Loft Curves

Hi all
four curve will make a proper surface only if they feed to loft flipped.
something happening inside “Flip Curve” component less or more like magic
although some other set of curves make a desired result without flipping.
could you help me to find what should be checked to see if a curve needed to be flipped or not before loft.
thanks. (31.8 KB) (21.3 KB)

but the rebuild curve has same effect which rebuild parameter of loft has , both will ruin the kinks and there will be no more primary shape . as you see i tested with setting kinks to True in divide curve.
below is rebuild with 1000 n.


Start points and direction. In this case, I used Seam to align start/end points to their first discontinuity point. Point List indicates they all have the same direction.

When I broke the curves at their discontinuity points and lofted the sections, some are surfaces and some are breps, which suggests anomalies in how the curves are created.

Loft_2024Apr19a (26.6 KB)

For what it’s worth, you can rebuild the section curves (purple group) and keep the points. (28.8 KB)

P.S. Fit Curve instead of Rebuild Curve can result in fewer control points when you relax the tolerance (‘Ft’ input) to 0.1 or thereabouts.


God Send Josegh
this was great but what if some of curve in between has no discontinuity point?(may i have to make another problem-recipe-gh)

You know just and only Dr’s say this nowadays :ok_hand:

@Quan_Li is first exploding the curve, then rebuilding each segment, and finally joining everything back together

“suggests” or “anomalies”?

both together

give me a favor and check this new set of curve please (49.2 KB)

let me investigate more on that approach

I don’t have time right now to look at this, maybe in ~two hours… but this is a problem :exclamation:


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The most obvious thing about these curves is that they are poorly formed. GIGO. Pottery Barn rule applies (“you break it, you own it”).


Other things to say is that the longest curve of the four is at the bottom instead of the top. They do all have the same direction though. Good luck, I’m not interested in getting these to loft.

try @Quan_Li’s method. it should work

I am very thankful for your help.seam adjusting was great learn. those poorly curve came from built in hit-and-miss offset.

The problem with new curves is that they have more segments or less segment than previous ones and at end rebuild will convert a few big artifacts to many small artifacts . Ill try that way and post the result .

“It’s a poor craftsman who blames his tools”

Seriously, there are so many ways of doing things. This isn’t perfect but much better, eh?

White curves are yours, the lofted red curves are mine. As usual, parameter values affect the results. (51.6 KB)

Did you consider lofting only two curves (top and bottom) instead of four?

@Quan_Li is like a master architect of knowledge, demolishing the curve with explosive intellect, meticulously crafting each segment anew, and ingeniously reassembling the pieces into a masterpiece of understanding.

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Well it’s fail since it is rely on making surface based on 4 edge not 3 edge and seems this is the key of chest.

Honestly i am not like that, its more like a woodcutter with just an old axe here😅