boundary surfaces prior to thickening are a result of several curve operations (pulling, pinching, splitting, joining again, etc.) - areas with super tight control points were my initial suspicion - once I simplify all curves, point duplication is resolved, yet I continue to get a remnant of the bug still:
I didn’t look at the model at all, just pointing out a common issue. Previews can look weird at less than “High Quality”. OK, looking at the model now… Looks pretty good to me. I baked the output and looked VERY CAREFULLY to find one section that exhibits anomalous behavior like you describe. I don’t know what’s causing that as I now have GH disabled completely. Your offset distance (0.01 and -0.01) is very small, don’t know if that’s a factor?
Baking the curves alone, before and after Simplify, shows them to have MANY control points and a few discontinuities that happen to be near these anomalies.
The problem appears to diminish (vanish?) if you Rebuild the curve using a fraction of the original control points (~1/3rd), but then you don’t have the same “ribs”.
I believe it’s a Rhino’s Render mesh quality problem.
Switch to “Custom” quality fr “Jagged and faster” in rhino option would help to resolve the problem.
(Beware, it’s slow.)
@HS_Kim has the answer but oddly, the problem mostly vanishes even when you push the slider in my model to ‘1.0’, using the same number of control points as the original curves and looking very similar. Good luck. What are these “ribs”, anyway?
In Rhino 6, I’m seeing a recurring jagged edge condition on one part in particular. I believe the jaggies appear when any parameter affecting this shape (the blue ring in the video below) are modified. If you close and reopen the file, the problem disappears. Even more mysteriously, they go away like magic when the ‘SDiff’ component is copy/pasted!??
I’d REALLY prefer to spend more time on my own projects and WAY LESS time dealing with buggy code and reporting anomalies like this. Rhino 6 is a head banger. Still seriously flawed a couple of years after release?
By the way, I tried the usual tricks, setting Render Mesh Quality to “Smooth and slower”, etc.
Another mysterious anomaly with geometry display. The top corners of the geometry on the right have gaps after Brep Join that aren’t visible in the separate pieces on the left. This is wrong.
Changing ‘View | Display Options | Mesh (Render mesh quality)’ to ‘Smooth and slower’ fixes the issue BUT NOT IMMEDIATELY! After changing that setting, the Join component must be re-triggered before the problem goes away. Simply reconnecting the wire between the Brep param and Join will force a re-render using the modified ‘Render mesh quality’.
looking into this
Rhino 6 is a head banger. Still seriously flawed a couple of years after release? 
