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@Jamesclark64 This can do the job? (vl-load-com) (defun cut@point (ss lst_pt / n ename dxf_10 rtn_ss pt_brk lst_brk lst_sort dxf_obj dxf_43 dxf_38 dxf_39 dxf_10 dxf_40 dxf_41 dxf_42 dxf_210 ltmp lst_tmp where count nwent indx) (repeat (setq n (sslength ss)) (setq ename (ssname ss (setq n (1- n))) dxf_10 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget ename))) rtn_ss (ssadd) ) (foreach el (mapcar '(lambda (x) (trans x 0 ename)) lst_pt) (setq pt_brk el lst_brk (cons el lst_brk) ) ) (setq lst_sort (mapcar '(lambda (x) (list (vlax-curve-GetDistAtPoint ename (trans x ename 0)) (list (car x) (cadr x)))) lst_brk) lst_brk (reverse (mapcar 'cadr (mapcar '(lambda (x) (assoc x lst_sort)) (vl-sort (mapcar 'car lst_sort) '<)))) dxf_obj (entget ename) ) (if (cdr (assoc 43 dxf_obj)) (setq dxf_43 (cdr (assoc 43 dxf_obj))) (setq dxf_43 0.0) ) (if (cdr (assoc 38 dxf_obj)) (setq dxf_38 (cdr (assoc 38 dxf_obj))) (setq dxf_38 0.0) ) (if (cdr (assoc 39 dxf_obj)) (setq dxf_39 (cdr (assoc 39 dxf_obj))) (setq dxf_39 0.0) ) (setq dxf_10 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) dxf_obj)) dxf_40 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 40)) dxf_obj)) dxf_41 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 41)) dxf_obj)) dxf_42 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 42)) dxf_obj)) dxf_210 (cdr (assoc 210 dxf_obj)) ) (if (not (zerop (boole 1 (cdr (assoc 70 dxf_obj)) 1))) (setq dxf_10 (append dxf_10 (list (car dxf_10))) dxf_40 (append dxf_40 (list (car dxf_40))) dxf_41 (append dxf_41 (list (car dxf_41))) dxf_42 (append dxf_42 (list (car dxf_42))) ) ) (repeat (1+ (length lst_brk)) (setq ltmp nil lst_tmp (vl-member-if '(lambda (x) (and (equal (car x) (caar lst_brk) 1E-08) (equal (cadr x) (cadar lst_brk) 1E-08))) dxf_10) where (if lst_tmp (vl-position (car lst_tmp) dxf_10) 0) ) (repeat (setq count (- (length dxf_10) where)) (setq ltmp (cons (mapcar '(lambda (x y) (cons y (nth where x))) (list dxf_10 dxf_40 dxf_41 dxf_42) (list 10 40 41 42)) ltmp)) (setq where (1+ where)) ) (entmake (append (list (cons 0 "LWPOLYLINE") (cons 100 "AcDbEntity") (assoc 67 dxf_obj) (assoc 410 dxf_obj) (assoc 8 dxf_obj) (if (assoc 62 dxf_obj) (assoc 62 dxf_obj) (cons 62 256)) (if (assoc 6 dxf_obj) (assoc 6 dxf_obj) (cons 6 "BYLAYER")) (if (assoc 370 dxf_obj) (assoc 370 dxf_obj) (cons 370 -1)) (cons 100 "AcDbPolyline") (cons 90 (length ltmp)) (cons 70 (boole 1 (cdr (assoc 70 dxf_obj)) 128)) (cons 38 dxf_38) (cons 39 dxf_39) ) (apply 'append (reverse ltmp)) (list (cons 210 dxf_210)) ) ) (repeat (1- count) (setq dxf_10 (reverse (cdr (reverse dxf_10))) dxf_40 (reverse (cdr (reverse dxf_40))) dxf_41 (reverse (cdr (reverse dxf_41))) dxf_42 (reverse (cdr (reverse dxf_42))) ) ) (setq lst_brk (cdr lst_brk) ltmp nil nwent (entlast) rtn_ss (ssadd nwent rtn_ss)) ) (setq indx (1- (sslength rtn_ss))) (repeat (sslength rtn_ss) (if (eq (boole 1 indx 1) 1) (entdel (ssname rtn_ss indx)) ) (setq indx (1- indx)) ) (entdel ename) ) ) (defun c:altern_poly ( / ss n ss_save ent dxf_ent lst_pt brk_pt) (while (not (setq ss (ssget '((0 . "LWPOLYLINE")))))) (repeat (setq n (sslength ss)) (setq ss_save (ssadd) ent (ssname ss (setq n (1- n))) ss_save (ssadd ent ss_save) dxf_ent (entget ent) lst_pt (mapcar 'cdr (vl-remove-if '(lambda (x) (/= (car x) 10)) dxf_ent)) ) (if (equal (append (car lst_pt) (list (getvar "ELEVATION"))) (vlax-curve-getendpoint ent) 1E-08) (setq lst_pt (append lst_pt (list (car lst_pt)))) ) (if (>= (length lst_pt) 3) (progn (setq brk_pt nil) (while (and lst_pt (cadddr lst_pt)) (setq brk_pt (cons (caddr lst_pt) brk_pt) lst_pt (cdddr lst_pt) brk_pt (cons (car lst_pt) brk_pt) ) ) (if (eq (boole 1 (cdr (assoc 70 dxf_ent)) 1) 1) (setq brk_pt (cdr brk_pt))) (cut@point ss_save brk_pt) ) ) ) (prin1) )

I believe any command that is built-in to AutoCAD is proprietary product and cannot be disclosed to the public. However, some built-in AutoLISP commands, for example, the Express Tools of AutoCAD, are all saved in your local computer and can be viewed anytime under your directory "C:\Program Files\Autodesk\AutoCAD 2021\Express" (assuming your CAD version is 2021). Anyways, that aside, just as the previous comment suggested, finding a point that overlaps with basically any curve is relatively easy. But finding the overlaps of two curves, even between two polylines as shown below, is not easy.

Best thing is to post a sample dwg to see what exactly you want. To find overlapping POLYLINE & POINT, or in other words find points on polyline is relatively easy

Sorry, I forgot to mention.. ATTIPE=1 will use Full Text Editor with Attributes.