I have been cutting shapes into panels by importing dxf files to create profiled arcs and i havn't been able to import either a simple stretched S shape or elipse. Can anyone tell me if there are restraints on dxf imports
Thanks,
Stéphane
Elipse import Dxf Problem
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Stephane Kovari
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Daniel Odom
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Re: Elipse import Dxf Problem
Try saving the ellipse in r12 format if you can or convert splines and ellipse to poly-lines, http://cadsetterout.com/autocad-tutoria ... s-to-arcs/.
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jason galbraith
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Re: Elipse import Dxf Problem
http://www.thermwood.com/forums/viewtop ... pse#p64361
you have to use the pellipse command in autocad. You can then do all sorts of weird ellipses no problem
you have to use the pellipse command in autocad. You can then do all sorts of weird ellipses no problem
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Stephane Kovari
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Re: Elipse import Dxf Problem
How about an "S" shape whithout using two arcs? thats where another problem is, trying to get the profile to follow the outside then inside curve.
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Dennis Englert
Re: Elipse import Dxf Problem
I've been experimenting with AutoCAD Mechanical 2012 lately. Thus far, I've found that some of the restrictions have changed somewhat. Important. What I'm noting is about Mechanical 2012 and the experiments I've initiated. This does not pertain to earlier versions of AutoCAD, that I can not test. I've also tested somewhat on a free AutoCAD like application and the results appear to be the same as Mechanical 2012.
First and still the same, the file must be exported in a Release 12 DXF format. Mechanical 2012 does not offer Release 13 or 14, so I can not verify that.
For Ellipses.
When the system variable PELLIPSE is set to 1, the geometry for the ellipse will be converted into ARC commands (G02/G03) with Control Nesting. I would think that this is the ideal method for the best results in the product.
If the system variable PELLIPSE is set to 0, which is it's default value, the ellipse will still be converted by Control Nesting (not true for older CAD versions), but it will be generated as line segments. I'm not sure about the length's of those segments and you may need to apply a tangency factor with the code G09F# for it to run smoothly. If you offset the ellipse, it will change the geometry to a spline. You can offset it back, if need be. In Control Nesting, the elliptical spline will be generated as line segments, but many more than before. The offset ellipse will change shape slightly, but for the most part not enough to be noticed. Though I've included this tidbit of info, I would always draw the ellipse with the PELLIPSE system variable set to 1.
Two Arcs that are not Arcs.
I'll assume that's a polyline or spline. I've generated both and have had no problem with Mechanical 2012. That being said, it would be difficult to test the many different possibilities. I could see that it would fail if you had a small inside arc and the available tooling would not fit. Other than that, you should be able to use a centerline or outline operation.
The link that Daniel Odom provided relates several options to include methods to draw an ellipse using descriptive geometry, though I found some of the instructions to be a bit hard to understand. This is the same link that used to investigate some of the possibilities and if you review it you'll see that there are other options for various releases of AutoCAD. Anyway, I'd think that if you do draw an ellipse using arc segments, that you would need to use a tangency factor code to compensate for the non-tangent intersection of each of the arcs.
Splines and Polylines both work with AutoCAD Mechanical 2012. Offsetting a spline poses the same results as an Ellipse and does create more line segments. Offsetting a Polyline or PLINE does not appear to alter the number of line segments.
Just to reiterate. I'm using AutoCAD Mechanical 2012. If you are using an older version, such as AutoCAD 2000 or AutoCAD LT, then the Ellipse must be drawn with PELLIPSE set to 1 and splines do not work. In any case, the file must be saved as an AutoCAD Release 12 dxf format.
First and still the same, the file must be exported in a Release 12 DXF format. Mechanical 2012 does not offer Release 13 or 14, so I can not verify that.
For Ellipses.
When the system variable PELLIPSE is set to 1, the geometry for the ellipse will be converted into ARC commands (G02/G03) with Control Nesting. I would think that this is the ideal method for the best results in the product.
If the system variable PELLIPSE is set to 0, which is it's default value, the ellipse will still be converted by Control Nesting (not true for older CAD versions), but it will be generated as line segments. I'm not sure about the length's of those segments and you may need to apply a tangency factor with the code G09F# for it to run smoothly. If you offset the ellipse, it will change the geometry to a spline. You can offset it back, if need be. In Control Nesting, the elliptical spline will be generated as line segments, but many more than before. The offset ellipse will change shape slightly, but for the most part not enough to be noticed. Though I've included this tidbit of info, I would always draw the ellipse with the PELLIPSE system variable set to 1.
Two Arcs that are not Arcs.
I'll assume that's a polyline or spline. I've generated both and have had no problem with Mechanical 2012. That being said, it would be difficult to test the many different possibilities. I could see that it would fail if you had a small inside arc and the available tooling would not fit. Other than that, you should be able to use a centerline or outline operation.
The link that Daniel Odom provided relates several options to include methods to draw an ellipse using descriptive geometry, though I found some of the instructions to be a bit hard to understand. This is the same link that used to investigate some of the possibilities and if you review it you'll see that there are other options for various releases of AutoCAD. Anyway, I'd think that if you do draw an ellipse using arc segments, that you would need to use a tangency factor code to compensate for the non-tangent intersection of each of the arcs.
Splines and Polylines both work with AutoCAD Mechanical 2012. Offsetting a spline poses the same results as an Ellipse and does create more line segments. Offsetting a Polyline or PLINE does not appear to alter the number of line segments.
Just to reiterate. I'm using AutoCAD Mechanical 2012. If you are using an older version, such as AutoCAD 2000 or AutoCAD LT, then the Ellipse must be drawn with PELLIPSE set to 1 and splines do not work. In any case, the file must be saved as an AutoCAD Release 12 dxf format.
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Stephane Kovari
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Re: Elipse import Dxf Problem
Great Information!
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Dennis Englert
Re: Elipse import Dxf Problem
I was playing with Adobe Illustrator a little. There are many graphics applications that can export DXF or DWG files and support layers. Adobe Illustrator does. Corel Draw may also. Possibly, you or your customer only have Adobe Illustrator and you need to work with files from it.
What I've found is that layers in AI (I'm using AI 5.5) are interpreted by Control Nesting, but the geometry of Arcs and Circles are not. I have not tested an Ellipse, but I'd assume the same.
An Arc/Circle can however be converted into straight lines in AI, which does work in Control Nesting. After all, it is a line. The only problem is the line length or the resolution.
In AI, there are multiple steps to convert an arc or circle. The resolution may be an issue.
You can test the use of AI by following the steps below:
1. Select Object>Path>Anchor Points. You'll see a number of points along the geometry. Imagine a straight line between each point. That would normally be pretty rough (an arc is a 3-point arc). Repeat the process and it will generate another series of points. Repeat until you have a sufficient number of points.
2. Again, select Object>Path, then Simplify Straight Lines. Turn on the Preview option and you can play with the slider for Angle Threshold and observe the results. It appears that 0 would produce the best results.
Creating a DXF or DWG file is a function of AI's Export option. It will let you save either as a Release 13 file and newer, not Release 12. That may be a problem.
The resulting DXF file may be adequate for your needs, but if you have a CAD program, then you may want to take the extra step of importing this file into CAD and clean it up there.
While there would be a work flow increase by using a CAD program, the cut quality and consistency would probably be more predictable.
I'll include a little disclaimer here. I am only a casual user of AI, thus I don't know how easy or difficult it would be to efficiently draw entities with any degree of accuracy in Illustrator. To those that do use AI, you need to determine the benefit of using AI. There are however, many low cost CAD programs available, but they do include a learning curve.
Anyway, I was curious and thought I'd look into this option.
Dennis
What I've found is that layers in AI (I'm using AI 5.5) are interpreted by Control Nesting, but the geometry of Arcs and Circles are not. I have not tested an Ellipse, but I'd assume the same.
An Arc/Circle can however be converted into straight lines in AI, which does work in Control Nesting. After all, it is a line. The only problem is the line length or the resolution.
In AI, there are multiple steps to convert an arc or circle. The resolution may be an issue.
You can test the use of AI by following the steps below:
1. Select Object>Path>Anchor Points. You'll see a number of points along the geometry. Imagine a straight line between each point. That would normally be pretty rough (an arc is a 3-point arc). Repeat the process and it will generate another series of points. Repeat until you have a sufficient number of points.
2. Again, select Object>Path, then Simplify Straight Lines. Turn on the Preview option and you can play with the slider for Angle Threshold and observe the results. It appears that 0 would produce the best results.
Creating a DXF or DWG file is a function of AI's Export option. It will let you save either as a Release 13 file and newer, not Release 12. That may be a problem.
The resulting DXF file may be adequate for your needs, but if you have a CAD program, then you may want to take the extra step of importing this file into CAD and clean it up there.
While there would be a work flow increase by using a CAD program, the cut quality and consistency would probably be more predictable.
I'll include a little disclaimer here. I am only a casual user of AI, thus I don't know how easy or difficult it would be to efficiently draw entities with any degree of accuracy in Illustrator. To those that do use AI, you need to determine the benefit of using AI. There are however, many low cost CAD programs available, but they do include a learning curve.
Anyway, I was curious and thought I'd look into this option.
Dennis