[solved] Nodes: am I using too many, and how can I cut down

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[solved] Nodes: am I using too many, and how can I cut down

Postby Guest » Tue May 27, 2008 12:25 pm

I just started using Inkscape the other day, and so far I'm impressed, though I'm still very much the neophyte. There are a bunch of things I don't understand yet, but for now I just have a couple specific questions. I have the habit of being very, very long-winded though, so if you want to skip the background and go straight to the questions, you can find them after the three asterisks below.

First, for some brief background: my main use for this or any graphics editing program is to mess around with maps I create for a pseudo-fantasy fictional world. I used to use Photoshop for this kind of thing, but the fact that I really couldn't zoom in without the whole thing becoming a pixelated mess led me to seek a vector-based program instead. So, I found Inkscape, and I'm so-far impressed - I can actually zoom in and out without that problem.

My problem now is that I think I've made my latest map too big for my own good. Let me explain. I had the coastline outlined in a raster program a while ago, and I imported that image into Inkscape so I could make it into vectors instead. (I traced over it by hand before I realized there seems to be some automatic function that does that, but whatever...) The original raster coastline was very very large so that I could see it in more detail and pixelation would be less of a problem; the vector coastline I traced over it was just as big, even though it doesn't really need to be because I'll be able to zoom it without it being pixelated. So, I ended up with a vector coastline on a canvas that was something like 6000px by 4000px (or something similarly huge). Even though I have a fairly fast computer, zooming in and out of the image slows it down and makes it choke.

Originally I thought the computer choked just because the dimensions were so large. Since they really didn't need to be so big, I made them smaller - eventually to the point that the image appeared on a canvas of about 1500px by 1000px or thereabouts. But the problem continued, and even though I am still very new to vector images, I think I may know the problem: there is a huge amount of nodes.

The typical solution, it seems, would be to use the "simplify" command - according to the tutorial, this should reduce the number of nodes while keeping the same basic shape. On the coastlines for the smaller landmasses, this works fine. But the large main landmass is simply too big. Again, according to the tutorial, simplifying a larger shape will have more "aggressive" results, and I found that to be very true: simplifying the big landmass drastically reduced the number of nodes, to the point that the shape is hardly preserved at any reasonable level.

Now, I tried to get around this by just deleting nodes by hand; that way, I could delete enough to keep my computer from choking, but not so many that, like "simplify," the continent loses its shape. But there truly are a ridiculous number of nodes, and it's simply not practical for me to do it by hand.

I have also tried breaking the one huge landmass into small segments. Presumably, this would allow me to select smaller segments at a time, so the simplify command would not be nearly as aggressive. I have no idea how to even do this, though - the "Break Apart" command (Shft-Ctrl-K), which seems like the appropriate tool, doesn't do a thing.

* * *

So then, I guess my ultimate question (pardon my long-winded introduction) is: first, does having a very large number of nodes lead to drastic computer slowdown, or should I look somewhere else for the cause of that problem? Second, assuming that the answer to the first question is yes, is there any way to cut down the number of nodes quickly and easily? Specifically, can I cut a large shape into smaller ones that the simplify command will be more effective with?

Thanks for reading.

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microUgly
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Re: Nodes: am I using too many, and how can I cut down on them?

Postby microUgly » Tue May 27, 2008 12:48 pm

Yup, that's long winded :) But at least we have full story to help with recommendations.

Anyway, you can still use Simplify for large objects with lots of nodes, just need to tweak how aggressive it is in Inkscape preferences. Under File > Inkscape Preferences > Misc, lower the Simplification threshold value. This might require a little trial and error.

This doesn't seem to be an unusual situation and I wonder the Simplify path would benefit from being able to enter the threshold every time you ran it (perhaps with a preview).

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microUgly
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Re: Nodes: am I using too many, and how can I cut down on them?

Postby microUgly » Tue May 27, 2008 12:53 pm

Oh, and in regards to the PC slow down, my first recommendation is to make sure you're using version 0.46 (I believe it has some performance improvements over 0.45). I've found Inkscape really only slows down when using the blur filter. It's hard to image that if you hand laid down every node that you could have created enough to slow down Inkscape.

A work around to dealing with slow drawings is to separate parts of the drawing into layers and turn off layers you don't need so Inkscape doesn't have to keep drawing them when you zoom and pan the canvas.

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sas
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Re: Nodes: am I using too many, and how can I cut down on them?

Postby sas » Tue May 27, 2008 5:33 pm

Guest wrote:I have also tried breaking the one huge landmass into small segments. Presumably, this would allow me to select smaller segments at a time, so the simplify command would not be nearly as aggressive. I have no idea how to even do this, though - the "Break Apart" command (Shft-Ctrl-K), which seems like the appropriate tool, doesn't do a thing.

Your landmass is presumably a single connected path. "Break Apart" takes the disconnected pieces of a path and makes each one into a separate path (the opposite of what "Combine" does). So if you use "Break Apart" on a connected path, nothing happens.

kristarella

Re: Nodes: am I using too many, and how can I cut down on them?

Postby kristarella » Wed May 28, 2008 10:29 am

I'm not sure whether too many nodes slows things down, but if you use break apart (as sas suggested); first select two nodes, break the path between them (icon in the top bar when using :tool_node: ), do that a few times to make the mainland different sections and then break apart. It'll become separate paths. It's a bit laborious, but maybe with smaller sections the simplify will work better?

Guest

Re: Nodes: am I using too many, and how can I cut down on them?

Postby Guest » Wed May 28, 2008 11:47 am

Thanks, everyone, the suggestions helped. I'll be sure to come back when I inevitably have more questions...heh heh.


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