Reducing Nodes On Curves

[dekoch]

So I thought this would be a simple project but now I am pulling my hair out. This is more of how do I fix this for future reference vs. just someone fixing my issue. I hand traced a logo for a local church from their bulletin. The logo is simple as you can see just has a lot of curves. My questions is when I put this in coral draw and reduce the nodes I am losing pieces of the puzzle or it is making my plasma jump all over when it hits certain parts. Is there a simpler way to reduce nodes and keep the curve look with out all the straight lines. I have been messing with this for the last several nights and all I get is straight lines even on the circle. I even tried some youtube videos where I filled the drawing with paint and remade it as a Bitmap to re trace. Still Line segments. This maybe a very simple fix and i just don't understand Coral Draw yet. Any help would be greatly appreciated.

Damian

[tcaudle]

1. If hand trace it You need to use a polyline tool and just click at the beginning of a curve and the end. Trace each shape to be a closed object (end iies back tot he start. Then select the whole polyline/object with the node tool and right click and tel lit to make all the lines into arcs. Now comes the "fun" part. Go to each segment between the nodes and drag it with your mouse to fit the shape. You can grab the end nodes of a segment and move it or put in some more nodes if you need to to get the fit. Some curves are not symmetrical so you have to put in some more nodes. If a node needs to be s set point make it a "cusp" node. Once you have all the poly-curves into a closed path and the paths are separate objects that DO NOT overlap THEN save the file as a CDR .

2. You then need to export it as an SVG format and it will retain the arcs just like you draw them. CorelDraw and several other packages turn curves into hundreds of short line segments. That negates all the time and effort you made to draw something with curves and circles and minimal nodes. Also once the DXF is exported those nodes are there. So you can have bad DXF files and its a major PITA cleaning them up and turning it all back into arcs! Hand tracing is tedious the first few times you do it and learning the tools and where to place the nodes where you can come back and "rubber band" them . That being said its often faster than auto tracing (especially on lower resolution bitmaps) and having to clean up the objects and ragged arcs. So the line segments happen on the DXF export out of CorelDraw. export in a format that retains the arcs and you will be happier!

[dekoch]

Thank you for your response. Heres the issue now. I redid the drawing and changed my polylines and cleaned up the drawing. Added nodes and reduced nodes where needed. I went and exported as a SVG but my CAM software does not support a SVG File. I am actually a hvac and custom sheet metal contractor and do some signs and such on the side, when I have the time. The Fabrication CAMduct I use does not support SVG. Any other ideas or am I better off cutting the file as is and smooth out the curves with a grinder.

[tcaudle]

Get a copy of DXFtools from www.CoreldrawTools.com for your version of Coreldraw. It replaces the rather lame DXF export filter with one that retains arc and circles and converts fonts to objects so you can keep the Coreldraw original files .

[dekoch]

Thank you for the help. I went ahead this weekend and cut the design with the improvements from your first suggestion. It came out pretty good just needed a little grinding. But I will sure download the dxftools for the future. Thx again.
Damian

[motoguy]

Question for those with more experience than I...since I'm using CorelDraw and SheetCam for my plasma creation (and/or Inkscape, etc), I have no need for the DXFTools products, correct? Sheetcam can import the .svg format, and the issues above are ONLY with the .dxf format, correct? If I was NOT using Sheetcam (or, more specifically, a program that only supports .dxf), then I'd need the DXFTools package...right?

Just trying to make sure I have this correct. Sounds like for anyone using SheetCam, the DXFTools stuff is not needed.

[Capstone]

motoguy, you're correct. SheetCAM, IMO, prefers SVG files, vs. DXF. The OP has a special use case with his software that is sorta out of bounds with most users.

[tcaudle]

DXF is an interesting format. There are two places to mess it uo: On the export (from the original drawing package or a subsequent export from another one) or on the import. Coreldraw along with other packages export a DXF in an older and simplified method where everything is broken into straight line segments. Curves, circles, etc are all bunches of tiny line segments (not even a connected line called a "polyline". SheetCAM does its best to piece things back together but it won't reduce nodes and make nice smooth arcs. Once the file is segment its like Humpty Dumpty . SVG is different. It imports and exports simple and complex arc and circles . So does Postscript and a few other vector formats. So hope that the DXF you get (if its from another source) is not segmented to start with or you get to do a lot of painful conversion and editing..

[Simko]

I am only just learning, but I have had some luck reconstituting a segmented DXF by opening in a CAD program, converting the segments to a polyline, and then opening the file in Inkscape and doing a PATH -> SIMPLIFY

I posted a short list of how I did in this post. http://plasmaspider.com/viewtopic.php?f=77&t=19872

You can see the original segmented file and the reduced node file. Now that I know how to do it, I could fix it in about 5 mins.