How To Create a NURBS Circle?

[spinecad]

Can someone please tell me how to create a NURBS circle in AutoCAD?

 

Thank you

[ReMark]

See this thread by SEANT posted back in 2009.

 

http://www.cadtutor.net/forum/showthread.php?32338-Splined-Circles

[Stefan BMR]

Follow these steps:

1) Chose how many segments you want and draw a regular polygon (3 in my sample).

Keep a segment of it (in my sample, is a triangle p1 p2 p3)

Draw a spline thru p1 p2 p3, in this order. Make sure you chose CV spline and 2nd degree.

2) In properties dialog, set weight just for the second control point of spline to cos(a). (see img. #2 for angle a)

3) Copy and rotate spline to complete a circle. Run SPLINEDIT command and join all spline segments.

 

At bottom of image you can see circles created from 3, 4, 5 and 6 segments.