topic Re: Arcs not joined properly in AutoCAD Forum

Arcs not joined properly

infoJV782 — Tue, 29 Sep 2020 14:29:45 GMT

Hello!

I'm quite new to AutoCAD and recently i came across an odd problem. I don't know if it's because i've used a tool the wrong way or if it's some kind of bug.

I drew shapes using Arc and line tools, then joined them together with JOIN. All looks normal in modelspace but then i created a viewport in paperspace and the lines have gaps in them and doesn't look properly joined.

After some googling i tried joining them using PEDIT instead, but it still looks the same in paperspace viewport.

I also tried to use FLATTEN to make sure all the lines are on the same elevationplane.

The weird thing is that i tried pasting the lines into a new file (same template) and the problem was gone, no gaps or overlapping lines.

Im using AutoCAD 2021 on windows 10.

Re: Arcs not joined properly

ChicagoLooper — Tue, 29 Sep 2020 14:36:11 GMT

I see no gaps. I cannot detect any gaps. Can you upload the offending dwg file with the gaps so an evaluation can be made?

Re: Arcs not joined properly

vinodkl — Tue, 29 Sep 2020 14:43:18 GMT

Hi,

I could see that the problem is with the distance of the objects from the origin.

Here is the X, Y & Z values of the farthest objects in the drawing: ID Specify point: X = 123988.453 Y = 6605486.392 Z = 0.000

Try moving the object close to the origin and the problem would disappear.

You would see problems like these when objects are too far from the origin and AutoCAD is not designed to work well with objects such far away🙂

Re: Arcs not joined properly

infoJV782 — Tue, 29 Sep 2020 14:49:15 GMT

Unfortunatley i can't move the objects closer to origin because i'm working within a coordinatesystem, i need my lines to be where they are. But that explains why the problem disappeared when i pasted it into a new file, because i pasted it closer to origin. Thank you for your help!

Re: Arcs not joined properly

ВeekeeCZ — Tue, 29 Sep 2020 14:59:55 GMT

That's just a graphic issue - you can turn off the graphics acceleration to suppress the issue... but better don't do it, rather get used to it. You won't see it on paper.

This issue appears more often when you far from the 0,0 point of the coordinates system. Also if you split the screen into 2 or more VPorts.

BTW it does not really matter whether you connect these with PEDIT or JOIN. Only if you're joining two arcs with the same radius, it behaves differently.

Re: Arcs not joined properly

ChicagoLooper — Tue, 29 Sep 2020 15:13:17 GMT

So you can see gaps while viewing the lines and arcs while on a layout tab, correct?

What happens when you go to print preview? Are the gaps visible?

Re: Arcs not joined properly

vinodkl — Wed, 30 Sep 2020 04:59:31 GMT

Hi @infoJV782

@infoJV782 wrote:
Unfortunatley i can't move the objects closer to origin because i'm working within a coordinatesystem, i need my lines to be where they are.

In that case, AutoCAD is not suitable to work with large coordinates. You can try using CIVIL 3D or MAP 3D.

Though the plines and arcs appear to be not joined in the layout, they print very well. So that should not cause any trouble except they look broken in layout🙂

Re: Arcs not joined properly

infoJV782 — Wed, 30 Sep 2020 06:10:34 GMT

@ВeekeeCZ , @ChicagoLooper , @vinodkl

Thank you all for your help, i understand the problem now and can work around it.

The lines look fine when previewing/plotting, the problem is only visible in paperspace viewports. I'm just so used to having what you see on screen be what it looks like plotted that i didn't even think to preview the drawing.

Re: Arcs not joined properly

illusionistNUGXG — Wed, 30 Sep 2020 14:33:09 GMT

I've seen this issue in one of my drawings, even without being far away from 0,0 coordinates.

There are 2 more causes for this behaviour:

1. AutoCAD is drawing segments of polylines as single objects - for performance reasons:

Polylines can have a lot of segments - therefore it's faster (for AutoCAD) to deal only with those inside the viewport.

2. AutoCAD can't draw arcs (and circles). Regular polygons are drawn, to pretend to be arcs and circles. (a regular polygon with > 200 lines looks like a smooth circle)

...but some parts of the polylines have a huge radius (over 800 units in this case). These arc-segments have their centre far off the viewport - If the amount of lines drawn (by AutoCAD for performance) is to low, these segments look disjoined.

Sometimes REGENALL can help temporarily, but didn't have an effect testing on this file.

And of course, @vinodkl is right with the coordinates: being far off from those enhances the problem significantly.

Re: Arcs not joined properly

ВeekeeCZ — Wed, 30 Sep 2020 15:00:20 GMT

@vinodkl wrote:

In that case, AutoCAD is not suitable to work with large coordinates. You can try using CIVIL 3D or MAP 3D.

...

I would not say that. AutoCAD is very good in large coordinates but it has its flaws. As same as other softwares. And C3D/MAP isn't any better. In fact, this particular issue with gaps in geometry appears much often in C3D then ACAD. It's because C3D objects are much more complex, basically all are blocks (often in blocks in another blocks...), all in large coords). Then even a small inaccurate is multiplied.

I rarely see this issue in ACAD. But in C3D is on daily bases. Also the C3D's "bad" drawing exported to ACAD is good (export essentially explodes all blocks).

Re: Arcs not joined properly

dsulz — Tue, 07 Feb 2023 21:31:25 GMT

The best way to get rid of the disjointed lines/arcs or line and arcs not connecting is to turn off the Hardware Acceleration. For whatever reason the Hardware Acceleration causes more problems by being on, and it slows down your drawings, or rather your machine.

I work in Civil3d and have no issues with disjointed lines when I'm modeling or drawing lines in the real world coordinates. Even when I used Autocad to draw in real world coordinates I never had disjointed lines. Hardware acceleration is not a good thing and I would recommend turning it off.

Re: Arcs not joined properly

daa — Mon, 01 May 2023 04:43:38 GMT

I just resolved the disjoint nature of elements not connecting in model space by adjusting the 2D display settings of the hardware acceleration from Advanced to Intermediate. All is now good.