undesired bending effect when twistintg on sw2005 flex command

Hi everyone,
i'm trying to twist 270 degrees a box which is 22*22*140 mm using the
flex feature. the resultant object has an undesired bending in the
midle while the top and bottom stays in position along twist axis.
doing the same action on Rhino gives me a fine twist, but i need the
object as sw2005 feature for future editing.
does anyone of you guys encounter this strangeness? and if so, is
there a way to fix it in solidworks?

Thanks,
Gil Alsberg

 

Gil,

Try this:
1. Sketch a 22mm X 22mm box
2. New sketch circle from center of box to one corner
3. using the circle, create a helix using Height and Revolution, with rev
being .75 (270 degrees) 140mm long
4. Sweep the box along the helix.

Is this what you're after?

Muggs

 

Here's a Jpeg of what I got:

http://home.comcast.net/~muggs828/solidworks/box_sweep.jpg

Muggs