Error Message: can't join points

[Mariner2]

I have been working in AI CC bringing together a very large complex polygon made up of quite a few bits and pieces of other polygons.  Having successfully joined together the bit and pieces I now have seven remaining arcs that make up the finished structure.  When I try to join these arcs together (arc 1 to arc 2, arc 2 to arc 3, arc 3 to arc 4, etc.) by selecting the end points with the Direct Selection Tool and hitting CTRL J  I receive the following error message: "Can't join the points.  Can't add an anchor point."  There are no compound paths, there are no groups, I have cleaned the paths so many times they are very nearly shiny.  I have been using AI since before the CS series, making just these kind of shapes, and have never seen this error message before.  What's up? 

Title edited by moderator. Was “Error Message”.

[Bill Silbert]

This is something that should work without a problem. I tried to duplicate your problem but could not. It seems possible that this could simply be a case of corrupt preferences. Try resetting preferences and see if it fixes the problem.

To reset preferences on a PC:

You can try the quick way of resetting on a PC which is to hold down Ctrl + Alt + Shift when launching Illustrator and respond affirmatively when asked if you want to reset. There have been some recent reports that the window asking if you want to reset is not popping up but that the prefs are being reset anyway. If this works great but if it doesn’t you may have to manually delete them.

To do so:

On Windows 7 and above the preference files are hidden. To find them go to the Control Panel and open Folder Options and then click the View tab. Then select “Show hidden files and folders” or “Show hidden files, folders or drive options” in Advanced Settings. Then delete (or rename) the folder at the end of this path: C:\Users\[User Name]\AppData\Roaming\Adobe\Adobe Illustrator [version number]\ Settings\<Language>. Make sure that Illustrator is closed when you do this. When you relaunch the program it will create  new preference files and the program will be at its default settings.

The advantage of manually deleting preference files is that after you’ve reset up the program (make sure that no document window is open) to your liking, you can create copies of your personalized “mint” preference files (make sure that you quit the program before copying them—that finalizes your customization) and use them in the future to replace any corrupt versions you may need to delete.

[Mariner2]

I did the manual delete of the preferences, fired up AI, opened my file, selected 2 end points, hit CNTRL J and got the same old error message.  Somebody, at some point in time, created this error message.  Was the programming not documented?

[Aristarco Palacios]

I think it has to do with the complexity of the polygons and the RAM available. Bill Silbert says he "tried to duplicate your problem" but how did he do that? Did you send him your file and he followed your same steps? How much memory you have installed on your machine? How much does he have in his? You can't duplicate your problem in other machine if the conditions are not the same.

Part of my job is making maps of my state in ArcMap and then "polish" them in Illustrator CS6 in a Win10 box with 8GB of RAM. After joining two thirds of the map with no problem, I get the error. The last third is the most complex of the three and will give the error even if I try to join it with any of the other two, first. I have 55,498 points and won't let me add more.

In other forums they claim to solve the problem using the Unite option of the Pathfinder but in my case it just closes the complex polygon and the simpler one as two separate polygons. No workaround for this.

Has anyone solved this problem? Has someone solved it by adding more RAM to the machine?

[Edward Pugh]

I'm a physiologist at UC Davis.  Our group generates complicated figures with a number of different data analysis and plotting programs (e.g., Matlab, Igor, Python, R-) and often creates figures for publications that combine high resolution imaging files from confocal microscopy, optical coherence tomography, or other sources.  I recently ran into a very frustrating problem which has just resolved, in part to comments made by Aristarco.  The problem arose with Matlab-based figures which plotted running error "clouds" surrounding data traces with the commands "fill" or "patch" (the running error is displayed in the Matlab figure as a "cloud" surrounding but rendered behind the data trace):  when the Matlab figure was saved as a pdf file, Illustrator (CC 2018) would not import the file so that all the elements could be manipulated (e.g., for color, line thickness, or alignment), as would be possible with a normal pdf: rather, all elements in the pdf were "frozen" together.  I tried many different "tricks" in Matlab -- e.g., plotting the points without "filling" in between the boundaries with "fill" or "patch" -- to no avail.  In one such effort, the pdf was normally rendered so that the boundary lines could be selected, but it was impossible to join the ends to make a closed contour: efforts to join the end-points invariably resulted in the error message: "Can't join the points.  Can't add an anchor point." 

Aristarco's comment got me to think about the # of points that comprised the error boundaries as the possible source of the problem, so I rewrote the plotting script in such as way that the number of points for the error boundaries was reduced more than 10-fold, and lo and behold, all elements of the resultant pdf were accessible in the normal fashion.

The bottom line appears to be what Aristarco surmised: there is a limit to the # of points or elements either in the pdf-generating script or in AI when it tries to open the pdf file.  When that # is exceeded, the pdf no longer appears to be a fully vector-graphically rendered object.  (I can't say yet whether the pdf-generating script in Matlab, the AI-importing program (or both) is causal.)

Thanks also to the other contributors to the thread, in particular to Mariner 2 for starting it with the full error message from AI, as this is what led me to the thread after several days of tedium and frustration.

PS I'm using a MacBook Pro running macOS High Sierra, with a 2.9 GHz core and 16GB of memory.

[creativejake]

Could those arcs be grouped with another object? Try selecting and Ungrouping, or also, I have found that complex shapes may also have Appearance issues not allowing to join. In that case, I have had to go to Object->Expand Appearance for the joining to work.

[Aristarco Palacios]

Hi!

Objects are not grouped. Expand Appearance is grayed out and applying Object > Expand does not solve it either. I think the object has way too many anchor points and Illustrator can't add more. If I cut the problematic polygon in smaller segments and start joining them, there's a point when the error appears. You can choose any point to start joining. When the polygon reaches a certain number of points, the error appears.

Still think it's a memory problem. Or maybe the data type chosen to keep the count of points won't allow more than 32,000 points. I erased point by point and tried to join paths. They joined when the sum of points was 32,000 exactly.

I just hope someone solves this in the near future.

[Larry G. Schneider · Accepted solution]

What happens if you use Object>Path>Simplify and use 95% in the curve dialog? If you are using something from ARCMAP, it may help.

[Aristarco Palacios]

It helps. Point count falls dramatically and I can join the polygons. It's good for zoom levels that hide distortions. Does not work when printing large format, accurate maps but I can live with that. Thanks!

[Larry G. Schneider]

You can always bump the number up from 95 to some thing like 98 and are if it still works. You really don’t need most of the precision a GIS system can provide.

[jane-e]

What happens when you use the Selection tool instead of the Direct Selection tool and then Ctrl + J on your selected shapes?