I have a couple more questions and wonder if you can give me some insight. I am thrilled to finally have the SVG export/import working…major win! In my last post, I mentioned that the sheetcam import of these files has improved tremendously…probably even 90% better. When I initially import them, they look awesome. But when I zoom in to get a more detailed look, you can see several nodes have been added to the drawing and several lines look wobbly. There are areas where a nice curve has turned into a point. My husband and I spent the entire weekend experimenting with corel - using different shape tool options with the nodes (smooth, close curve, reverse subpaths, etc) only to end up with the same result. Because this has been such a trial and error, we’ve been drawing the designs on paper with a pen attached to the torch as not to waste metal. The “wobbly lines” in sheetcam are transferring to the drawings.
I’ve been told that this is as good as its going to get. I’m having a hard time accepting that as I have seen plenty of very accurate, gorgeous plasma cut pieces, large and small. Are my expectations too high or are there any other sheetcam settings that can be tweaked to clean some of this up?
I’m attaching an SVG file of one my drawings. I’m going to post another attachment of that same drawing in sheetcam as a comparison.
G-code cannot handle splines or bezier curves so SheetCam breaks them into lots of short line segments. It then tries to find areas of the curve that closely match a circular arc. Those areas are converted to arcs. You can specify a tolerance for fitting those arcs. Making the tolerance tighter will result in more segments but a more accurate shape. You have to make a judgement call as to what is best for your application. Looking at your job the tolerance is quite loose so you are ending up with more error than is acceptable.
Go to Options->application options->drawing import. Try setting the arc fitting tolerance to 0.1mm (0.004") and the minimum segments for arc fitting to 4. Reducing the tolerance or increasing the minimum segments will improve accuracy further but you will end up with more short arcs and short line segments.
Thank you for the information. After reading your post, I checked my drawing import settings. My arc fitting tolerance was at .004" and minimum segments 4. I’ve been playing with them - currently they are set at .0006 and 6. My drawing has improved but as you mentioned I’ve ended up with more short arcs and line segments. I’ll try drawing something today to see how it transfers. I’m still waiting on an email from corel regarding the splines and bezier curves in my drawings and whether they can be converted to polylines or not.
Go back into Corel and remove the extra nodes, straighten the lines and turn the point back into a curve, it is all done with the node tool. try Youtube it will show you how on there.
When you mentioned going back into corel to remove the extra nodes, which nodes are you referring to? In corel, the only nodes in my drawing are the ones that I think are necessary to keep the correct shape. The extra nodes and slight distortions in the file only appear when the file is imported into Sheetcam - in corel its totally fine. Can you clarify?
