Topic: help extruding in a 3d path

[nekonihonjin]

Hello everyone.

I'm using the "Mextrude" lisp made by gile
It's been very usefull with lwpolilnes (in fact is an excelent routine)

I have a problem when using the "3dPolyFillet" made by Gilles Chanteau

if I extrude a profile in a previously 3dfilleted 3dpolylne it ends up a little twisted and I need it to continue horizontal.

I'll attach a file for detalis. and the lisp routines that I mentioned above.

[ribarm]

Maybe you can try this posted here :

http://www.theswamp.org/index.php?topic=49959.0

But I suppose it'll be also quirky, but test it, you'll never know...

[nekonihonjin]

Maybe you can try this posted here :

http://www.theswamp.org/index.php?topic=49959.0

But I suppose it'll be also quirky, but test it, you'll never know...

I was testing with your modifications to this routine and I realized that the problem is the mextrude.lsp
Even when the 3dpolyline has not been filleted yet, it still result a twisted extrusion. Guile worked with circles to create a pipe, so I guess he did not notice this behaviour.

[gile]

Hi,

Yes I noticed this behaviour which is not due to the mextrude LISP but to the way the AutoCAD extrusion works with non planar paths (the native _SWEEP command gives the same result).
To to what you want, you have to use the _LOFT command.

[nekonihonjin]

Hi,

Yes I noticed this behaviour which is not due to the mextrude LISP but to the way the AutoCAD extrusion works with non planar paths (the native _SWEEP command gives the same result).
To to what you want, you have to use the _LOFT command.

loft joins 2 or more profiles to make the solid, I don't know how to use it to extrude it along the 3dpolyline.

[gile]

Hi,

This is a quite old LISP which dispach a profile (section) along a path.
The profile must be a block containing a single planar entity oriented so that its X axis will be aligned to the path tangents (see the example in the attached dwg file.

A little video.

[nekonihonjin]

Hi,

This is a quite old LISP which dispach a profile (section) along a path.
The profile must be a block containing a single planar entity oriented so that its X axis will be aligned to the path tangents (see the example in the attached dwg file.

A little video.

This is perfect, thank you again.

[ChrisCarlson]

Try converting the polyline to a spline

Code - Auto/Visual Lisp: [Select]

1. (defun C:PL2SPL ( / ss i)
2.         (if
3.                 (setq ss (ssget '((0 . "*POLYLINE"))))
4.                 (repeat (setq i (sslength ss))
5.                         (make_spline
6.                                 (pl_list (ssname ss (setq i (1- i))))
7.                         )
8.                 )
9.         )
10. (princ)
11. )
12. (defun pl_list (e / r i j lg)
13.         (setq lg (* 0.05 (vlax-curve-getdistatparam e (vlax-curve-getendparam e))))
14.         (repeat (setq i (1+ (fix (vlax-curve-getEndParam e))))
15.                 (setq r (cons (cons 11 (vlax-curve-GetPointAtParam e (setq i (1- i)))) r))
16.                 (if
17.                         (and
18.                                 (> i 0)
19.                                 (> (- (vlax-curve-getdistatparam e i) (vlax-curve-getdistatparam e (1- i))) lg)
20.                         )
21.                         (repeat (setq j 3)
22.                         (setq r (cons (cons 11 (vlax-curve-GetPointAtParam e (+ (1- i) (* 0.25 j)))) r) j (1- j))
23.                         )
24.                 )
25.         )
26.         r
27. )
28. (defun make_spline (l)
29.         (entmake
30.                 (append
31.                         (list
32.                                 '(0 . "SPLINE")
33.                                 '(100 . "AcDbEntity")
34.                                 '(100 . "AcDbSpline")
35.                                 '(70 . 1)
36.                                 '(71 . 3)
37.                                 (cons 74 (length l))
38.                                 '(44 . 1.0e-005)
39.                         )
40.                         l
41.                 )
42.         )
43. )

https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/3d-polyline-to-polyline-to-spline-with-max-1mm-tolerance/m-p/4446325#M315222