Renegade lines in some Display modes

Is there a fix for this?In all line-drawn modes (this is Hidden) there are lines showing up in the image immediately below where there aren’t any edges in reality on these window casings (created with Sweep1). This creates line drawings which are misleading about the details of the interior I’m drawing up. (please also see the other views below):

The raytraced display mode view immediately below shows where the actual edges are in these (Sweep1’d) window casings:

The extraneous lines aren’t isocurves (this wireframe shows where all the isocurves are):

hard to say the problem without the file.

MouldingEdges.3dm (796.0 KB)

those lines are surface edges, I would recommend to use few extrusions instead of sweep 1

also, the sections curves have some issues.

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to harvest simple non trimmed surfaces you can use RailRevolve on a quadrangular (thats just to get all sides equal, otherwise the shorter sides get stretched). after that use SolidPtOn and move it into size.

i wished RailRevolve would have an option to keep the profile in tact on rails with 2 or more “radii”. @pascal would that be a valid wish?

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Thanks Diego

Do you mean the command in rhino has issues, or the curves from which the moulding was swept?

hmm- it is not clear to me right now why this happens in RailRevolve - I need to poke at it some more.

OK, I see, … yeah, I would say this is probably not an easy ‘fix’ for how RR works - I don’t know how it would enforce the 45 degree miter - as it is the miter takes the aspect ratio of the path rectangle…

@djhg - MergeAllFaces on your sweep result may do what you need to clean up the display in this case…


It doesn’t. But if it works for you on the project uploaded above, there’s something wrong with my Rhinoceros.

Hello - no, the faces are not planar, it won’t work. Can you post the input curves?

Staring from your edges - i.e. making new curves - and making a new sweep, comes out noticeably cleaner than the one you posted, so I’m curious as to how you got there. It still has the edges you do not like, however, that is part of the process. For what it is worth, I make this type of shape by Loft of multiple section curves, the ones at the corners being sheared 45 deg.


yes that sound logic, i was actually just “abusing” RailRevolve for such matters because it produces better results. in that case my wish would be to have sweep deliver simple non trimmed surfaces instead.

I swept the below block around a pline.

MouldingProfile.3dm (104.6 KB)

Hmmm - ok - I cannot get what you have in the file you posted, which is a mis-match between those corner bits and the long straights:


A new sweep gets me this:


which is more what I’d expect.

At any rate, none of that eliminates the edges that are irking you, I’d use Loft as outlined above.


Yes. Something about the initial moulding isn’t right.

I have just tried that again. This time it worked fine. In fact it worked better than yours did. I am going to trace back to the rail I used for the initial sweep to see if it was planar or not.

I have gone back to original rail curve from which this moulding was swept. There must be something wrong with it, because it gives those persistent edges. Maybe it can be examined to determine what.MouldingEdgesandCurves.3dm (431.3 KB)

This looks correct - I was commenting on the difference between the surfaces at the miter - I don’t see how that got there in your original…



Of the attempts to troubleshoot this, the below is the only one that’ll display as required. I got it by railrevolving and then trimming. (What’s correct about it is the absence of ‘false’ edges on either side of the mitre.) I also got it by trimming the rectangle and sweep1. (there’s something that’s sometimes causing errors with that, though. both your example and my recent upload introduce that.)

And in the original the top is different from the upright.

I would remake the entire window casing, but rather than loft my choice would be to extract the profile curve from the bottom left face and extrude a solid up beyond the top. Then create a diagonal line through the top left corner and use it to mirror the new solid to get a top which matches the upright. Mirror the upright and diagonal line about the centre of the window to get a matching right upright. Then use the two diagonals to trim the three solids.


Resulting in corners like this:


Hello - as far as I can see Sweep1 is doing exactly what it is supposed to do. I understand you do not like that it is split into multiple faces, but that is part of the deal - there is no guarantee that surface edges will end up where piece-of-wood edges are. As I mentioned above, one way to get the geometry to ‘match’ the wood is to shear the profiles at the corners and Loft


Thanks, but sometimes it gives the desired result with almost identical geometries, sometimes not?

It looks like sweeping to the inside gets the result you are after - offset the sweep rail by the depth of the profile and see how that looks.