Help needed: creating complex LISP

[jeroen.vanloffelt736520]

Hi,

I want to create a LISP that does following actions:

1. You have a closed polyline on layer "XXX"
2. The original polyline should be placed on a frozen layer "D_XXX" and a duplicate of the original polyline should be made on layer "N_XXX"
3. The polyline on layer "N_XXX" should be trimmed between two selected points
4. A new polyline should be drawn on layer "A_XXX" and should be duplicated
5. One of the duplicates should be joined with the remaining part of the polyline on "N_XXX".
6. The end result should be: the original polyline on layer "D_XXX", the modified part of the polyline on layer "A_XXX" and the new version of the polyline on layer "N_XXX"

My question is: how should I get started with this. I've allready made some simple LISP's but this is way beyond. Any help is appreciated!

The attached DWG shows you what the LISP needs to do.

[michel.t]

You know lisp at all ? What about the selected point ? What about the new polyline to be drawn ?

[BIG-AL]

An easy way to copy an object example

(setq obj (entget (car (entsel))))
(entmake obj)
or even shorter
(entmake (entget (car (entsel))))