Closing complex geometry while preserving shape with G2 continuous surfaces

Hi guys,

In the disclosed figure, I have shown the surface I want to close.
I want to blend the vertical surface below the gap to the vertical surface above it and keep the shape of the horizontal surface on the left as long as possible. I’ve made a BlendCrv in the middle to clarify the shape I want to preserve. I want to blend the surface from top to bottom all the way from left (where the horizontal offset is high) to right (where the horizontal offset is zero) and make sure this happens smoothly. The surface should be curvature continous everywhere.
I have already tried closing the gap using Loft, BlendSrf, Sweep2, NetworkSrf and combinations of those, but they did not give the desired result of a smooth surface.

I hope to hear some good ideas!

Edit: I updated the working example, thanks to @ra_mull and @Stroopwafelandcoffee

BlendProblem(1).3dm (240.4 KB)

I started to take a look at your file, but your surfaces don’t actually line up in places.
The file is joined below, but there are magenta area’s which should be connected. This could be why you’re not getting the results you’re hoping for.

I’ll take a look at this a little later and see if I can help.

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I had a go at fixing the geometry. This should now be a workable example problem:

BlendProblem(1).3dm (240.4 KB)

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This is by no means perfect. But I would think if you draw some lines in your top view and project them onto the surface then use blendcrv to get some more profiles to run a network surface with. Run your network surface with “record history” on and then you can point edit your curves to change the shape of your network surface to get rid of any kinks.

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Yes, thanks for your reply! That will work to give a smooth surface. However, I am still looking for a robust method that will easily give the same preferred shape for similar geometries, as I have to make this shape multiple times for subtly different geometries.

Hello- a couple of things I’d change -

It’s not completely clear what is going on with this surface:

Is it meant to be flat in the flattish section? It looks like it is, but it gets messy at one end:


I’d make a plane if the surface is meant to be planar there and add simple transition surfaces at either edge rather that try to do it all as one surface:

You’ll have some things to resolve at the skinny end but I’d think you can control the shape much better by breaking these types of shapes up.


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Thanks for your reply! Yes, it is supposed to be flat in the flattish section and the surface to fill the gap with is supposed to preserve the shape of that surface for as long as possible. The problem though is that it can’t be flat near the skinny end as you call it, so there it has to be one surface and that is the toughest part to blend smoothly.

mhh, have you deleted a similar topic before? Still, you don’t model blends and fillets first and then trying to fill the rest. That’s overcomplicating everything.

Hi, yes I’ve deleted my previous post as it was too vague.
That’s not what I’m doing. The start is the upper and lower vertical surfaces and the horizontal surface is only to show the shape I want to preserve.