WIP 9dot0dot26097dot12305

Rhino
1

unable to create a circle tangent to three curves; see attached file. where do I find ellipse curve creation in WIP 9.0…… ??

Art

Weber fastener fairing.3dm (87.6 KB)

2

forgot to add “trial and error” attempt

Art

trial and error approximation
trial and error approximation1754×1102 98.2 KB

3

Hi @artesmith,

Your circle tangential to three curves isn’t giving the result you expect because the three curves are not in the same plane. Make them so and you’ll get a circle in the plane.

image
image1259×746 10.2 KB

I don’t believe there is any tool for directly creating an elliptical arc - you either create an ellipse and trim it, or a circular arc and scale it. Incidentally there is a new ‘fit to points’ option for the ellipse command, in the WIP only, but you need to run it with the hyphen option, -ellipse, to see that as it hasn’t been added to menus or toolbars.

HTH
Jeremy

4

Jeremy-

thanks!! how do I determine/verify curves are co-planar? clearly the construction was undertaken believing the curves were all in the same plane…..

Art

5

Well, I’m on my laptop and suspected they weren’t co-planar from the command behaviour so I checked in the front view. But on my desktop with a large screen, I keep the Boxedit panel open all the time, so I can immediately see if a selection of several curves has height when it shouldn’t. If the plane of the curves isn’t parallel to the world planes you need to set a cplane and use the cplane option in Boxedit for this to work, of course.

6

This script might help:

CheckCrvsCoPlanarity.py (1006 Bytes)

To make them coplanar, a variety of methods, SetPt in Rhino is one of them if the curves are supposed to be parallel to one of the principal planes.

7

thanks guys!!

Art

8

must be thick. I’ve rebuilt the involved geometry and used “Setpt” to doubly make sure everything is co-planar; and “circle tangent to three curves” will have nothing to do with me……………… the updated file is below; haven’t tried the “-ellipse” command yet

Art

Weber fastener fairing.3dm (85.6 KB)

9

No problem here…

image
image1561×1168 13.9 KB

Circle>Tangent, pick curves1, 2, 3…

Weber fastener fairing-1.3dm (106.4 KB)

10

The only thing that I can think of which would give you trouble is to select the curves in the wrong places - you have to choose them in the segment where you want the tangent to lie. So pick them in the white sections, not the purple, here:

image
image1047×924 6.39 KB

HTH
Jeremy

11

What I am noticing is that the Cen osnap seems to be getting in the way if you have it activated… I’m not sure why it would be if you are trying to do tangents… Seems like it should be “tuned up” maybe. In any case Cen has always been too strong IMO, I have it turned off almost all the time and generally only use it as a one-shot.

12

thanks guys!! operator was attempting to select in the wrong spots…….

Art