3D, Align by picking faces

[Grrr]

Hi guys,

Today I was working on one of my several ideas, which is aligning a selection set, by picking faces:

1.Select objects to align (SS)

2.Pick Source Face

3.Pick Destination Face

(working in 3D)

 

Needless to say that trying to get the dxf data from a 3D solid object - displays something nightmarish.

So you can see the idea I've got:

; Pick 3D Object's face
; Attempt to align objects by picking faces:

; 1.Select objects to align (SS)
; 2.Pick Source Face
; 3.Pick Destination Face
; 4.The SS is aligned, where the Source Face and Destination Face share the same plane, and their centroids are matched

;      *******************x <- mx
;      *                  *
;      *                  *
;      *        x <-cenx  *
;      *                  *
;      *                  *
; mn-> x*******************
;
; Points mn, mx and cenx are collinear!

; Grrr
; Credits to: Lee Mac

(defun C:test ( / SS msg continiue pt1 bpoly-ent1 bpoly-elist1 vla-bpoly1 mn1 mx1 box1 bpolys-cen1 pt2 bpoly-ent2 bpoly-elist2 vla-bpoly2 mn2 mx2 box2 bpolys-cen2)
(if
	(and
		(princ "\nSelect objects to align, by picking faces")
		(setq SS (ssget "_:L"))
		(sssetfirst nil SS)
	)
	(progn
		; Will prompt for point, until the bpoly's elist is displayed:
		; Picking Source Face:
		(setq continiue T)
		(while
			continiue
			(progn
				(setq pt1 (getpoint "\nPick the source face"))
				(command "_.UCS" "F" pt1 "")
				(command "_.BPOLY" pt1 "")
				(if	
					(and
						(eq (cdr (assoc 0 (entget (entlast)))) "LWPOLYLINE")
						(not (member msg '("Function cancelled" "quit / exit abort" "Valid hatch boundary not found.")))
					)
					(progn
						
						(setq bpoly-ent1 (entlast))
						(setq bpoly-elist1 (entget bpoly-ent1))
						(setq vla-bpoly1 (vlax-ename->vla-object bpoly-ent1))
						(setq box1 (vla-getboundingbox vla-bpoly1 'mns 'mxs))
						(setq bpolys-cen1 
							( mapcar '(lambda (x1 x2) (/ (+ x1 x2) 2.0))
								(setq mn1 (trans (vlax-safearray->list mns) 1 1))
								(setq mx1 (trans (vlax-safearray->list mxs) 1 1)) 
							)
						)
						(entmakex 
							(list 
								(cons 0 "POINT")
								(cons 10 bpolys-cen1)
							)
						)
						(entdel bpoly-ent1)
						(command "_.UCS" "W" )
						(setq continiue F)
						; how to set (entlast) to nil ? or not to be a (cons 0 LWPOLYLINE) ? So the code would reset
					)
					(princ "\n*** Try again! ***")
				)
			)
		)
		
		; Picking Destination Face:
		(setq continiue T)
		(while
			continiue
			(progn
				(setq pt2 (getpoint "\nPick the destination face"))
				(command "_.UCS" "F" pt2 "")
				(command "_.BPOLY" pt2 "")
				(if	
					(and
						(eq (cdr (assoc 0 (entget (entlast)))) "LWPOLYLINE")
						(not (member msg '("Function cancelled" "quit / exit abort" "Valid hatch boundary not found.")))
					)
					(progn
						
						(setq bpoly-ent2 (entlast))
						(setq bpoly-elist2 (entget bpoly-ent1))
						(setq vla-bpoly1 (vlax-ename->vla-object bpoly-ent2))
						(setq box2 (vla-getboundingbox vla-bpoly2 'mnz 'mxz))
						(setq bpolys-cen2 
							( mapcar '(lambda (x1 x2) (/ (+ x1 x2) 2.0))
								(setq mn2 (trans (vlax-safearray->list mnz) 1 1))
								(setq mx2 (trans (vlax-safearray->list mxz) 1 1)) 
							)
						)
						(entmakex 
							(list 
								(cons 0 "POINT")
								(cons 10 bpolys-cen2)
							)
						)
						(entdel bpoly-ent2)
						(command "_.UCS" "W" )
						(setq continiue F)
						; how to set (entlast) to nil ? or not to be a (cons 0 LWPOLYLINE) ? So the code would reset
					)
					(princ "\n*** Try again! ***")
				)
			)
		)
		
		(command "_.3DALIGN" SS ""
			bpolys-cen1 mn1 mx1 ; the points must not be collinear! (in this example they are)
			bpolys-cen2 mn2 mx2 ; the points must not be collinear! (in this example they are)
		)
	);progn
);if
(princ)
);defun		

My goal is to represent the aligning close to the Autodesk Inventor's, see this sample video

from 1:37, where the pink part is aligned to the brown one. (Atleast something close to this).

 

At the moment I'm having problems, to find a "third" non-colinear point for alignment. In the following picture you can see the temporary bpoly in yellow, and the points I currently have in red:

 

Feel free to modify the code if you have better suggestions.

For me writing such codes is a hobby and I'm not a real programmer, so I don't need any credits.

(and yes - I thought why not using the bpoly's vertices - but it would took me few days to figure it out)