topic Converting 2D Polylines to surfaces - Retaining verticies along edges in AutoCAD Forum

Converting 2D Polylines to surfaces - Retaining verticies along edges

gobc — Tue, 01 Dec 2015 21:44:59 GMT

Apologies if this is a double post. This forum is giving me problems as well as the software.

I've recently upgraded from AutoCAD 2016 from 2008. When I use "convtosurface" on a 2D polyline the resulting surfaces no longer has verticies along straight edges along the surface's perimiter. This happens most of the time but not always. Is there a setting or a command I can use such that verticies on straight edges are retained when turned into a planar surface? This is very important to my work flow, and I'm really hoping for a solution.

I've attached a test file. Try using "convtosurface" on these polylines, and you'll see 1 of them retains it's verticies, the other two don't. Again, why is this, and how can I for the system to retain all verticies?

Here is an attempt of a screenshot to illustrate my point, but I"m not sure if it will work on this forum. And since, I can't edit a post, if it doesn't post, well I did my best.

[URL=http://s103.photobucket.com/user/Gobc12/media/SurfaceVertex_zpsgmi8nfxt.png.html][IMG]http://i103.photobucket.com/albums/m138/Gobc12/SurfaceVertex_zpsgmi8nfxt.png[/IMG][/URL]

http://i103.photobucket.com/albums/m138/Gobc12/SurfaceVertex_zpsgmi8nfxt.png

http://s103.photobucket.com/user/Gobc12/media/SurfaceVertex_zpsgmi8nfxt.png.html

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

gobc — Fri, 04 Dec 2015 17:46:55 GMT

For the love of god, can someone please answere this?

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

Patchy — Fri, 04 Dec 2015 18:12:02 GMT

DELOBJ is it different?

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

gobc — Fri, 04 Dec 2015 18:22:36 GMT

No. I have DELOBJ set to 2.

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

Patchy — Fri, 04 Dec 2015 18:39:16 GMT

Maybe the surface is merged, in 2008 there wasn't an option for it.

http://help.autodesk.com/view/ACD/2016/ENU/?guid=GUID-7AF911DF-986F-4897-8651-921BE8710B14

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

gobc — Fri, 04 Dec 2015 18:49:10 GMT

I played with this variable and still had no luck. I created 4 identical polylines, and converted them into a surface with "convtosurface", changing SMOOTHMESHCOVERT each time. The resulting 4 surfaces were all identical.

I was playing around this morning, and found randomly some polylines when converted to a surface would retain vertices, some would be merged. I couldn't finy any distingishing factors that attributed to this difference in behavior.

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

Patchy — Fri, 04 Dec 2015 19:04:28 GMT

I saw one polyline has a zero length in it ( when exploded to lines) would that make any different or not.

I don't have 2016 to give it a test.

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

gobc — Fri, 04 Dec 2015 19:17:42 GMT

It's a messed up problem. Its a very neesh thing. I appreciate your replies though. I have a few ideas I want to try. I might wright a macro that will take every polyline, explode it, then use those objects to create a region. If the region that is created has retained the outer verticies, then I can export those. If all else fails, I can install AutoCAD 2008 and use it for this one specific task. Still, weired and frustrating problem.

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

JDMather — Fri, 04 Dec 2015 19:33:42 GMT

I don't understand the problem.

Is there a reason you are using bits-and-pieces rather than Rectangles?

What is the end-game design intent?

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

gobc — Fri, 04 Dec 2015 19:40:54 GMT

Yes, there is a very important reason I'm doing this. I use AutoCAD to model FEA models of ship structures. If too surfaces of difference sizes meet, there needs to be a vertex on the edge of the larger surface where the smaller one meets it. This ensures that when the surfaces are meshed, a congruent mesh forms. By losing that verticies along a straight edge when a polyline is turned into a surface, my entire workflow just went to hell.

This sort of thing is very typical of software developers. They are always making asusmptions on how commands should work. And it always upsets people. The correct approach is to give the user a choice, rather than asuming what the user wants. I understand this this behavior is very counter intuitive, but from a perspective of the developer, you can never know how your customer is going to use your product. Which is why you should never assume anything. Develops must always give the user a choice, when a decision needs to be made.

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

dbroad — Fri, 04 Dec 2015 22:49:56 GMT

I don't know whether this matters or helps but those are the most messed up polylines I've ever seen. Try pedit on one of the and use the edit vertex option. On some of the polylines the vertex markers are off screen during the edit process.

Once I exploded the polylines, got rid of the zero length lines and rebuilt them, the performed consistently, keeping the additional verticies.

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

gobc — Fri, 04 Dec 2015 22:59:19 GMT

That is weired. I have no explanation for that. Good observation though. I did try flattening them, but that didn't help. The vertex indicators were still off the polylines.

Re: Converting 2D Polylines to surfaces - Retaining verticies along edges

dbroad — Sat, 05 Dec 2015 15:06:07 GMT

Don't flatten. Explode and pedit them back together but don't include the zero length lines.