With @quadhurst I’m trying to draw a tramway wiring insulator, which looks like this:
But we can’t get it quite right. This is close, but not perfect.
The overall dimensions are 4 3/8" H x 2 1/4" square.
I’ve used this path for FollowMe (highlighted in blue below) with the arc radii as shown:
All the straight edges are vertical.
Instead of generating a surface with a large radius of 1 1/8" (1.125"), it is 1.147"R. The generated edges don’t quite match the path and are not (quite) a circular arc.
The same is true at the ‘bottom’ of the FollowMe surface - it doesn’t match the half circle of 5/16" radius in the path.
Why?
I have also tried the path with half a circle rotated by half a segment, instead of a half-circle arc.
Like this:
It made no difference to the radius generated by FollowMe.
Any suggestions for how to draw this shape accurately? I have Curviloft if that might help.
Here’s the file in v2017.
Line insulator.skp (150.9 KB)
Am I wrong in my expectation of what FollowMe would do? Seems so.
LATER
Well, Curviloft may be the answer. Here’s a quarter of the insulator outer surface using Curviloft.
LATER STILL
Finished model with rounded edge - FollowMe half circle on a scaled up copy.
Line insulator 2 JWM v7.skp (303.6 KB)
But I’d still like to know how to draw this shape with native tools only.