Edges is looking very promising. I’ll let you know how it went.

Ok so I kind of cheated my way out of it, but it worked really well.

So the 5th order was an accident, so I set those curves to 3rd order.
Then I used the -Rebuild, And used Sweep2 with the new Edge Curve.
I then trimmed of the last bit and used a NetworkSrf tp finish the last part of the surface,
It’s not very elegant. But for all intents and purposes it gets the job done.

You helped me a lot Pascal, couldn’t have done it without you. Thanks!

Hi Luc- I’m glad it worked out, but it still seems like too much fussing - here’s the result I get from just sweeping to the nice end curve.

newProblem_PGSrf.3dm (297.9 KB)


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Only one problem. Joining the surfaces results in a naked edge. Since this shape will be put through a CFD solver, it won’t be accurate enough…

Ah, ok - one way to clean up is MatchSrf there for tangency and 'Match by closest points, ’ ‘Refine match’ set and “Preserve isocurve direction” as well before sending it out


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Thanks again!

It still tries to solve the problem in a bit of a sloppy way. Resulting in a kink in the surface (MatchSrf):

Hi Luc - It looks to me, from the image, like the match is moving things far more than should be needed - that is, the edge is not very close to begin with - it should be almost spot on. Just the sweep gets the edges to within .00015 here.

newProblem_PGSweepOnly.3dm (219.1 KB)


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Yes, I still made a mistake somewhere. I managed to get it done in the end. I’ll give this a go and hope that the CFD analysis won’t trip over it. Thanks Pascal.