Solidworks Spline tool not a smooth line when exported as 2D drawing

[North_roll]

Hello everyone

Have another question

but this one has been around for awhile, I looked on the Solidworks forums and this issue has been posted there a few times but with no resolution

You make a shape in a sketch with the spline tool
Then you export that to a drawing, the nice smooth line you had in the sketch is now a bunch of poly lines...lots of lines connected that resemble a smooth line but your smooth line is gone

I exported the drawing to a PDF. but it seems no matter how high you put your settings in image settings or the pdf save options...you cant get your smooth line back like it was in your sketch

If you extrude the drawing or sheet metal it...then you seem to keep your smooth lines of the spline tool...but if you just sketch then jump into a drawing with it...smooth lines are gone

Was wondering if anyone has a work around for this

I have a file attached as an example...if you zoom in a little on the curves youll see the lines...

The 2020 Solidworks is much better then the 2018 version I have tried, with 2018 you could see the lines plainly and did not have to zoom in...so things are getting better.


Thanks

Michael

[cwilliamrose]

If the spline was exported it may have been converted to polylines. There's a setting to control which type of entities are exported in a drawing, I think the option is to use Solidworks entities (instead of AutoCAD??). If not;

I played with a spline in SWx 2018. When you 'save as' a PDF there are few options for output quality and maxing those out (600dpi) still results in a segmented curve. I printed it to a PDF file (using PDF-XChange 3.0) at 2400dpi and it looks much smoother. So it looks to be a resolution limitation of the Save As PDF function in SWx. I notice arcs and circles do not have this same issue as they appear smooth even at 600dpi.

[North_roll]

If the spline was exported it may have been converted to polylines. There's a setting to control which type of entities are exported in a drawing, I think the option is to use Solidworks entities (instead of AutoCAD??). If not;

I played with a spline in SWx 2018. When you 'save as' a PDF there are few options for output quality and maxing those out (600dpi) still results in a segmented curve. I printed it to a PDF file (using PDF-XChange 3.0) at 2400dpi and it looks much smoother. So it looks to be a resolution limitation of the Save As PDF function in SWx. I notice arcs and circles do not have this same issue as they appear smooth even at 600dpi.

Thanks for taking the time to look at this for me

The spline you did looks great.

Did you put your sketch in a drawing then export to the PDF-Xchange or did you print to PDF while still in the sketch and open it in the PDF-XChange program..

Thanks
Michael

[cwilliamrose]

I drew the spline directly in a drawing (not a sketch) and printed it to PDF-EXchange.

[vondeliusc]

I investigated this yesterday and with nothing to add, I got a segmenty line in an extruded solid which carried through to the drawing. But with Bill's trick, putting the spline in the drawing, it comes out smooth for some reason, and I have my 'Options' smoothness cranked all the way up. Not sure what is happening. Saving as a pdf and printing to Acrobat as a pdf both wind up with segments when zoomed in. Saving it as a DXF and opening it in Adobe Illustrator it comes out smooth. Importing into
PlasmaCAM it has segments. It is below any tolerances in real life for me so the segments are negligible. FYI
-Christian

[2ndsegment]

Representing real numbers or transcendentals as "floating point" by TYPING in the language or mixed numbers as integers and rationals of very large word length is something that tries to make up for the computer fixed word length and thus no actual continuity in equations. I have Solidworks 2013 but so far have avoided getting the EAA version because earlier I once had Microsoft Visual Studio and as long as I had Basic and it's macros I could distribute my .exe's. As soon as I added a educational version of C++ all of my .exe's were blocked from distribution and after I finished the tutorials, the support files necessary to do the procedures practiced were deleted. I assume that NURBS are a type that uses large rationals in a data base form that is not a uniform grid for saving. For now I avoid splines as they fall apart when rotated as in a propeller--??? They aren't analytical but rather are a practical concept I saw used for making full size DC-10 wings using heavy hand weights with a right angle and tip and pointed "mouse tail" to load the acrylic physical splines to define the airfoil curve. (about 1969) Just before the Ozalid machines to reproduce huge rolls of blue print paper were closed down.

[North_roll]

spline tool issue resolved

[cwilliamrose]

I'm not sure they would consider this a problem. Drawings are typically not meant to be templates. There are a lot of potential inaccuracies introduced when you print something which is why drawings are meant to be read for their dimensional info and not scaled (measured) to obtain dimensions.

You can use printed drawings as templates for non-critical stuff like wing rib profiles to make wooden ribs and some plans do that rather than provide dimensions. Even pounding out aluminum ribs over hand made forms could be done this way. Anything considered critical should be done using better methods IMHO.

[North_roll]

Spline tool issue resolved..

[cwilliamrose]

I wish I knew. There are splines then there are splines. I don't know the math but some types are considered better than others for reasons I'm unlikely to ever understand. Maybe your current CAD tool uses a different type, maybe they optimized for printed output and SWx didn't bother because it's not mission critical. I do believe SWx was aimed at mechanical design and that means formal 2D drawings as part of the output, not templates. Can you make decent enough templates for making wood parts and tooling in SWx? Of course you can but getting bogged down in levels of printed accuracy that means nothing to the process you're using will only cause frustration. I have made templates for these types of parts and tools -- there are no drawbacks from my experience. Got a few bumps? That's what I use sandpaper for,,, really.

I have a question and I don't mean to sound like an ***hole, I'm just trying to understand the motivations. If you're happy with Fusion 360 why are you bothering with SWx? I'm happy enough with SWx after 20+ years that I feel no need to look elsewhere.

[2ndsegment]

Here is a site that shows how to make what they in marine call "ducks", though I alwys heard them referred to a "mice" to locate a spline for shapes much bigger than any ship's curve or French curve could follow. https://duckworksmagazine.com/06/howto/splineweights/index.htm This site shows them used to make guitar bodies. http://www.frets.com/FretsPages/Luthier/TipsTricks/DraftingWeights/draftweights.html Here is a more total form of history which includes the "ducks." http://www.alatown.com/spline-history-architecture/

[North_roll]

Spline tool issue resolved

[cwilliamrose]

I do much the same as do others. It 'works' for us. If you have specific information about why you feel SWx splines "do not work" (a very broad statement!) how about letting the rest of us in on it. If your comment is based solely on the printed output I have shown how to improve the output -- a solution you agreed looked good. So SWx splines are fine by your own admission and it's only a resolution issue using the SWx Save-as PDF. That is my take on this. You want better output, download and use a high res PDF printer. Problem solved (unless there's something you haven't mentioned).

[North_roll]

Spline tool issue resolved...

[cwilliamrose]

SWx can be quirky sometimes. The solution to the quirkiness is sometimes less than elegant but there's almost always a solution. It's not just splines, it can happen to almost any operation. Chamfers and fillets can behave oddly and the solution is usually to change to order they are created or separate them into several chamfer/fillet operations. Why does this happen? I don't know but it has been that way forever. Those commands work perfectly 99% of the time so I wouldn't say they are broken but they don't handle every conceivable situation in a straightforward way. In the developer's defense they can only test the normal stuff and then turn it over to beta testers to see what they find. That still doesn't cover all the possibilities because there are an infinite number of them.

As for my use of PDF-XChange, that dates back to the time when SWx didn't have a Save as PDF function. I still use it partly out of habit and partly due to the level of control it provides. But the only time I have ever used 2400 dpi output was the test I did for you. In my normal use the output defaults to 300dpi and that works fine for me, even when printing templates. The segmented curves don't vary more than a few thousands from nominal so they are small enough to ignore. Cutting and sanding the shape takes care of any smoothness issues the print may have had, at least in my experience.

When you generate a plot of the 23012 airfoil do you do the target (final) profile and then offset for the tooling? Are the splines fully defined (or fixed)? I wondered that about the sine wave example you linked to as well. If I was that user I'd try making a master sketch and doing the wave extrusions one or two at a time instead of all at once. They could be merged a few at a time once you did that. He/she could also try cutting those features into the part instead of adding them. Anyway, asking for too much at once can often be a problem in SWx for some reason.

My experience also shows that making a 'perfect' form block is only a starting point. Once the realities of spring-back and technique come into it there will be a development effort for each tool. The end result is often nothing like what you thought it would be to create the part........

[North_roll]

I'm very grateful for the time you took to get me to a solution....you're all volunteers here .. Doing it out of love and passion

I'm going to delete my posts on this issue ... I have a solution...and everyone here put in top notch effort to try to get things to work for me

consutants are $100s an hour and got the benefit here of your efforts..I appriciate your time

hope you have a good day

Michael