Separating solid hatch causes a problem

[Anonymous]

Hi,

Can anyone help with this please? I have created some separated solid hatch objects which are bounded by closed polylines that contain islands. One of the islands within one of the polylines is infilled with part of the hatch of a neighbouring polyline! See the attached drawing for details.

If I create one hatch object for all the polylines, the hatching is fine and the island is not infilled. But if I then separate the hatch I get the same problem described above.

Any ideas how I can stop this happening?

I am using AutoCAD 2016.

Thanks in advance!

Charles

[parkr4st · Accepted solution]

in your separated hatches, select the lower right hatched area, notice the hatch includes the small island circle in the area to the left.

erase the hatch from those areas and hatch the right area again,

in my 2017 the circle does not hatch again as part of the right area.

[Anonymous]

Thanks for taking a look - you are absolutely right.

I guess the obvious next question is: how do I avoid having to rehatch this problem polyline? Is there something wrong with the original polylines that caused the problem in the first place?

This has all come about because I am writing a lisp routine which hatches all the polylines on a certain layer, measures the separate hatch areas and quotes them on the drawing. I don't want to have to go back and check whether the hatch command worked correctly, and if necessary rehatch some of the objects manually and adjust the area figures. It would be nice to know how to avoid the problem occurring.

Any further help gratefully appreciated!

[Anonymous]

Following on from my previous posts, some testing has revealed that rotating the polylines and repeating the exercise produces some different results - i.e. when separated the hatches are now showing correctly (see the attachment). Although if the polylines are rotated by 90 degrees from their original position, the problem persists!

Does that provide a clue to the problem? Or does it just prove that this is one of AutoCAD's little quirks?

Any thoughts welcome!

[Patchy]

Try this, it doesn't do it for me.

[Anonymous]

Patchy - thanks for looking.

I tried your suggestion but still get the same problem when the hatch is separated. Which version of AutoCAD are you using? I am using AutoCAD 2016 & a colleague is using AutoCAD 2014, the problem occurs on both versions. Don't know if that makes a difference?

[Patchy]

2008

Probably a glitch in newer versions but no one caught it.

[Anonymous]

Hopefully someone with a newer version will be able to provide an answer to that thought.......or better still a workaround to the original problem.........

[john.vellek]

Hi @Anonymous,

I tried hatching in all angles and it performed properly in all cases. AutoCAD 2017. Hmmmm

[Anonymous]

John - thanks for the interesting test result. Are you able to repeat your test in AutoCAD 2016 and get the same result as I originally did?

[john.vellek]

Hi @Anonymous,

I tried this in AutoCAD 2016 and still had the hatches turn out properly. My HPGAPTOLERANCE is set to 0 as well.

[Anonymous]

Interesting! I also have HPGAPTOLERANCE set to 0. What other system variables could be making a difference?

[john.vellek]

Hi @Anonymous,

I wonder if it has anything to do with Hardware Acceleration....can you try toggling it off to see if it behaves differently? (GRAPHICSCONFIG)

[Anonymous]

Thanks for the suggestion - unfortunately the result was the same when I turned hardware acceleration off.

If you have any more thoughts please let me know!

[john.vellek]

HI @Anonymous,

Are you seeing this issue in only this one drawing file or others too? I still can't duplicate the problem. I even played with Draw Order a bit but since I can't get it to fail I am at a bit of a loss.

Does the Boundary command work any differently than your Hatch?

You might perform a Reset Settings to Default or even creating a brand new user account (full admin) to see if the problem persists.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[Anonymous]

Hello,

After trying numerous things and testing the sample file I came to the conclusion there was nothing wrong with the data within this file as it is possible to reproduce the same issue in a new drawing with objects drawn by myself. The issue lays within the Hatch command itself, using "Separate Hatches" or "Create Separate Hatches" and its "Ray Casting" algorithm. Please see attached SEPARATE HATCH PROB.DWG:

We have informed Autodesk Technical Support and await their response.

[Anonymous]

Thanks to those concerned for continuing to look into this problem.

The most recent post was particularly interesting since 1) it proves I am not going mad after all, and 2) the problem can be reproduced in a completely different drawing. The explanation in the accompanying drawing was very helpful, and I have been able to repeat the logic in a further drawing - thank you for thinking this one through.

Autodesk's response is awaited!

[parkr4st]

I tried the new dwg in 2015  and 2017 and it does not behave as you describe in either version. The hatch always was drawn as per the hatch settings. I never installed 2016 as it was full of problems such as this.  Perhaps install 2017 trial and try it?

Happy Holidays to all

Dave

[Anonymous]

AutoCAD 2017 is my next move - but it will have to wait until after Christmas. Fingers crossed it will solve the problem, although a shame the problem exists in the first place. Even more of a shame that it can't always be replicated easily!

Merry Christmas!

[Anonymous]

Hello Again,

I tried this is in both 2015 and 2017 with identical results.

Still awaiting response from Autodesk.

Merry Christmas and Happy New Year.