Node position is OK, but sequence is not

Post about using Inkscape with cutters or plotters.
swarmcatcher
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Joined: Thu Feb 04, 2016 10:25 pm

Node position is OK, but sequence is not

Postby swarmcatcher » Thu Feb 04, 2016 10:53 pm

Hi guys, and greetings from the south coast of England.

I'm new to laser cutting and InkScape and would appreciate some help with a problem with a design of mine.

I've designed a profile I want cut, that has 35 nodes connected by paths. I used the :tool_pen: tool to create them. However, I did this in stages and joined the paths together by selecting adjacent or stacked node and replacing with a single node. I then had a continuous loop. I saved this file as a DXF file and loaded it into RDWorks (as per my hack space instructions). Now, although the machine cut my shape successfully, the head was all over the place, making cuts in a non-sequential order. I believe this to be because of the way I designed the shape, further confirmed by, when clicking a single node with the :tool_node: tool, and then scrolling the mouse wheel to select successive nodes, they were actually selected in an apparent random order.

I've spent some time trying to find an answer, with the help of Google, but maybe I'm not phrasing my question well enough.

Can anyone please point out what I'm doing wrong?

Many thanks

tylerdurden
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Joined: Sun Apr 14, 2013 12:04 pm
Location: Michigan, USA

Re: Node position is OK, but sequence is not

Postby tylerdurden » Fri Feb 05, 2016 12:57 am

A brief google search leads me to think you could manually set cut-order in RDworks.

http://www.sawmillcreek.org/showthread. ... s-question

Feel free to share your svg file here for more assistance on the INkscape side.
Have a nice day.

I'm using Inkscape 0.92.2 (5c3e80d, 2017-08-06), 64 bit win8.1

The Inkscape manual has lots of helpful info! http://tavmjong.free.fr/INKSCAPE/MANUAL/html/

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brynn
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Re: Node position is OK, but sequence is not

Postby brynn » Fri Feb 05, 2016 6:07 pm

Hhm... I've just tried creating some random segments on the canvas, and then joined them together in a random order. But by the time I have a continuous closed path, tabbing through the nodes shows them to be sequential.

Since I don't use a traditional mouse, I'm not sure what rolling the mouse wheel is supposed to do. But I think it's meant to add adjacent nodes to a selection. So if it's a closed path, and 1 node is selected, then with the mouse positioned over that node, rolling the wheel will add the adjacent node to the selection. Roll a little more, and the node on the other side is added to the selection. Roll a little more and the 2nd node on the first side is added, then next the 2nd node on the other side.

So anyway, I can see where that might seem to be random. But that is not an indication of the node order. It's just a way of selecting nodes. If it were an open path, and you selected an end node, yes, it should add nodes sequentially to the selection. But I think tabbing through the nodes is the proper way to show the node order.

If the cutter was jumping all over the place, I wonder if you didn't have all the segments and nodes joined together properly? Because when a path is completely closed, the node order is usually sequential. At least that's my experience.

Or maybe tyler's info will help?

swarmcatcher
Posts: 5
Joined: Thu Feb 04, 2016 10:25 pm

Re: Node position is OK, but sequence is not

Postby swarmcatcher » Fri Feb 05, 2016 6:40 pm

Thanks @tylerdurden, re-ordering in RDWorks is an option, but I only have access to that when I'm next to the cutter, but could try it next time I'm there.

Thanks @brynn, I think I'll experiment with some simple shapes, to try and learn what's going on.

If anyone's interested, I've (tried to) include the file in question.

Cheers

polyhook02.svg
(8.88 KiB) Downloaded 223 times

Maxwell waler
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Joined: Tue Feb 02, 2016 4:23 pm

Re: Node position is OK, but sequence is not

Postby Maxwell waler » Fri Feb 05, 2016 7:15 pm

yes i am agree to with you

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brynn
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Re: Node position is OK, but sequence is not

Postby brynn » Fri Feb 05, 2016 7:18 pm

Everything looks good to me, in your file. I don't know why it was skipping around during the cutting. But your path is all connected properly, as far as I can tell.

swarmcatcher
Posts: 5
Joined: Thu Feb 04, 2016 10:25 pm

Re: Node position is OK, but sequence is not

Postby swarmcatcher » Fri Feb 05, 2016 7:34 pm

Thanks for looking @brynn. :D

~suv
Posts: 2272
Joined: Sun May 10, 2009 2:07 am

Re: Node position is OK, but sequence is not

Postby ~suv » Fri Feb 05, 2016 9:59 pm

swarmcatcher wrote:I saved this file as a DXF file (…)
Could you share the exported DXF file, and provide details about Inkscape's DXF export options used for the file?
In case you installed a custom extension for DXF export - could you share the link to the extension?

Off topic:
brynn wrote:Since I don't use a traditional mouse, I'm not sure what rolling the mouse wheel is supposed to do. (…)
So anyway, I can see where that might seem to be random. (…)

JFTR quoting the manual about selecting nodes with the mouse wheel (might help to understand the perceived "randomness" on selection):
Inkscape manual wrote:Nodes can also be added to or removed from the selection by hovering the cursor over a node and using the Mouse Wheel, moving “up” to add nodes and “down” to remove nodes. (…) This selection technique is especially useful in conjunction with node sculpting.

Two modes are possible: The default mode adds nodes based on the spatial distance from the cursor. If the Ctrl key is held down, the nodes are selected based on the linear distance measured along the path (…). In this latter case, only nodes in the same sub-path can be selected.

~suv
Posts: 2272
Joined: Sun May 10, 2009 2:07 am

Re: Node position is OK, but sequence is not

Postby ~suv » Fri Feb 05, 2016 10:55 pm

~suv wrote:
swarmcatcher wrote:I saved this file as a DXF file (…)
Could you share the exported DXF file, and provide details about Inkscape's DXF export options used for the file?
In case you installed a custom extension for DXF export - could you share the link to the extension?
Forgot to add the reason why I asked for the DXF file / DXF export options: There is a known bug (regression) in Inkscape 0.91 if a document is exported to DXF with the option «use LWPOLYLINE type of line output» checked, which may cause additional lines to be drawn in the exported DXF file:

swarmcatcher
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Joined: Thu Feb 04, 2016 10:25 pm

Re: Node position is OK, but sequence is not

Postby swarmcatcher » Sat Feb 06, 2016 2:12 am

Hi @suv,

I did use the LWPOLYLINE option. I've since re-done the design by tracing over the existing design, but in one continuous loop. I now have some things to try when I'm next at the workshop.

Thanks guys

swarmcatcher
Posts: 5
Joined: Thu Feb 04, 2016 10:25 pm

Re: Node position is OK, but sequence is not [SOLVED]

Postby swarmcatcher » Mon Feb 08, 2016 7:00 pm

Hi guys,

Here's an update. I went to the workshop over the weekend, armed with inkscape and the knowledges gained from the comments above.

I originally exported the inscape file to DXF, with the "LWPOLYLINE" option checked (as it was checked by default). However, when I un-checked it, everything was fine, even with the original drawing, not just the re-drawn ones.

Many thanks to everyone who replied.

Cheers.


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