Direction arrow causes naked edges in sweep 1

I am doing a simple “Sweep1” with a closed curve. When I do a “What”— I do not get a closed polysurface. I have tried moving the direction arrow, and, flipping directions. I always get naked edges where the arrow was placed. What am I missing?

Can you post the curves?

I have never tried to post a file before—hope this drag & drop works…

Example Panel.3dm (69.2 KB)

Well, I tried to open the file and it worked for me.

To see what I am talking about–just move the arrow around the closed curve. You will get, at least I do, a naked edge/s where ever the arrow is placed.

Thanks for responding…

Yeah, that looks like it’s a bit buggy to me… The “naked” edges are way within joining tolerance of each other. Running Explode/Join works to close the object. @pascal, one for the bug pile (fails in V6 as well)?


Needing to get the project on the way, and learning in the process. Attached is a file showing what will work and some thing that won’t.

So, I don’t know if this is a bug; however, all attempts to sweep a “Closed Curve failed”

See attached file…

Example Panel—Solutions—.3dm (6.7 MB)

Hi Joe - I’m not wild about rebuilding the arc-ish curve to 500 points and degree 1! Unless you need a dense polyline there for some reason. I’d spend a little time with that curve and draw it properly - I used an ArcBlend below and got it pretty much right on with a far simpler curve that has actual curvature rather then a teselated mock-curvature you get from a dense polyline, if you see what I mean.


Yeah, something is goofed up - Explode/Join on the result cleans up the nakeds but no idea yet why they show up to begin with.


Pascal, I’m not in favor of all the points either; however, I need to maintain the curve to “Offset” other lines. I sent this in a couple of weeks ago.


Please add tangent as an option in an ellipse. I would like to choose ellipse from center—and define a distance–horizontal or vertical and then be able to choose “tangent”—as I pull the ellipse out when it hits tangent to another curve—it indicates tangency—hit enter.

I am making French Top doors. I usually do this quickly with “Blend”; however, the top always ends up being too great a degree-(I think I have said that correctly) — it appears to have a flat spot on the top. >>> Which only gets larger as you offset the curve<<<. Since I have no choice to change the degree-(I would only need to do that on one end only)—my work around is to draw an ellipse—and guess at tangency to round the door tops and crown. You can only get so close.

So……the tangency function sure would speed up the work.

Hope you consider my suggestion……………………

I’ll play around with “ArcBlend” and see what I get from that.

Thanks for the responce & suggestion…

Have you tried working with BlendCrv (not Blend)? BlendCrv gives you lots of controls over the tangent conditions of the blend curve on either end as well as the “bulginess” - you can adjust to taste while in the command…


Thanks for the suggestion. As you can gather—I’m not familiar with all commands. Even though I have been using Rhino for about 7 Years—I seem to use just a small amount of it’s total package.

Thank you Mitch…