Fast Way to "Centreline" many complex outlined paths?

Stephen Marsh

Well-known member
For our "CAD" cutter, we need a single vector path.

We sometimes receive finished layout files with dies from various Esko systems that are outlined into two paths with a fill - rather than being a single path with a stroke. We are not supplied with the original CAD die/knife.

I know that I can select the Illustrator outer or inner path and then use the "path/offset path" command to offset half the distance between the two paths to create single path that splits the width of the line - however this is a lot of work when there are complex knife/die shapes to work with.

Does anybody have any tips or tricks?...or am I left to doing this the manual way if it is not practical to ask for better data?


Stephen Marsh
 
Basically what you are doing is what I do. There are a few other ways but they are every bit as burdensome. You should try to work with the people supplying the artwork and ask them to stop converting strokes. I usually argue/inflict inconvenience upon them until they make it right.
 
Thank you for the confirmation chevalier. Al, do you have an action to share, or did you mean to try recording one to make this less tedious? Illustrator actions are really poor when compared to Photoshop, it is as if the programmers just did not put in the same work.

Back in the days of Adobe Streamline, there was a feature to autotrace via a centreline, rather than with a fill. In desperation I looked into Live Trace, however it does not offer a single centre line option as it's predecessor did (so much for progress). I also looked into the opensource Inkscape, with no luck in finding a faster solution.


Stephen Marsh
 
No I don't have one for that, so I meant record the way it works manually for you. And I agree that Illustrator's Actions are inferior. The two programing teams probably work in different buildings, or different campuses (campii?).

Al
 
I wish Illustrator had a more open API or just had XML support like InDesign. I'd just create my own plugin for this (among other things) and profit from it.
 
Stephen

I have made some pretty involved Illustrator actions to create imposition templates and then stepping templates. If you want to send me one of your files with instructions on what you want to achieve, I have a couple of long business flights next week and always love a graphics oriented project to help fill in the "sitting in a tube" time.
 
Thanks Bill, I appreciate the offer, attached is the incorrect customer supplied knife (outlined-knife.pdf), created with a fill and a closed path.

Also attached is an in-progress version that I have fixed up with a single stroked path (single-path-knife-inprogress.pdf). This is the result that I am looking for so that the CAD cutter/creaser can follow the contour (the stroke is not important, it is just visual).

I would like to push this back to the source as I know that they should have the correct CAD file, however sometimes I have to deal with what I am given.

EDIT: Perhaps delete your email address from your last post so that SpamBots don't harvest it!


Stephen Marsh
 

Attachments

  • Knife-Archive.zip
    182.7 KB · Views: 205
Last edited:
Hi Stephen,
Do you still have Streamline and a mac to run it on? I remember centerline, could probably get SL installed on an old machine and try out your file if you'd like.
-Dan
 
Hi Dan, no I don't have access to Adobe StreamLine anymore, so it would just be an academic exercise rather than a practical solution.

Stephen Marsh
 
Greetings Stephen, Sorry for my delayed response. I am in a training class all day and I would swear that the hi speed wi fi in my hotel is bouncing to my room via a modem. A few questions:

1. Is the file you sent me named single-path-knife-inprogress.pdf your final file?
2. Is the distance you are splitting to make the final dieline always the same, or do you need to measure each expanded stroke set of elements to determine the offset path number.
3. I have made many rotary flexo dielines, however they rarely required any additional graphic elements except the outer dieline, with an occasional perf. Are there more lines necessary on a successful die for your application than an outer perimeter, eg knife cuts for flaps, etc?

I can automate some of this but I am not sure you would gain much. With the answers to my questions, I will "play" at bit more.

-Bill-
 
Greetings Stephen, Sorry for my delayed response. I am in a training class all day and I would swear that the hi speed wi fi in my hotel is bouncing to my room via a modem. A few questions:

1. Is the file you sent me named single-path-knife-inprogress.pdf your final file?

Yes, I only built the bare minimum to show what the intended outcome would be. Of course, there is a whole let left to do, which is why I was looking for an automated method rather than manual.


2. Is the distance you are splitting to make the final dieline always the same, or do you need to measure each expanded stroke set of elements to determine the offset path number.

I would hope that all the outlined paths are the same thickness in each knife/die file.

From one file to the next? I am not sure.


3. I have made many rotary flexo dielines, however they rarely required any additional graphic elements except the outer dieline, with an occasional perf. Are there more lines necessary on a successful die for your application than an outer perimeter, eg knife cuts for flaps, etc?

I think that the file that I posted was a worse case scenario, there is a whole lot of extra junk in there which is probably not necessary for cut-n-crease operations. If an automated method can "centreline" everything, then I could just delete off the junk (before or after).

I can automate some of this but I am not sure you would gain much. With the answers to my questions, I will "play" at bit more.

-Bill-


It is a tough challenge, so I am more than happy with whatever you come up with Bill! I really appreciate your time looking into this.


Sincerely,

Stephen Marsh
 
Greetings Stephan - Don't mean to be a broken record, but in order to test my actions, I need to know what kind of file you receive and what your final file needs to look like.

You indicate that "I only built the bare minimum to show what the intended outcome would be. Of course, there is a whole let left to do". Is it possible for you to send me your final file to compare to the original file named outlined-knife.pdf?

Thanks

-Bill-
 
Thanks Bill, I have attached a new zip file PDF.

It has a spot colour for cut and and separate one for the crease. For sake of example, this is all that would be required.

In this case it is not too much manual work to fix the outlined paths into a single stroke, however I would like to automate this as much as possible as some jobs would be more complex and time consuming. I will of course push for the correct data to be supplied, however sometimes I have to work with what I am given.


Stephen Marsh
 

Attachments

  • single-path-knife-inprogress2.zip
    45.8 KB · Views: 189
Greetings Stephan,

As I work through this I noticed in the last file you sent me some unconnected areas in the dielilne. I have attached a PDF file that highlights two of these areas. Can the die maker use the file with these unconnected areas or do you need to fix these?
 

Attachments

  • UnconnectedAreas.pdf
    67.7 KB · Views: 191
Greetings Stephan,

Typed a bit too fast - the exploded view in the upper right shows what I, being a novice with these types of dieline, would guess to be a misalignment. Is the intersection of the outer dieline and what I am guessing is a crease line off?
 
Hi Bill, for this exercise, it is not too big a deal about the alignment, think of this more as a proof of concept if that helps. It is early days for me using a CAD cut-n-crease, at this early point I will hazard a guess that it does not matter if paths are connected or joined. Please don't spend too much time on this unless you like the challenge!


Stephen Marsh
 
Greetings Stephan,

Love the challenge. I have attached a zip file containing a maker document and an action. Open the maker document, load the action, paste the dieline art from the customer in the clipboard and start the action.

I have tested and refined this a few times and it has worked correctly each test. When you get to the offset path action component I had a negative number set in my original action, however when I saved the action and reloaded it the number became positive and that is why I had to put that extra stop reminder. If you have not used actions you may need some additional instructions - let me know.

-Bill-
 

Attachments

  • MakerDocument_and_Action.zip
    192.2 KB · Views: 208
Thanks Bill!

I am still using CS5, I receive an error message when opening this MAKER.AI file. Is it possible for you to save as CS5 or earlier and or with PDF compatibility to make this more accessible?

I am not sure if there are any action issues with running an action created in a later version or not?


Stephen Marsh
 

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