Arc Orientation?
THREAD FROM ARCHIVE
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From: PeteB Date: 24 Jan 1999
I'm currently using Autocad 14 for making my DXF files and I'm having a problem with arcs. Once my design is finished I join all my lines/arcs into a polyline then explode it (This puts all my lines/arcs in order). The problem is my arcs always come out reversed, the only way I can fix it is by edit the .sbp file.
Any suggestions on how to fix this problem?
A trick I made up goes something like this: Draw your line design using normal cad commands. Then change to another new layer and use a different color. At this point think about the tool path you would like and start using gravity line points around the project. Save the drawing and erase the original layer leaving the new layer. Make shure your origin point is set up properly!!!
Try it and experiment with your own Cad system. It's a great way to control the exact tool path.
Maybe someone can help me with ellipses; I am using AutoCAD r14. What is the easiest way to create a .sbp file of an ellipse? Currently I draw the ellipse then trace with polyline then spline and erase the original ellipse. This is very time consuming and dose not provide the best results.
Any suggestions would be greatly appreciated.
Tim W.
New Member
TO CREATE AN ELLIPSE USE THE CC FUNCTION IN SHOPBOT. CC IS CUT CIRCLE, BUT YOU CAN USE THE PROPORTION FACTORS TO EITHER STRETCH IN X OR IN Y, THUS CREATING AN OVAL (ELLIPSE)
Tim,
Phil has the same answer I would have except, I would use the CP command and place a new color on the point, the center of the elipse. Then I would edit the .sbp file in a word processor with a find 'MZ, XX'. This would work on all elipses on the X-Y axis.
Ron B
Phil & Ron,
Thanks for the info.
What I neglected to mention is that the ellipse is 60" x 108". So what I am really trying to do is cut a portion of an ellipse. If I enter the dimensions 60" x 108" into CC, Obviously the line runs off the table. Do I have to text edit the .sbp file to cut only a section of the ellipse? UUUGGHH I am confused!!!
I am probably making a simple solution very difficult, Huh. 8>(
Tim W.
New Member
You can draw an ellipse in Autocad or any CAD program and then save the file as a dxf file.
Position your ellipse so that the 60 x 108 portion that you want cut will fit on your material. In this way the origin or 0,0 of your drawing will be at the right spot to cut on your material.
Save your ellipse as a dxf file and use the shopbot dxf coverter to get the sbp file
There are a few more steps to do but hopefully this will get you on the right track. I'll let you discover all the steps for yourself but if you can't get it to work with this instructions, let me know.
Hi Tim,
Along the general lines suggested above, you can still use CC or CP to do your elipse if you know the starting and ending angles.
If what you are creating is a symetrical arch, then the CA function might also do it for you.
CP and CA are both circle function in the new software that you can explore with the 2b8 beta download, here. There are a couple of glitches in the 'Fill-in Sheet' so you'll have to enter the parameters (we'll have that fixed shortly).
I draw in Autocad, then export dxf. I then import to Mastercam. My Manual says that splines are not supported in dxf. When I import dxf with ellipses they do not show up. I have to redraw them again in Mastercam. I think the best option is to use CC and scale x & y
Dale
PeteB,
The most recent UX converter in SB2.8 will now convert polylines with arcs (A.K.A. polyarcs) without exploding them. This will keep the entities in order and the arcs in the right direction. You can also order the cut, the first entity drawn is the first cut.
As for the double lines of code from the DXF converter, I will be looking at any sample files that are sent to Ted regarding this problem.
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