Hi Lars - well definitely an offset of your existing surface will not produce those kinds of edges, due to the shape of your surface.

Offsets of a surface happen along the surface-normal direction.

If you look at the Front-side view of your object, this is what it looks like:



I've drawn a couple of lines in there to indicate the surface normal direction along the silhouette.

With the surface normal pointing off to the side like that, the offset surface will be created along it and will be off to the side as well. That's basically the definition of what an offset surface is.

For a sphere, the normals are pointing upwards, like this:



That's why the sphere creates vertical edge pieces, because the sphere's surface normals are pointing vertically there.


So anyway, that's why Offset/Shell will not create what you are looking for in this case.

Other than creating a custom surface using something like Network, I guess you could try to create an extended version of your surface and then offset that and try trimming all that back to an edge...

I'll try to take a look at your shape and see if I can suggest any other way.

- Michael

Hi Lars,

If you could post or e-mail me the more complete piece you showed above:



That might help me give some better suggestions.

It's otherwise kind of hard for me to visualize how the pieces are supposed to fit together.

- Michael

Hi Michael, now you've provided me with a lot of knowledge and I thank you very much! I sat down to make an image so I could show you what it is I'm trying to do, and now I feel like a complete idiot...

Last night I tried this but it took forever and ever and still no shell. Must say that MoI performs excellent in these cases, it doesn't hang or freeze, it just calculates and if you wish to abort you just click cancel. This is great.
I believe it was rather my laptop that was tired last night. But now it works. This is what I've tried to do all the time.

I cannot join the two halves, left and right, but MoI could still create a centerline shell. The maximum shell thickness is 0,25

Will try the Network command, that together with the sweep tecnique you showed me would possibly give me more control over the way the edges look.

/Lars

Hi Lars, I just sent you a PM as well - I think the "secret step" in this case will be to not use Shell to create your final surface.

Instead use Offset, but don't attempt to offset the surface - it will not create the kind of edges you want since it will follow the surface normal as I wrote previously.

Instead offset each of the curves that you used to Loft your surface in the first place. Then loft a new one through all of those new offset curves.

This does not create an offset surface - and actually the outside and inside surface will touch each other along the vertical axis line.

But it seems to be pretty close to what you are after:



This seems like a better strategy to pursue.

- Michael

Hi Michael, thank you for sharing the secret.. This gives me the kind of edges I was looking for.

/Lars

Added to the Sepecial Thread Gallery (before a cool rendering :)

Have you a 3dm of that?

Hello Frenchy, it's meant to be "rendered" in real life like a sculpture. But if you can do a cool rendering I'd be happy to send you the 3dm.

/Lars

@renklint
A cool rendering I don't know but surely funny image!!
Don't sent now!
I will recall you in 10 days !

Hi Lars, it is looking great! I hope you will be able to post a photo when it is built.

- Michael