Flatten cone

I need to draw an offset cone in 3D, then flatten it out to get a pattern which I can then dimension for ultimate fabrication in fibreglass. Can I do this in Autocad 2000, and if so how? Thanks.

David

What do you mean by "offset" cone? Is the base not in line with the apex?

I need to draw an offset cone in 3D, then flatten it out to get a pattern which I can then dimension for ultimate fabrication in fibreglass. Can I do this in Autocad 2000, and if so how? Thanks.

 

David

You can do that in AutoCAD but be prepared, AutoCAD will not do it for you.

Don't know what you mean by "offset" cone neither.?

If you intend to draw an eccentric cone and then unfolding it, so I recommend

http://www.black-cad.de

Regards

Jochen

This will help you draw the cone.

http://cadtutor.net/forum/viewtopic.php?t=4941&highlight=econe

If you can create the cone using a rulesurf, here is an AutoLisp routine that will make the flat pattern. -David

http://www.davidbethel.com/lisp/pattern.lsp

Thanks David, I'll give it a go and let you know how I get on. And thanks to Aled and Paul

David

I sometimes have to make fabric patterns for truncated cones. I made up this "how to", so that I didn't have to remember how to do it each time...or so that others could do it in my absence.

Sorry, that image is a little big.

sdbell,

Here's a lisp program that you can load, it takes your keyboard input of dimensions and steal thickness. Then draws it in the flat for the cutter & roller.

; Convert angle in degrees to radians
       (defun dtr (a)
       (* pi(/ a 180.0))
       )
; Configs Cones & Draws it in the flat
(defun c:coneflat ()
 (setvar "lunits" 2)
 (setvar "luprec" 2)
 (SETQ PCK1 (Getpoint "\nPick Location of Cone: "))
 (SETQ LD (GETREAL "\nEnter Large ID: "))
 (SETQ SD (GETREAL "\nEnter Small ID: "))
 (SETQ H (GETREAL "\nEnter Mean Height of Cone: "))
 (SETQ THK (GETREAL "\nEnter Thickness: "))
 (setq D (+ LD THK))
 (setq D1 (+ SD THK))
 (setq 2b (- D D1))
 (setq b (/ 2b 2))
 (setq sqh (* h h))
 (setq sqb (* b b))
 (setq sqrc (+ sqb sqh))
 (setq c (sqrt sqrc))
 (setq r (/ D 2))
 (setq R2 (/ (* c r) b))
 (setq e (- R2 c))
 (setq deg (* (/ r R2) 360))
 (setq lim (* R2 2))
 (setq limi (+ lim 20))
 (command "circle" PCK1 e)
 (command "circle" PCK1 R2)
 (setq Ptt2 (polar PCK1 (dtr 0.0) R2))
 (setq Ptt3 (polar PCK1 (dtr 0.0) e))
 (command "line" Ptt2 Ptt3 "")
 (command "line" Ptt2 Ptt3 "")
 (command "zoom" "c" PCK1 limi "")
 (command "rotate" "l" "" PCK1 deg)
 (setq Ptt4 (polar PCK1 (dtr 358.0) (+ r2 10.0)))
 (command "trim" "" "f" PCK1 Ptt4 "" "") 
)