[greasywheats]

Hi all,
Looking for suggestions for a problem that I am having with my CNC operator who runs Enroute V5. I am providing AutoCAD files saved as .dxf files that have several curves. However, when he imports it into Enroute, the curves are showing up not smooth...they are clearly made up of individual line segments strung together in a curve, rather than a genuine, smooth curve.

Can someone please suggest any setting either on the AutoCAD side or the Enroute side to fix this? I know there is a cleanup tool in Enroute, but I don't want to make the corrections in the G code if there is a way of simply getting the .dxf file to translate properly (ie- smooth). There are hundreds of curves per files across several files.

Thanks in advance for your help!

[ger21]

Don't use splines in AutoCAD.

What version .dxf are you using? If it's version 12, then the spines are being converted to line segments when saving the file, as version 12 .dxf doesn't support splines.
If you're saving a newer version .dxf, it's possible that Enroute is converting the splines to straight segments.

[greasywheats]

Gerry,
thanks for this insight. I am saving them as .dxf 2004 (I am running ACAD 2005). Any ideas, other than to upgrade my ACAD version?

[ger21]

Upgrading AuotCAD wouldn't make any difference at all. I think the issue is Enroute.
Any chance you can post the .dxf here? Or at least a sample with similar curves?

[greasywheats]

Gerry, here you go. This is a simple test file that I sent my CNC operator and he confirmed that Enroute still translates the curves as lines segments. It looks fine zoomed out, but when zoomed in you see the "faceting". And when we have cut plywood using a file like this, that faceting is evident in the machines path and the final product.
Thanks for any input.

[ger21]

Definitely an Enroute issue. It's just a standard polyline with arcs. Even free CAM programs would have no trouble converting that to g-code with arcs.
Perhaps there are some Enroute import settings that need to be changed?

[greasywheats]

Darn. Thanks Gerry! I saw something in one of the "similar threads" below about checking the tolerances in ACAD? The only tolerances I know are in the dimensioning toolbar and I don't think that would have any effect on actual drawing tolerances...Any idea where to check my "tolerances"?
Thanks again!

[greasywheats]

Gerry- Answered my question with some research that ACAD always uses maximum precision to save locations and sizes of objects drawn in ACAD.
Do you run Enroute yourself?
Thanks!

[ger21]

No, I don't use Enroute.
As I said, there's absolutely nothing wrong with the .dxf.
You're issue is 100% with the way that Enroute is importing it.

[victorofga]

autocad has no settings for tolerance.. like other programs does..

tolerance settings in autocad at dimesinal variables.. but that has no affect for the drawing actual tolerance

cam programs, and enroute has, but that tolerance settings for the toolpathgeneration..
curves that not described with arcs, those outputted as short line segments..

very roughly when you set tolerance it will makes a circle more and more polygon..
a rougher tolerance makes example a hexagon, while a finer tolerance makes 200 sided polygon to replacing a circle..

================================================== ===

another issue is the Bezier what used by enroute not same than the b spline used by autocad..
older autocad has no pdf poutput.. migthbe newer autocad has..

if you cant upgrade your autocad, it can be costly.. then draftsight what is free will export your dxf to pdf.. and that pdf already contan curves of autocad splines..

also inkscape can import dxf with splines and output eps with curves..

[greasywheats]

Yeah, I realize that now for sure. I am now wondering if anyone who uses Enroute may have this issue.
His second issue that is a problem is that for more complicated files with several different objects, including shapes with polylines and splines (as well as text boxes and dimensions, he is finding that upon import, nothing is showing up as visible in Enroute! This the second major problem that I need to research (now that I know that I habe him working through his import settings to fix the choppy curves - he is changing the default import precision from .01 to .001....we'll see if that fixes the choppy curves).
Thanks for the help!

[ger21]

Try exploding your dimensions first.
More than likely, text and splines are not going to work.

[greasywheats]

Do you think that having text and splines in the file would keep him from "seeing" other simpler objects in the same file (say a rectangle with filleted corners), or would just those 2 elements not show up?
Thanks!

[ger21]

No, just those two entities would not show up.
Is this an older version of Enroute, or a current version? I would expect a newer version to be better at importing .dxf files.

[greasywheats]

No, interestingly enough, this is Enroute V5. Previously, he had V4 and we did not have so many issues as we do now (curves were fine, importing much less hit or miss). Both machines (the earlier Multicam 1000) and the lastest Multicam 3000 probably came pre-loaded with Enroute, so maybe the V4 had its import settings etc better dialed in? We'll keep plugging....I feel like we have a couple good things figured out.
I am left with the task of converting all the Splines in my ACAD files to Polylines for Enroute to use (apparently a common issue). I am working in ACAD 2005. Is the wmfout/wmfin the best option? I don't know lisps and I need these splines to convert with 100% precision. Any links or advice?
Thanks again, Gerry.

[ger21]

Define 100% precision? Converting a spline to polyline will typically give you a polyline made up of straight segments.
The simplest way is to just save as v12 dxf.
I use a lisp program I've had for years which gives control over the # of segments.
Another option, which I've done on occasion, is to trace the spline with the polyline tool and the arc option, which gives you arcs instead of all the shirt, straight segments. It can be rather tedious, though, and can be tricky if you don't really know what you're doing.

[greasywheats]

Ugh. Well, if you can picture an 1950s or so era travel trailer (known colloqially as a Canned Ham, for the shape of a canned ham on its side), that is the shape that I am drawing in ACAD. The curve from the very top to the back and the curve from the very top to the front are not even elliptical arcs, they are made up of individually plotted points to make the special shape. I have already drawn this custom shape as a Spline in my files. Aside from the cnc routing of the sidewalls (what this whole exercise has been focused on), I also have the aluminum skin water-jet cut to that same profile. Not to mention that all the cabinets, etc are a tight fit to that profile. So changing the profile in these files creates a whole chain of headaches for me down the string...

Individual line segments would be a problem (similar to my existing choppy curves issue) as that profile needs to be very smooth. I think I can execute a basic Lisps (i have seen some instructions on the forum somewhere), but need to know that it will not deviate much from the current curve shape (say 1/32" or 1/64" tolerance).

Its crazy how I never had this problem with splines with my last CNC guy...gave him the files and it the product came back perfect! Man, I need my own machine ;(

[victorofga]

I made some tests..

true I made with draftsight due I have autocad2000 only..

first I drew a spline.. the ver12 dxf ascii resulted short segments..
the version 2004 dxf export resulted the original spline..

also exported as pdf and it contain the spline converted to Bezier..
true, segments are separated where spline controlpoints were..

also converted to eps with ac express..

[victorofga]

I just checked autodesk site, and 2004 dxf has groupcode for splines..

SPLINE [DXF - DXF Reference]

so from here, you can save from your autocad as dxf... it will contain all curve.. and convert either way with draftsight or inkscape to pdf - eps..

and that can be imported as curve into enroute..

[ger21]

Even straight segments shouldn't deviate much at all from the original spline.

If you can, try this.
draw a line at the end of the spline that's tangent to the line. Then, use the polyline tool, and start at the end of the line, and click on the end of the spline.
While still in the polyline command, type "a" and enter, to go into arc mode. Then use the nearest snap to snap points along the spline. This will give you a polyline that matches the spline. It may take some practice to get the hang of it. During the command, you can also type "u" and enter to undo individual points, if you need to back up a little, without having to start over.
When you finish, just delete the original tangent line, and trim the stating straight segment of the polyline.
You should be able to draw a polyline within .01 of the spline.