#Repeating in deltacad code#

Or a list of vla-objects if more than one offset is created. Īctually, I prefer to use the form (vlax-invoke object 'offset amount) because it returns the VLA-OBJECT of the created polyline, like in case you want to change its layer or color or whatever. If it is clockwise, then (vla-offset object ). If the polyline is drawn counter-clockwise then (vla-offset object ) See the comments at the top for more details. And it remembers that distance, separately from regular Offset's, to offer as default on subsequent use. It even reports how many selected objects were too small to Offset inward by the desired distance, if any. It uses the earlier suggestion here to do the Offset and compare the area of the result to the original, to decide whether to delete the first result and go the other way. But apart from those, it seems to work, on Polylines, Circles, Arcs, Ellipses and Splines, as many as you select. It does still have possible unexpected results with shapes that result in more than one new object when Offset. The result is the attached OffsetInOrOut.lsp with its OffIn and OffOut commands. I started playing with it at the time, then forgot about it for a while, but just got back into it. I thought it might be nice to have a universal routine, that would not be limited to Polylines, but could do anything that could be said to have an 'inside' and 'outside,' and that would not go only inward, but would have commands to go either way. ) end we need need to offset closed polygons to the interior of the polygon at a set distance. If points are sorted in counterclockwise direction, then point is inside polygon if it's left to all connecting lines. is it left or right to all connecting lines. To avoid situation that you mention one would sort points in clockwise (or counterclockwise) direction and test orientation of this apparent (or true) midpoint against polygon points connected into a 'convex hull', i.e.

#Repeating in deltacad code#

In my code I collect all polygon points and and search for midpoint, as a simple solution. Put 'point inside polyline' in the Search window for a variety of threads about the question, including this one where I just used a similar shape to the one in Post 5 here, to illustrate one kind of configuration that can lead to incorrect results. This is why I asked the questions in Post 4. If a routine compares the areas of the original and the last object, which in this case happens to be the smaller one, it will think it has successfully Offset it inward, but it will be wrote:Īnd therein lies the big problem, if the Polyline might be of any shape. In this image, the white is the original, and when Offset outward, by a distance too large in relation to the space between the pointing-at-each-other corners, the result is both green shapes. Only if the new one is larger than the original do you need to get rid of that and (vla-offset) using the negative of the distance to go inward instead.īut there is still the complication of whether any originals might be too small to be Offset inward by the desired distance, which will cause an error.Īnd there's the question of what kinds of shapes they're really talking about. Just (vla-offset) using the desired distance, and compare the area of the result to the original. I would simplify that slightly - no need to always go both ways. If one area of polygon is larger, then remove that polygon - only smaller one should remain. offset on both sides with (vla-offset) function and then check for area of new polygons. (command 'offset' dis e (list xc yc) '' '')

Yc (/ (apply '+ (mapcar 'cadr pts)) npoints) (setq xc (/ (apply '+ (mapcar 'car pts)) npoints) (if (eq (keyValue 70 ent) 1) (setq pts (cons p1 pts))) (setq pts (cons (cdr m) pts) ent (cdr ent)) (while (setq m (assoc 10 ent) ent (member m ent)) (setq npoints (keyValue 90 ent) npoints (fix npoints) pts nil) (setq lyr (cdr (assoc 8 (entget (car e))))) (setq e (entsel ' Select polygon to determin layer name >')) (setq dis (getreal ' Offset distance for all polygons >')) (defun keyValue (key el)(cdr (assoc key el))) (defun *error*() (setvar 'cmdecho' 1) (princ)) (defun C:offset_in ( / *error* keyValue e el dis lyr ss i p1 npoints pts m xc yc )