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Author Topic: Queue lines dont match vector
bdsmith1
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Posts: 3
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bdsmith1
Post Queue lines dont match vector
on: May 6, 2018, 07:44
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Hey everyone,

I'm new to this, so I'm not very good with the PG Controller yet. I'm running a nice PDF blueprint through InkScape (converted to PNG then traced) and it comes out pretty good. I load the vector into the controller and it looks good! The problem is that when I draw the vectors, it looks awful. I've tried different settings of shortest vector length from 0 to 15 and it gets worse the shorter the vector is I go for. The lines don't match at all! I hoped that it was just the way the program rendered the lines, but it doesn't draw so well either. Is there a way to fix this? If not, is there another program that would render a better queue that would allow me to import it to the controller? Thanks in advance for any help. I've been frustrated by this for a while now!
Image

sandy
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sandy
Post Re: Queue lines dont match vector
on: May 6, 2018, 11:29
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Hi, welcome!

That is a pretty loose tangle you've got there. You might already have read http://www.polargraph.co.uk/2016/03/geomerative-polygonizer/ and DaniK and Visualbyte's threads referred to in that blogpost.

Does changing the polygonizer and upping the polygonizer length help? That changes how the vector is loaded and has different effects on drawings of different scales.

Are you tightly zoomed-in on that picture? The "shortest vector" slider will filter out lines that are shorter than the number, and the measurement of distance is in motor steps.

Some of your smallest features (like the text outlines) will just get completely filtered out of existence by a high "shortest vector" setting, and it is very possible to load vector art that simply cannot be expressed by the machine - shapes that fall in between the native grid system of the machine. When "shortest vector" is 0 in these cases, it'll still get a mark of some sort probably, but very small multi-point shapes often get collapsed into the same point, or a plain line.

So some of your features just don't show up: They've been filtered out by the "shortest vector" filter.

It doesn't explain why you've got such inaccurate corner fidelity though - the circles of the screwheads are rendered as triangles. I've sometimes improved situations like this by changing to the other polygonizer style (0) and bumping the polygonizer length up. You'll get a slightly different effect that might be considered better.

But... If your machine just doesn't have a resolution for it, you'll always get some collapsing going on, it's just finding the combination of settings that collapses in the most aesthetically pleasing way.

Improving resolution is discussed in those posts referred to above (DaniK's), but it's mostly a hardware problem that can be improved with a better machine implementation.

Note that Polargraph isn't focussed on being a high-fidelity plotter, and small scale precision work really is where it shines the worst! It is also very easy to forget that the important thing is what it looks like in pen, on paper and the pen, the paper, the speed and the angle and pressure, the stretch and inertia of the gondola, the friction of the tip and the gentleness of the penlift all have an effect on the impression that is greater than the exact shape of the corners could deliver. I've often got fixated on trying to get small details rendered on screen, and forgotten that when I'm actually drawing it, the pen tip itself is physically larger than the entire detail - it's literally impossible for that shape to be expressed by that pen. That's the main reason I have never worked to improve that base resolution - at a certain stage it all collapses into the same gloopy pen mark.

Hopefully that helps, let us know how you get on!

sn

bdsmith1
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Posts: 3
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bdsmith1
Post Re: Queue lines dont match vector
on: May 10, 2018, 21:05
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I've gotten some very good vector drawings out of my machine. The drawing in question is on a 24 by 24 inch drawing surface, not small at all compared to other things that I've done. Polygonizer length has been adjusted and played with with no results. This shortest vector length is set a little high, but I've set it as low as 1 and it doesn't improve, just makes the lines shorter. I 3d printed some pulleys to work with my beaded chain that I found at Wal-Mart(actually worked well) The mm per revolution is about 101mm. That is a bit high, but I have nema 17s that have done good work before. I'm almost positive this is a software thing. I haven't read the article yet, but I'll take a look. Thanks for the help. I'll keep you posted if I find a fix.

indignantw-
orld
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Posts: 5
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Post Re: Queue lines dont match vector
on: May 26, 2018, 07:55
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I am having the same issues with a machine that has worked in the past (see my post yesterday) I winder if something has been updated?

sandy
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Posts: 1334
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sandy
Post Re: Queue lines dont match vector
on: May 29, 2018, 22:29
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@bdsmith1 have a look at http://www.polargraph.co.uk/forum/polargraphs-group2/troubleshooting-forum5/draw-vector-gives-shakey-lines-thread704.0/#postid-4024 for some developments - might help.

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