Problems with inserting a selection!!

I'm trying to write a lisp that subtracts one (or more) solids from a solid. (much like the standard ACAD command). however I'm trying to do it so that it draws back in the solids you have subtracted.
i.e I need to do lots of subtracting, but also keep the original solids I subtracted...if that makes sense???

I've used the following code to get my selection sets, but I'm not sure how I go about re-inserting the original solids (named sub) back into the model

(defun c:sub ()
(princ "\nSelect objects to be subtracted from ")
(setq subtfrom (ssget))
(princ "\nSelect solids and regions to subtract ")
(setq subt (ssget))
(command "subtract" subtfrom "" subt "")
)

Can anyone help??

TIA

M

 

Copy the objects to be subtracted prior to the subtract operation.

 

No error handling and v. basic but it will do what you want.

(defun c:subkeep ()
(princ "\nSelect solids and regions to subtract from..")
(setq obj1 (ssget))
(princ "\nSelect solids and regions to subtract..")
(setq obj2 (ssget))
(command "copy" obj2 "" "0,0" "0,0")
(command "subtract" obj1 "" obj2 "")
)


Spencer

 

make variables local as below

(defun c:subkeep (/ obj1 obj2)
(princ "\nSelect solids and regions to subtract from..")
(setq obj1 (ssget))
(princ "\nSelect solids and regions to subtract..")
(setq obj2 (ssget))
(command "copy" obj2 "" "0,0" "0,0")
(command "subtract" obj1 "" obj2 "")
)

 

Thanks Gent's

M