How to smooth out a seam on the edge of a lofted surface?


I have a problem with a model I am working on. I have reduced the problem to a more simple one here.

I want to connect these two cylinders.

I am using the duplicate edge tool to create curves that match the mouths of the cylinders and copying a third curve to the middle.

After using the loft tool, I am happy with the shape. However the seams at the edges of the surfaces do not look too nice in the renderings I am producing of this model. Right now my solution is to smooth out the edges using Photoshop - not exactly a professional approach.

I read elsewhere you could drape a rectangle over the seam and trim the edges to smooth out the seam. I however wasn’t able to find information on how to do that exactly. Could some kind soul point me in the right direction?

(Pascal Golay) #2

Hi Eero - instead of duplicating the edges, use the edges directly in your loft, and set the start and end tangents in the dialog.


@pascal thats an interesting way of using the loft command, yet i still couldn’t get rhino to create a smooth surface between the 2 cylinders ?? @Eero creating a curve to sweep along was my way of solving this

(Pascal Golay) #4

Hi MIles - not smooth as in not tangent, or not smooth as in not an arc?



Hi Pascal, the surface I lofted [and set the start and end tangents in the dialog] between the 2 cylinders didn’t look good, a few small ridges etc, I just couldn’t get the surfaces to look as good as they do when I created the curve to sweep along,

(Pascal Golay) #6

OK - looking good and being tangent are two different criteria, but, it does work out better if the seams on the cyilinders line up nicely, or at least the seam points offered by Loft are set to align - the resulting surface will be simpler -

Also, control points are simple and adjustable - it depends on what you want to do. There’s always Pipe…


(Pascal Golay) #7

BTW, @Eero, I forgot to mention, MatchSrf can help here, after the fact.



the middle section of the cylinder bend seems to look a little deformed,

although where the lofted surface meets the cylinders looks great :slight_smile:

(Pascal Golay) #9

Right, that is what the tangent setting does - if you want more control over the shape,Sweep1, Pipe, etc… or add a circle to the loft out in the middle, as the original post shows.