Steps to Recreate:

  1. Create a Rectangle without a fill but with a stroke (Empty rectangle)
  2. Select "Smart Guides" & "Snap To Point" from the View Menu.
  3. Select the "Line Segment" tool from the toolbar and draw two diagonal lines joining the opposite points of the Rectangle (Make sure the anchor points get snapped to the pointer)

You will get a similar image.

enter image description here

  1. Now select everything you've drawn, and select "Divide" option in the "Pathfinder" toolbar, in-order to separate the shape into 4 segments.

  2. But now you'll also be getting the following artifacts on the four corners resulting due to the corner anchor points not being joined.

enter image description here

If you now use the "Direct Selection" tool and drag one corner point outwards, you'll see it has been correctly divided into 4 smaller shapes, but I would like the overlapping points to be joined in four corners.

Note: If I try to join them by selecting all the points in 1 corner, it complains about them not being on the same shape, which is also correct since I used "Divide".


My question is, how to I join these points that are perfectly overlapped, but when they belong to different paths?

Additional Information: I've already tried the "Average" -> "Join" workaround. Still get the same error.

enter image description here

"To join, you must select two open endpoints. If they are not on the same path, they cannot be on text paths nor inside graphs, and if both of them are grouped, they must be in the same group."

1 Answer 1


The corners are simply sharp corners. You can't join un-opened anchor points (corners).

If rounded corners work you can simply alter the corner options in the Stroke Panel.

If you want sharp corners, you need to rethink construction. You can expand the strokes and then use Pathfinder > Merge to create the overall shape. But that will combine everything and not result in 4 separate objects.


In reality, this is a common issue which Illustrator fails miserably at. The corners are sharp due to the Miter Limit on the stroke panel. But you can't adjust the Miter Limit well enough to actually remove the points on sharp angles. If your original shape were more square than rectangle the corners wouldn't do the same thing. But with sharp angles, you simply need to rethink construction. Without knowing your final goal, I can't really offer anymore solutions. In some cases a custom arrow head which is a 45° point helps, but not for closed triangles with sharp angles.

  • Thank you very much for the excellent explanation!! My real goal was to create a complex shape and break it down into smaller shapes using line segments drawn randomly across it and then to use "Divide". This was to create an explosion effect and move away the smaller pieces from each other. But when I did that I found the sharp corners piling up and creating weird artifacts. Which was when I tried to re-create it in this simple form. But your explanation is perfect and now I know what goes on and why only sometimes this happens. So I will try to rethink a better approach!. Thanks alot!
    – Neo
    Commented Nov 24, 2013 at 20:01
  • Glad I could help. If the pieces aren't on top of each other you shouldn't notice the odd corners. The outlines are perfect on the triangles, the problem is a direct result of adjacent shapes with sharp corner angles.
    – Scott
    Commented Nov 24, 2013 at 20:08
  • If one inserted infinitesimal horizontal line segments between the diagonals and vertical lines, and infinitesimal vertical line segments between the diagonals and horizontal lines, one could produce a clean image. Not sure how best to ask for infinitesimal lines, though.
    – supercat
    Commented Jul 31, 2014 at 21:47
  • @supercat unnecessary. Easier, MUCH easier, construction is to merely draw a rectangle with a thick stroke and then draw the cross members to end at the corners, on top of that thick stroke. The issue the original question has is that all path segments end at corner points. Back them off the corner a bit and it's not an issue.
    – Scott
    Commented Jul 31, 2014 at 21:50
  • @Scott: The latter approach has the disadvantage that it requires that the correct placement of the corner points depends upon the line thickness. Adding infinitesimal-length segments at the joins would yield a drawing which would correctly render even if the line width and line-join styles are changed.
    – supercat
    Commented Jul 31, 2014 at 22:03

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