RE: [rp-ml] Circles in Rhino

From: Jonathan Chertok <>
Date: Sun Jun 20 2004 - 20:02:23 EEST


This sounds like one of those urban legends...nevertheless like the last
poster I'm curious about how one would measure this.

My understanding is that Rhino V3 reorganized some of their object types.
Objects supported in Rhino V3 are:

NURBS Surface
Polygon Mesh
Text Block
Point Cloud (new)

New Curve Types are:

Arc/Circle (new)
Polyline (new)
Line (new)
Ellipse (new)

New Surface Types are:

Plane (new)
Surface of Revolution (new)
Sum Surface (new)


Somehow I understand circles and some "primitives" in Rhino have a kind of
dedicated (implicit or explicit...) definition to them.

I'll hazard a guess and say that somewhere along the line someone took the
information they understood about NURBS Weights being able to define Conics
(circles, ellipses, parabolas, hyberbolas) and mangled the information as
they passed it down the line - to whoever you heard it from.


That said, it would also be interesting - I suppose - to know if an
arc/circle object in Rhino gives a different "result" (again what does one
use to measure this) than one that is created using NURBS Weights.

Bathsheba's advice to post to the Rhino NG is the best. They'll put a
programmer on the list to bust the myth, if necessary. But perhaps Caleb is
out there and he knows something about the issue.



Universal Joint: Buildings + Digital Design

Jonathan Chertok. Principal
Austin, Texas [512] 407 9628 [ coming soon ]

----Original Message Follows----
Subject: [rp-ml] Circles in Rhino
Date: Sat, 19 Jun 2004 13:56:15 EDT

We have heard that Rhino does not give you a true circle when you are
designing. Instead, a circle will come out as an ellipse.
Is this true?


FREE pop-up blocking with the new MSN Toolbar get it now!
Received on Sun Jun 20 19:22:49 2004

This archive was generated by hypermail 2.1.8 : Tue Jan 12 2010 - 19:37:11 EET