Yess, offsetting is a very important function. However, I can't get the results. After an offset, I end up with a curve which contains MANY more segments. And the subsequent loft is twisted again. Sighhh. I have to play with it a bit more.
Cheers
Lemo

Hi Lemo,

> However, I can't get the results.

You mean on the same curves that you posted before, or on a different set of curves?

On the curves that you posted before, I needed to do the steps to split up the original curve so that it matched the offset segments.

If you're talking about a different set of curves, please post them as well and I can give you some more recommendations and steps on how to process them. But it will likely be the same steps I showed above about using Trim to split up the original curve into matching segments.


> After an offset, I end up with a curve which contains MANY more segments.

There isn't really any way around this - when your offset creates sharp corners you will get segments between each sharp corner piece. So you need to split up the original curve into equivalent segments.

- Michael

Same curves. The offset function is 'subdividing' smooth curves as well, the result is that the 'forced' edges are lost and the artifacts are visible again. If I create new curves following the offset generated ones and add points where I would like to force edges according to the underlying original, then it works again. But that is a LOT of work. I downloaded TSplines last night and that deals with this problem perfectly.
Cheers
Lemo

Hi Lemo,

> The offset function is 'subdividing' smooth curves as well, the result
> is that the 'forced' edges are lost and the artifacts are visible again.

I don't quite understand - you mentioned using the same curves, but are you doing another offset? That means making a new curve... If so if you can post your new curves with the new offset that might help me figure out what is happening. But in general I'd recommend doing the splitting after you have done all the offsets.


> If I create new curves following the offset generated ones and add points
> where I would like to force edges according to the underlying original, then
> it works again. But that is a LOT of work.

Really? Over here it only took me about a minute's worth of work to adjust your original model so that it lofted well.


> I downloaded TSplines last night and that deals with this problem perfectly.

Great, I'm glad you have found a good solution!

- Michael

I'll post some screen shots later....
And yes, a lot of work. Some of my objects have about 50 lofts.... And to edit every one... sighhhh
And no, TSplines is not the answer. It can loft nicely as it does not seem to reply on the underlying control points, BUT it cramps up at other limitations. There is not way to affect the subd weights and creasing is a pita. Not the ultimate answer... I guess I have to go back to Silo and continue to 'loop' around with that.
Lemo

Hi Lemo, I see - yes if you need to create a large number of these things it will take a while.

Since you have Rhino you may want to use Rhino's Rebuild command on your offset curve to reconstruct them with a single smooth curve, you will need to use a lot of points to make the new curve follow along your original though.

There is usually not any single super-easy "one button push" type solution to making a loft between many different pieces with different numbers of segments and corners in them work very well. It will usually require some manual tuning and even possibly working with smaller pieces at a time.

If you want to post some more examples of problems you're running into I may be able to give you some additional tips.

But a complex model made up of 50 different pieces, each of which lofts through mutli-segment curves.... I'm sorry but it is just normal that it will take many hours of work to produce such a model...

- Michael

Thanks for your never ending stream of hints and support! Yes, I will continue to tickle the beast ;).
However, there is one thing where I wonder if there is a fast way to do it. And that is to 'puff up' closed curves/ flat surfaces. Like a soap bubble surface which is inflated. I tried the rail revolve which is pretty cool, but fails when you have segments like a star fish.
cheers
Lemo

Hi Lemo - slightly raised type relief type shapes are pretty hard to do in MoI right now, except for the ones that work well with Rail revolve.

You might try making a bitmap file version of your outline and then fill it in with a gradient and use ZSurf to create a heightfield type surface from it, see here: http://moi3d.com/forum/index.php?webtag=MOI&msg=602.7

I usually tell people that relief work is best done in a program like ArtCAM that has more specialized tools specifically oriented towards puffed up or bubbly type designs.


Since you have Rhino you could also give Rhino's Patch command a try for this type of thing. Either create some additional inside curves that you pull up in Z, and then patch through all of those, or extrude your outline upwards and patch the top open edge (instead of the original curve) so that tangency in the Patch will create some force in the z direction to make it bubbly. Probably the first way with additional curves is better though - the additional curves do not need to be closed, they can be a kind of center line running down the middle of your shape.

Patch will fit a single large surface that kind of curves and twists to pass through points sampled on the curves that you input.

It can be kind of fussy in several ways, like if you have a thin starfish arm it can tend to get kind of lumpy and imperfect in narrow areas that don't have enough fitted surface control points to make the surface flexible enough in that small area. Increasing the "Surface U spans" and "Surface V spans" will create a denser surface with more control points in it which can help with that.

I do plan on having a Patch type command in MoI in the future but it will be missing it for version 1.0 .

- Michael