Hi guys,
I have a file with a spline cut in it, it looks like a half of an
ellipse. I'm using a Prototrak. When I save a DXF and use it to

generate the toolpath, I get a series of lines instead of a smooth
curve when I cut the metal. Does anyone know how to get a smooth
curve like what is in the part file?
Thanks for any assistance here!
-Mike

dxf doesn't recognize spline entities; your spline has to broken into
approximate arcs, a smooth result being the product of manipulating
your cad to match the shape of the spline. it sux, and it looks like
hell but that's the reality of it.

I use to do this all the time with AutoCRAP files and DP Technologies
Esprit X. In DP Technologies Esprit X it was called the LCA function.
It converted lots of tiny lines to arcs so you got a smoother cut and
the wire EDM didn't jerk.
What CAM software do you have or is all you have the ability to lay
down toolpath on a .dxf with the Prototrak?
Jon Banquer
San Diego, CA
http://jonbanquer.blogspot.com /

Most CAM products can.
Be careful that you don't simplify the spline too much as what you are
doing is an interpolation using arcs to replace the lines. If you go
too far your part might no longer be in tolerance.
Jon Banquer
San Diego, CA
http://jonbanquer.blogspot.com /

------------------------------------------
[begin quote]
DXF Group Codes
(version number u14.1.03.)
--------------------
ENTITIES Section
SPLINE
--------------------
The following group codes apply to spline entities.
Spline group codes Group codes Description
100
Subclass marker (AcDbSpline)
210
Normal vector (omitted if the spline is nonplanar)
DXF: X value; APP: 3D vector
220, 230
DXF: Y and Z values of normal vector
70
Spline flag (bit coded):
1 = Closed spline
2 = Periodic spline
4 = Rational spline
8 = Planar
16 = Linear (planar bit is also set)
71
Degree of the spline curve
72
Number of knots
73
Number of control points
74
Number of fit points (if any)
42
Knot tolerance (default = 0.0000001)
43
Control-point tolerance (default = 0.0000001)
44
Fit tolerance (default = 0.0000000001)
12
Start tangent--may be omitted (in WCS).
DXF: X value; APP: 3D point.
22, 32
DXF: Y and Z values of start tangent--may be omitted (in WCS).
13
End tangent--may be omitted (in WCS).
DXF: X value; APP: 3D point.
23, 33
DXF: Y and Z values of end tangent--may be omitted (in WCS)
40
Knot value (one entry per knot)
41
Weight (if not 1); with multiple group pairs, are present if all are not 1
10
Control points (in WCS) one entry per control point.
DXF: X value; APP: 3D point
20, 30
DXF: Y and Z values of control points (in WCS) (one entry per control point)
11
Fit points (in WCS) one entry per fit point.
DXF: X value; APP: 3D point
21, 31
DXF: Y and Z values of fit points (in WCS) (one entry per fit point)
[end quote]
http://usa.autodesk.com/adsk/servlet/usearch/results?la=en&nh &col=wacjprd&col=usuppprd&siteID3112&catID3155&id 88334&qt=d
xf+reference
http://usa.autodesk.com/adsk/servlet/ps/item?siteID 3112&id(82295&linkID’40617
HTH
Bonus question:
What's the difference between a Solidworks spline and a Solid Edge spline?

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