# drwg 3-D tubes w/ radii using extrude & pathcurve

Now I have 2002, and am not sure if this is possible yet. I tried it with R13, 14, if not others.
Trying to draw (commonly manufactured) tubes (hollow) like an exhaust
system.
Something will not compute. Maybe something about multiple planes. Can't remember if at the pedit stage, or extrude, or how to work around.
I'm trying: Drawing contiguous straight lines joined at ends in multiple planes, then adding radii, join them all together with Pedit, to use as a pathcurve. Then drawing circle(s) perpendicular at the end, and polyline as a pathcurve to extrude.
I'd love to get to the bottom of this.
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At least as far up as 2000, it won't work, i.e., extrude won't work along a 3D polyline. You have to draw individual circles at one end of each line or arc and extrude those. Which in turn requires a lot of manipulation of the UCS.
You can re-use the circle for an adjacent line and arc if you <setvar> <cr> <delobj> <cr> 0 <cr>, which causes AutoCAD to not delete the circle after using it. I usually run with delobj off, because going back and retracing your steps (to correct a mistake) is easier if the primitives are retained.
-Mike-
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Mike Halloran wrote:

You can extrude a circle along a polyline, though as you mention, not a 3D polyline. Draw one polyline per plane, should save a couple of steps.
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TomD wrote:

Can't you extrude along multiple polylines in different planes as long as the plane is parallel to the UCS?
Doug T
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There is a TUBEX.LSP available on the Net which extrudes a circle along of lines drawn in 3D space. Lines must not be polylines, that's a condition of this routine. I use it (the lisp) for drawing different pipes in 3D quite often. Let me know if you have difficulties finding the lisp on the Net. I will E-mail you one.
Regards,
Doug T wrote:

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<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <font face="Courier New,Courier"><font size=-1>There is a TUBEX.LSP available on the Net which extrudes a circle along of lines drawn in 3D space. Lines must not be polylines, that's a condition of this routine. I use it (the lisp) for drawing different pipes in 3D quite often. Let me know if you have difficulties finding the lisp on the Net. I will E-mail you one.</font></font> <p><font face="Courier New,Courier"><font size=-1>Regards,</font></font> <p><font face="Courier New,Courier"><font size=-1>Igor.</font></font> <br>--
<br>&nbsp; <br>&nbsp; <p>Doug T wrote: <blockquote TYPE=CITE>TomD wrote: <br>> <br>> Mike Halloran wrote: <br>> > At least as far up as 2000, it won't work, i.e., extrude won't work along a 3D <br>> > polyline.&nbsp; You have to draw individual circles at one end of each line or arc <br>> > and extrude those.&nbsp;&nbsp; Which in turn requires a lot of manipulation of the UCS. <br>> <br>> You can extrude a circle along a polyline, though as you mention, not a <br>> 3D polyline.&nbsp; Draw one polyline per plane, should save a couple of steps. <p>Can't you extrude along multiple polylines in different planes as long as the <br>plane is parallel to the UCS? <p>Doug T</blockquote>
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Doug T wrote:

I better clarify that I'm no 3D wiz before continuing. I remember extruding a closed shape (polyline) along a polyline. So long as the object being extruded was perpendicular to the path, and the path was on one plane, I didn't have any trouble with it.
Hopefully that's adding to the conversation. ;)
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