Drafting Techniques

Drafting Techniques

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1 Posts
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Registered: ‎06-21-2012
Post 1 of 4

Rectangle to round

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06-21-2012 07:00 AM

I am running AutoCAD 2004 and I need to create a piece of duct work that transitions from a 14" x 16.875" rectangle to a 24" diameter. The length is 18". I am not sure how to create this so that I can cut 4 equal parts to be welded together to form the finished product.  Thanks

184 Posts
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Registered: ‎06-09-2007
Post 2 of 4

Re: Rectangle to round

06-28-2012 10:29 PM in reply to: ONELWIL

In 3D? If so, draw a rectange and cirlcle centered within to your dinensions. Draw a line to throgh the middle and trim both on one side, then mirror them. Move them so they'e 18" apart. Set SURFTABF1 and SUFTAB2  for desired smoothness.then use Rulesurf for each side.

(If rou try Rulesurf with just the circle and rectange the mesh converges in the middle.)


Valued Mentor
900 Posts
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Registered: ‎12-26-2005
Post 3 of 4

Re: Rectangle to round

01-09-2013 06:32 AM in reply to: doben

You can find code for Doben's method in the autolisp world, and maybe VBA.




If the resultant of Rulesurf is a hourglass, then the order of vertices do not match; reverse the circle or something.

16 Posts
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Registered: ‎08-15-2012
Post 4 of 4

Re: Rectangle to round

01-25-2013 01:32 PM in reply to: ONELWIL

If you were going from a 14"X14" to the round, then you could probably have 4 equal pieces.  But since it is rectangular, 2 sides will be a little longer and make it harder to create 4 equal pieces.  I drew it to your specs (plus added a 1" extension on either end for my testing purposes).  But as you can see from the drawing, it would be hard to get the 4 equal pieces.

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