Is this the case of an open path?

Post about using Inkscape with cutters or plotters.
Kento
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Is this the case of an open path?

Postby Kento » Thu Apr 19, 2012 6:53 am

Over the past few weekends I have tried everything with my limited knowledge to try & understand why I am being left with streaks of colour where ever I have edited nodes re the attached. I am attempting to make the attatched, cutter friendly because if I do not edit the bits that should not be there the cutter will make a mess. My procedure for my editing is as follows. Type out text> object to path> ungroup text > View in outline mode > put letter I am not working on to the back > add nodes where the letters intersect > delete segement between non end points, to delete the parts I don't need. All of this after much trial & error has worked out fine except for the streaks of colour which appears outside of the letters where the node edit was done but I simply cannot get rid of those streaks. Is this because there may be an open path due to the section removed. Can someone explain this to me & is this how you would edit this. Attached are two files for your perusal. Thanks. :?
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Seniors 2.svg
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Seniors .svg
(11.4 KiB) Downloaded 346 times

chriswww
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Re: Is this the case of an open path?

Postby chriswww » Thu Apr 19, 2012 9:20 am

seniors2 file has the issues....indeed there are points not joined together, and open paths get strange looking fill results, i.e. spills. All following in node edit mode. Move individual suspected points around and you will visually see which ones are indeed the culprits. use undo to move things back each time. once you've identified the non-joined overlapping pair of points, select both points more easily by clicking mouse button just outside where they are, and drag over where the points are. they will both be selected even though you can't see that. then use the join nodes tool. immediatelly the fill spill will be fixed.

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brynn
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Re: Is this the case of an open path?

Postby brynn » Thu Apr 19, 2012 9:45 am

First let me understand the whole problem. You want to use a cutter on the text, but you don't want every single letter cut out. You'd rather it cut out the whole word, correct?

The quick and simple answer is yes, those random streaks are caused by open paths. When you select with the node tool, you'll see that some nodes are half the size of most of the rest. That indicates that there are 2 nodes exactly on top of each other. I didn't look at every single one, but the ones I looked at closely, those were the ones where the path was open. (That's exactly what happens when you use 'Break path at selected nodes', but I'm not sure if that's what caused all of the overlapping ones.) So it's simple enough to select and join them.

But closing the path may not be the answer in all cases. That's because there are other places where the path isn't closed, that are not currently showing a problem. But once you start closing them, a problem will eventually show up in those places.

It's going to be tricky to proceed in the way that you're going, because there will be places where you can't hide the open ends behind the next letter. I see this mostly where "i" and "o" come together, and maybe also where "r" and "s" come together. I don't actually know what happens when the cutter reaches an end node. I guess it goes on to the next one, but I don't really know.

I think you're on the right track, though. Instead of editing the paths forming the letters themselves, I would suggest selecting all the letters of the original, and duplicating. Then you can combine all the letters of the duplicate, and edit them to form a single path. Then that will be your cutting line. The way you are going, you'll end up with several open paths, and as said, I don't know what the cutter will do with them.

I don't actually know how cutters work. I probably should have started with that, lol. I don't know how you'll tell the cutter which path to cut on. Or maybe you already know how to do that. It may be that you'll need to convert the text paths to PNG, or something like that. But I'll move this topic into that forum. Then others who use cutters can see it, and help you with that part, if necessary.

Oops, chriswww slipped a reply in while I was typing :D

chriswww
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Re: Is this the case of an open path?

Postby chriswww » Thu Apr 19, 2012 4:29 pm

Sorry Brynn, did it again :)
afaik cutters do take vector input file of one sort or another. being similar to plotters in being able to scale the cut/plot to different size media. also because a cut/plot could only ever be specified in vector and not bitmap format, if that makes sense.
from my little knowledge of the subject, and depending on cutter hardware and software that drives it, sometimes the svg files need to be flattened or otherwise prepped so the paths are OK in terms of hardware process limitations, and most likely need conversion to suitable cutter vector format. As a rather silly contrived example of what you wouldn't ask your cutter/plotter to do: a million small circles as part of background...as it would take like a month for the machine to do.

Kento
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Re: Is this the case of an open path?

Postby Kento » Fri Apr 20, 2012 5:50 am

Thanks very much, like you Chriswww,from my limited knowledge & understanding presently, plotters/cutters do take vector input i.e. eps files they will not recognize bitmap format. Anyway you have put it nicely, well done.

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brynn
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Re: Is this the case of an open path?

Postby brynn » Mon Apr 23, 2012 5:26 am

Hi Kento,
I just had a brainstorm! I originally suggested duplicating the whole path, to create the cutting line, and then use node editing to connect them all. But there's a much faster way. Still duplicate the whole thing, but instead of using node editing to make the cutting line, select the entire duplicate and do Path menu > Union! That will eliminate all the need for node editing :D


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