I created this ring by sweeping a profile around a circular rail; the result is split into 8 segments that I suppose correspond to the 8 curve points of the rail. When filleting/chamfering a hole that is near one of the splits between surfaces, the trim fails and leaves naked edges; however, if I do it exactly in the middle of the split, the trim succeeds.
How can I control the number of splits on the resulting polysurface of a sweep?
How can I fillet/chamfer an edge that crosses the split where to surfaces join?
If the fillet/chamfer command is not supported, how should I build the polysurface so it has less edges or how should I achieve the intended result with another command?
How did you create the curve you used for the rail? Circle command? Or something else. If rail is a polycurve then the result of sweeping along it will be a polysurface with internal edges.
I created a similar shape in two ways. Neither has the āsegmentsā. One was using RailRevolve. The other was using Sweep1 with a rail created by the Circle command. RingRevolveDC01.3dm (2.3 MB)
Both results have seams as do all closed curves, polyurves, surfaces and polysurfaces in Rhino. The location of the seam can be adjusted using CrvSeam and SrfSeam.
To adjust the location of a seam of a curve use CrvSeam.
To adjust the location of a seam in a polysurface youāll need to either Explode the polysurface, adjust the seam location(s), and Join the surfaces back into the polysurface. Or ExtractSrf a single surface, adjust the seam location of the extracted surface, and then Join the surfaces back into a single polysurface.
Thank you. I built the rail with the circle command and sweep 1. I compared with yours and was able to get a polysurface with only one seam by enabling āRefit railā otherwise it splits it in four segments.
I just realized the text is swapped in the last image. The left polysurface, with only one seam when looking from the side, is the one with āRefit railā enabled.
Why should I avoid doing it by refitting the rail? Is it because refitting is like rebuilding the curve within a certain tolerance, and it will technically not be a perfect circle, unlike the one from the circle command?
Using the .3dm from @davidcockey I noticed that the only difference was the position of the rail seam. When I place it on the inside, the resulting polysurface is split into four segments, but when placed elsewhere, it only has one lateral edge for the seam. And this time I did not refit the rail.
If the circle rail is a perfect circle, then itās not needed. Instead, you can simply use the basic āRevolveā tool (not āRail revolveā) to create the most accurate and simple circle possible. Having a single surface like that also helps with an eventual use of the āUnroll surfaceā tool, because the unrolled surface will be clean and single, too.
However, if you aim to work with single-span degree 5 surfaces, you can revolve the profile curve to 90 degrees only, then explode the resulting quarter profile (90-degree arc profile) and convert the surfaces to degree 5. If done right, they should be still true arcs while maintaining a degree 5, which is necessary for some more complex surfacing (such like rings etc) where the default circle with degree 2 may lead to some issues (for example, āBlend surfaceā exhibits a nasty bug with degree 1 or degree 2 surfaces).
So, there are two recommendations depending on your usage case:
If you aim for a true and simple output, with a possible unrolling to a flat version, then use āRevolveā.
If you aim for a single-span model, especially if you need to match other surfaces to the ring, then use 4 pieces of 90-degree arc profiles that you explode and conver5 to degree 5. Alternatively, you can split the circle into 4 arcs and convert each arc to degree 5. It should preserve its perfect structure afterwards.
For projects where the circle already exist, but you want to use āRevolveā instead, you can also use the following macro. It extracts the centerline of circles and arcs, so that they could be used as an axis for the āRevolveā command. You can also see a tutorial video in the link below.
Axis from arcs and circles ! _CPlane _Object _Pause _ProjectOsnap _Toggle Enter _Pause _Line _Vertical 0 _BothSides _Pause _Pause _Cplane _Undo _ProjectOsnap _Toggle Enter
