help w/spline output as DXF

I'm doing some artsy tracing stuff in SolidWorks and exporting via
DXF to my CAM software. The problem is that splines are being broken
into line segments.

I had thought that the problem was one of translation on the CAM
software end, but when I open the file from SolidWorks the splines are
line segments there as well.
I've seen posts on this issue in the past, but have never seen a good
solution.

Any ideas?

 

Hello to you.

I try to your problem - the file I make from the solidworks have spline in
solidworks but no the splines but only the many lines create in dxf.

I perhaps one idea have about the formats r12 who can make no spline but
again to try many formats newer and only the many lines comes in.

Upon the usage of word editer to iterogate file of dxf I find no define of
spline. So you make idea of bad outputs coming from solidworks is correct
idea. Not the reading in but of the writing. What is to be done ? I can
you not tell.

By these ways, will not the cnc make the lines anysway for to program with?

Sincerefully,

Habib

 

Sorry reply to it twice times.

I make experiment and find format autocad 2002-2004 format output by the
solidworks makes to splines into the dxf and come back in also to
solidworks, corel draws and autocad - so maybe version before this one makes
it bad. Try maybe make version of the dxf most highest one possible.

May be this can be also to be read by you program cnc.

Ok if to try again please and thanks you.

Habib

 

Habib,

Thanks for your reply. I don't see an option for output to autocad
2002-2004 format. I should have mentioned that I'm running 04sp0
version of SolidWorks. I see same results in using dwg output.

In answer to your question about cutting the line segments, they are
varied in length and as short as .005". Each segment requires a line
of gcode and there are thousands of them. For each line of code, the
laser head attempts to speed up to max cut speed and then ramp back
down before hitting the end of that cut segment and starting the next.
Running this code results in what looks like a twitching of the laser
head. This can't be good.

Dave

 

Hello to you Dave-

I make the difference dxf reversions by hit the options button upon save. I
run the services pack 2004 sp1.

I am think the sp0 is also working the same way. Maybe they change but it
can be tried.

It sound like the extra largest headache for that laser to be programed this
way.

Best of the lucks.

Sincerefully,

Habib

 

I'm doing some artsy tracing stuff in SolidWorks and exporting via

I use to run into this problem frequently with drawings done in AutoCAD.

The CAM package I was using at that time was DP Technology Esprit X
which had a tool called LCA Conversion. What LCA conversion did was
convert the line segments to arcs using a tolerance that could be set by the
user (me).

What I ended up with were parts that had a much smoother surface finish.
The wire EDM machine (AGIE's) did not jerk like crazy, either.

In my opinion you will either need to recreate the part or use a tool like
DP Technology Esprit X had.... LCA Conversion.

You might also want to post your problem in alt.machines.cnc. to get
other machinists ideas on this.

jon

 

Anyone ever suggest using IGES instead of DXF? Find an actual

Hi Cliff.

Pathetically SolidWorks has absolutely no support for 2D output to
IGES and equally pathetic is no 3D output to DXF (although customers
need and request this year after year).

I'm sorely amazed that they presume that nobody needs this or even
receives or needs to generate these types of files for their less
CAD-capable vendors. Sorely amazed, but mostly sore.

My favorite DXF trick is when the detail circles come in as a
collection of lines, just like the splines described above. I have to
laugh my ass of at this - and then cry, then create a 3 point arc in
AutoCAD and then erase the crappy mess then SolidWorks translator made
when trying to output a CIRCLE!

Regards,

SMA

 

Hi Cliff,

Yes, about 500 bucks as I remember.

For drawings, I beleive, which are still widely used by many people
(grin).

No arguements there, but I have used a couple "pure 2d" systems that
allow an iges output/input of a drawing (anvil-1000 & cadkey if I
recall correctly from the anient mid 90's)

This is problematic. After r12 things go to hell rapidly. I think
that the post r12 standard was not published and therefore people who
had to make translators had more work to do in reading/writing post
r12. R12 can't do, as you know, some entities like ellipses and
(maybe) splines, mtext, etc.

The sending system is here on my machine and so is the recieveing
system. Unfortunately SolidWorks does not have this level of
tweakability.

That's 100 per cent correct, but the problem is that the sending
system does not output the correct data for a detail circle. I find
this highly laugable.

Try it for yourself. Make any solidworks drawing, create a detail
view and then write out a dxf file. You will not see a collecton of
lines, not a circle.

Are they woman-readable too? LOL!

I'm not adding much useful to this thread.

As delectible as this discussion is, I'm pushing myself away from the
table!

I'll be in the vomitorium if you need me Caesar . . .

Regards,

SMA

 

How do you suggest he do this ??? He admitted in
alt.machines.cnc that he has *never used SolidWorks* !

Further, he fails to understand that many CNC machines allow
a .dxf file to be imported so a toolpath can be created.
Hurco and Bridgeport machines have controls that import .dxf
files. Neither allow input of IGES files !

The problem of polylines is so common that better CAD/CAM
systems give you tools to fix the problem. I have already
mentioned DP Esprit X's LCA conversion tool.

He just learned in alt.machines.cnc that Autocad IGES is an
extra add on. Thanks for helping him to understand how
SolidWorks often fails to give machinists the needed tools. :>)

Perhaps one day when he upgrades from Windows 95 (which he
admits is the only MS OS he has) he might be able to try
some of what you suggest. SolidWorks Corp. would probably
let him take advantage of the unemployed engineer software
deal. Should he actually make the effort, he might be able
to see for himself what SolidWorks has to offer instead of
being spoon fed on Usenet. Sometime in the future he might
actually realize that everyone would not be better off with
Unigraphics as he frequently claims.

This is just too funny. I have not laughed this hard in weeks. :>)

Thanks !!!

jon

 

And those "splines" may not be what is usual for a NURBS spline ...

interesting. Ive been exporting my own file formats directly from SW
views for a few years now (using various API "GetPolyLines" calls),
and some of these calls allow for splines.

When first setting up this code, I was unable to find any example
splines to 'parse', so I merely put some code in to notify me when it
came across a spline, where then i could use the newly found spline to
reverse engineer what SW was giving for information.

Its been a few years now, and, like an ugly girl on a Saturday night,
Im still 'waiting for a call' .....

 

Still looking for the ultimate solution, but thanks for the help so
far. As it turns out, CAM fitting splines is not a good option either.
The GCODE produced is about the same in length as using line segments.
I really need a simple way to convert splines to arcs. I can start
with arcs, but it will be extremely tedious in comarison to using
splines. I will find a solution, but it looks to be a long,
frustrating road.........

 

Already gave you the "ultimate solution" ... redraw the part
in your CAM system.

What is the tolerance you must hold on this part ? If it's
not extremely tight, DP Esprit X *always* produced smaller
files for me on polyline conversions.

jon

 

Your going to have to continue 'waiting for a call' because
SolidWorks Corp. still does not understand what may
machining job shops really need, nor do they seem to care.

Be nice to see Cadkey users move to VX because you better
believe VX has an entirely different attitude toward
machining job shops.

jon

 

Repeating work is hardly an "Ultimate" solution, at least imo.....
That's what I'm doing now. Buying another CAM system because is not an
option either.

 

What choice do you have with SolidWorks and ProCAM ? Even if
you were using DP Esprit, when you convert from polylines to
arcs you are going to loose some degree of accuracy. Many
times this does not matter if your tolerance is wide open as
many profiles often are.

At one time both MasterCAM and SUFRCAM were suppose to run
inside of SolidWorks. Why do you think both companies killed
development on their respective projects ??? I got an ear
full from the former SURFWARE employee who acted as liaison
between SURFWARE's owners and SolidWorks Corp. on how difficult
SolidWorks Corp. was to work with. Have no doubt there was at
least some truth in what he had to say. I have heard the same from
Robert White former owner of FastSURF and several others at
CAD/CAM companies who need to remain nameless.

It's pretty common knowledge that SolidWorks Corp. does not
spend a lot of time thinking about many of the tools that
are needed to actually manufacture a part. This has been the
case for a long, long time now.

Why not use something like Rhino to clean up the mess that
SolidWorks puts out ? By the time SolidWorks Corp. fixes the problem
you and I will both be very old.

jon