As you can see, these LISP routines are very helpful.
With this one you can pick an object (except LWPOLYLINES) and specify a starting point and then tell it how far along that object you would like to place a node. After the initial node is placed, it measures from the previous node.
In the example animated picture:
- TRACEPOLYLINE <enter> to start
- Select object (Note that it works with polylines and splines as seen in the picture)
- specify starting point
- Specify distance of 10 feet <enter>
- Specify distance of 5 feet <enter>
etc…
(The picture is so large that you may need to click it so that it opens up in a separate window in order for it to load.)
Code criginally posted @ http://www.cadtutor.net by ASMI
(defun c:tracepolyline(/ *error* cCurve curPt dPar dPt enPt fPar fPt maxLen obType oldDis oldOsn posDir rClose sFlag stPt sumDis swMod undoLst vClose whatDo) (vl-load-com) (defun asmi_GetActiveSpace(/ actDoc) (if (= 1(vla-get-ActiveSpace (setq actDoc (vla-get-ActiveDocument (vlax-get-acad-object) ); end vla-get ActiveSpace ); end setq ); end vla-get-ActiveDocument ); end = (vla-get-ModelSpace actDoc) (vla-get-PaperSpace actDoc) ); end if ); end of asmi_GetActiveSpace (defun RestorePointStyle() (if (and xdiv:oldPm xdiv:oldPs) (progn (initget "Yes No") (setq swMod (getkword "\nRestore point style? [Yes/No] <No>: ")) (if(null swMod)(setq swMod "No")) (if (= swMod "Yes") (progn (princ "\nPlease wait... \n") (setvar "PDMODE" xdiv:oldPm) (setvar "PDSIZE" xdiv:oldPs) ); end progn ); end if ); end progn ); end if (princ) ); end of RestorePointStyle (defun AddPointOrInsert(Mode Block Scale) (vla-AddPoint (asmi_GetActiveSpace) (vlax-3d-point curPt)) ); end of AddPointOrInsert (defun AddPointOrInsert(Mode Block Scale / outObj) (setq undoLst (append (list (list (setq outObj (vla-AddPoint (asmi_GetActiveSpace) (vlax-3d-point curPt))); end setq curPt xdiv:curDis ); end list ); end list undoLst); end append ); end setq outObj ); end of AddPointOrInsert (defun *error*(msg) (if cCurve (progn (vla-Highlight cCurve :vlax-false) (setvar "OSMODE" oldOsn) ); end progn ); end if (princ "\n*Cancel*") (princ) ); end of *error* (if (member (setq xdiv:oldPm(getvar "PDMODE")) '(0 1) ); end member (progn (setq xdiv:oldPs(getvar "PDSIZE")) (initget "Yes No") (setq swMod (getkword "\nChange points style to good visible? [Yes/No] <Yes>: ")) (if(null swMod)(setq swMod "Yes")) (if (= swMod "Yes") (progn (princ "\nPlease wait... \n") (setvar "PDMODE" 35) (setvar "PDSIZE" -2) ); end progn ); end if ); end progn ); end if (setq oldOsn (getvar "OSMODE")); end setq (if (not xdiv:curDis) (setq xdiv:curDis 1.0 xdiv:oldDis 1.0); end setq ); end if (if (setq cCurve (entsel "\nSelect curve > ")); end setq (progn (setq cCurve (vlax-ename->vla-object (car cCurve))); end setq (if (member (setq obType (vla-get-ObjectName cCurve)) '("AcDbLine" "AcDbPolyline" "AcDb3dPolyline" "AcDbSpline" "AcDbArc" "AcDbCircle" "AcDbEllipse") ); end member (progn (vla-Highlight cCurve :vlax-true) (setvar "OSMODE" 3071) (setq stPt (vlax-curve-GetStartPoint cCurve) enPt (vlax-curve-GetEndPoint cCurve) fPt (getpoint "\nPick start markup point at curve > ") ); end setq (if fPt (setq fPt(trans fPt 1 0) curPt(vla-AddPoint (asmi_GetActiveSpace) (vlax-3d-point fpt)); end vla-AddPoint undoLst (list (list curPt 0.0 0.0)); end list ); end setq ); end if (if (and fPt (setq fPar (vlax-curve-GetParamAtPoint cCurve fPt)) ); end and (progn (if (and (not(equal fPt stPt 0.0001)) (not(equal fPt enPt 0.0001)) ); end or (progn (setq dPt (getpoint fPt "\nPick point at curve to specify markup direction > ")) (if dPt (setq dPt(trans dPt 1 0))); end if (if (and dPt (setq dPar (vlax-curve-GetParamAtPoint cCurve dPt)) ); end and (progn ); end progn (princ "\nEmpty input or point not at curve! ") ); end if ); end progn ); end if ); end progn (princ "\nEmpty input or point not at curve! ") ); end if ); end progn (princ "\nInvalid object type! ") ); end if (setq maxLen (- (vlax-curve-GetDistAtPoint cCurve enPt) (vlax-curve-GetDistAtPoint cCurve stPt) ); end - rClose (vlax-curve-IsClosed cCurve) ); end setq (if(equal fPt stPt 0.0001) (setq vClose T) ); end if (if (or (equal fPt stPt 0.0001) (and dPar (> dPar fPar) ); end and ); end or (setq posDir T sumDis (vlax-curve-GetDistAtPoint cCurve fPt) ); end setq (setq sumDis (- maxLen (- maxLen (vlax-curve-GetDistAtPoint cCurve fPt))) ); end setq ); end if (while(not sFlag) (setq whatDo (getstring (strcat "\nSpecify distance or [Undo/Quit] <" (if xdiv:curDis(rtos xdiv:curDis) "not defined") ">: "); end strcat ); end getstring ); end setq (cond ((or (= 'REAL(type(distof whatDo))) (= "" whatDo) ); end or (if(= "" whatDo) (setq xdiv:curDis xdiv:oldDis) (setq xdiv:curDis(distof whatDo)) ); end if (setq xdiv:oldDis xdiv:curDis); end setq (cond (posDir (setq sumDis (+ sumDis xdiv:curDis) curPt (vlax-curve-GetPointAtDist cCurve sumDis) ); end setq (if curPt (AddPointOrInsert nil nil nil) (princ "\n>>> End of line <<< ") ); end if ); end condition # 1 ((not posDir) (setq sumDis (- sumDis xdiv:curDis) curPt (vlax-curve-GetPointAtDist cCurve sumDis) ); end setq (if curPt (AddPointOrInsert nil nil nil) (princ "\n>>> End of line <<< ") ); end if ); end condition # 1 ); end cond ); end condition #1 ((=(strcase whatDo) "Q") (if (= 1(length undoLst)) (vla-Delete(caar undoLst)) ); end if (RestorePointStyle) (if cCurve (progn (vla-Highlight cCurve :vlax-false) (setvar "OSMODE" oldOsn) ); end progn ); end if (setq sFlag T) ) ((=(strcase whatDo) "U") (if (and undoLst (/= 1(length undoLst)) ); end and (progn (vla-Delete(caar undoLst)) (setq undoLst(cdr undoLst) curPt(cadar undoLst) sumDis(- sumDis (last (car undoLst))) ); end setq ); end progn (princ "\n>>> Nothing to undo <<< ") ); end if ) ); end cond ); end while ); end progn (princ "\nEmpty selection! ") ); end if (princ) ); end of c:xdiv
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