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Dana W

What comes out of Adobe Illustrator?

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Dana W

Yesterday, I had the misfortune of having to trace closed polylines over a couple of thousand spline like wavy lines from an Adobe Illustrator generated (vector) *.dwg file. These lines appeared to have a random mix of curves and straight segments, with many sharp corners at the segment ends, rather than tangential transitions like a spline, and even then, when selected came up in properties as "Spline". They didn't seem to have the same response to osnaps as the typical AutoCAD spline does. Of course, AutoCAD splines are not all that osnap friendly either.

 

What's more, it was very difficult to get the polylines (arc) to wrap around the strange Illustrator curves I was tracing. AutoCAD polyline will somehow sense that you are tracing over an existing pattern, and 'follow' the 'path' pretty well even predicting that it is ok to deviate a little to one side or the other to match up to a tangent on the next arc. In the illustrator generated drawing, it seemed like there were invisible gaps in the 'splines' even though there was a visible path to follow. These gaps, or more probably sharp transitions in vector, caused the polyline arcs to pop off to the wrong side and create huge arcs the size of the moon. This meant I would have to esc, turn on osnap, and start again from that point, the object being to surround existing 'plain spline' geometry with closed polyline shapes for a cnc machine to cut by.

 

I was wondering of anyone had a better approach to this sort of problem. As far as I know, I was re-inventing the wheel, and not realizing that my new wheels were all square and totally inefficient.

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eldon

Whenever I have to trace over wriggly lines, I use a polyline, but with straight sections whilst tracing. At the end, I use the "Fit Curve" option in Pedit. It saves having to create curves as you go.

 

Does the Command Sketch exist anymore? With the system variable SKPOLY set to one, a polyline is created just by moving the mouse along the curve - no picking points as you go, but you need a steady hand!

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Cad64

That's the problem with these raster to vector programs. They only interpret what they see on the image, so you can get some really funky results from the vector output. However, I've had pretty good luck with Illustrator in generating relatively clean geometry. There is always a lot of cleanup work to be done on the vector files, but I never had problems like what you are experiencing. Are you sure your file was created with Illustrator and not one of those other raster to vector programs?

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f700es

Probably drawn with Illustrators Pen tool.

Newer versions of Acad handle splines better.

 

In Illustrator CS5

Screenshot_2.jpg

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f700es

Or maybe a PDF exported to a DWG?

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JD Mather
.... surround existing 'plain spline' geometry with closed polyline shapes for a cnc machine to cut by.

 

You can convert spline directly into machine g-code friendly arcs somehow (I have to find my notes).

Involves something like Flatten, maybe Overkill and Explode. There is something to control the resolution too (number/size of arcs created) but I forget all the steps. I think they also added a more direct way sometime around 2010 - I have to run now, but I'll check my notes later.

 

But if you are using an imported spline... ....well I don't know what kind of results you will get.

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Dana W
Or maybe a PDF exported to a DWG?
Nope, it was a dwg file straight out of Illustrator, at least according to what my client told me. I would post the original, but it is recognizably proprietary without a title block, and the project is ongoing. It is a 77.5" wide by 34" tall frame to be water jet cut and then hammered to look like wrought iron. Basically it was like drawing a 6 and a half foot length of hedgerow, complete with leaves, bugs and birds nests.

 

Fitcurve? I don't remember seeing that option, but then I was using only arcs for 99 percent of the time. I did see decurve. I thought it was just something they left out of LT.

 

I will have to play with pedit some more. If I could have drawn the whole thing with straight pline segments it would have cut the time by two thirds, at least. I also had to eyeball the whole thing, the osnaps were not in the right places.

 

Oh, forgot to mention some stuff that might be important. The drawing was in 2010 format and then had to be converted back to 2007 via TrueView so I could open it in LT 2009. It came in the email unconverted the first time, at 843 kb file size. I could have converted it, but the client insisted on doing it. When it was again mailed to me, it was 2.3 mb with nothing to purge. Then it hogged down my AutoCAD and aborted it before I could do any clean-up. I did not get any error messages. The program window simply grayed out, and after about 5 minutes of waiting for a response, it simply dematerialized. When I re-opened and did a Recover, it was again around 800 kb.

 

I did not mention that stuff before because I was experiencing the same difficulties prior to the drawing blowing up. I don't think it was the conversion, but who knows.

 

My client seems a bit crabby about how long it took to draw. I had to turn it around in 24 hours. Turns out, I used all but 4 of those 24 to draw it, from 7:30 PM on Tuesday, to 7:30 PM on Wednesday. I stopped to take a nap at 6:30 AM on Wednesday for 4 hours and then went back to it.:sweat::sleeping:

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Dana W
Probably drawn with Illustrators Pen tool.

Newer versions of Acad handle splines better.

 

In Illustrator CS5

[ATTACH=CONFIG]43715[/ATTACH]

Quite likely. It did look decidedly hand drawn.

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Dana W

Thanks JD and Eldon, but in AutoCAD LT, sketch, flatten, and overkill, don't exist. On my budget, they ain't likely to in the near future neither.

 

I'll have to figure a way of living with this sort of stuff, because my new client, a contractor who is a misc. ornamental metals shop deals with a designer quite a lot who insists on using Adobe Illustrator to create drawings.

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JD Mather
..... ornamental metals shop deals with a designer quite a lot who insists on using Adobe Illustrator to create drawings.

 

They are giving you artwork - I would use it for nothing more than reference. I probably wouldn't even snap to it. Freeze the layer and then on new layer layout my lines and arcs to closely reproduce the general geometry. They will never know the difference.

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Dana W
Whenever I have to trace over wriggly lines, I use a polyline, but with straight

sections whilst tracing. At the end, I use the "Fit Curve" option in Pedit. It

saves having to create curves as you go.

 

Well, now. I have some pie to eat, crow flavored. I found the Fit Curve, actually listed as Fit, in the Polyline Edit dropdown list. I didn't know that is what you were referring to, Eldon. I did try it a couple of times yesterday while I was working, but had no success because I was not using straight lines at the time. I played with it a little bit ago and found that I like it a lot. It would have saved me hours if I had known how to use it. After all these years, one can still find new stuff to learn. I especially like the Quadratic option. Once you have turned the polylines to arcs with Fit, then you can quadratic 'em, and it refines the arcs to nearly a perfect fit. One thing though, the Fit option leaves a hugeomongous amount of grips on the polyline arcs, Boy Wowie. Do all those points affect the cnc machine any?

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Dana W
They are giving you artwork - I would use it for nothing more than reference. I probably wouldn't even snap to it. Freeze the layer and then on new layer layout my lines and arcs to closely reproduce the general geometry. They will never know the difference.
That is precisely what I did. 7,358 control points later, it was done.

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f700es
They are giving you artwork - I would use it for nothing more than reference. I probably wouldn't even snap to it. Freeze the layer and then on new layer layout my lines and arcs to closely reproduce the general geometry. They will never know the difference.

 

+100 on this!!!

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Dana W
+100 on this!!!
Exactly, but locking works better, Then I could still see the squiggles, only dimmer.;)

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bbankston

It's too bad you can't share the file, Dana W. I've worked with AI and AutoCAD numerous times and have only found that CAD doesn't care much for the way AI creates font outlines. There's a thread somewhere on this site where I shared my DXF (originally AI) drawing of Calvin & Hobbes. It turned out really good using AutoCAD as a viewer. I'll see if I can find that file for you.

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Dana W
That's pretty cool. I copied it to my computer. I swear I won't claim I did it.:lol:

 

I was going to upload my squiggly drawing final result, minus the logo inside of it, but now I have an error in it. AutoCAD LT 2009 is telling me it can't open the drawing because it was created in a newer version. This is simply not the case. My program was the last one to save it. I have had this problem a couple of years ago with another drawing but never managed to fix it. Now I have two of them to fix.

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Dana W
It's too bad you can't share the file, Dana W. I've worked with AI and AutoCAD numerous times and have only found that CAD doesn't care much for the way AI creates font outlines. There's a thread somewhere on this site where I shared my DXF (originally AI) drawing of Calvin & Hobbes. It turned out really good using AutoCAD as a viewer. I'll see if I can find that file for you.
Luckilly, no fonts in the drawing. If they send me vectorized fonts I will send 'em back.

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