HATCH problem on very simple geometry...

[serge]

The two polylines cannot be hatched at the same time, neither by using 'Select Objects' nor 'Pick Points'. There are actually only two closed polylines in the drawing. No overlaps, no redundant vertices.
Thx.

[jreidKVSUZ]

Serge,

Wow. What a crazy thing to have happen. I even copied this into another drawing and still the same.

So I went to Hatch and looked for Options. My setting for ISLANDS was set to OUTER.

I changed it to NORMAL and bam!!!! Both sections hatched. Not sure what went on with this.

But this should work on your settings as well.

Hope this helps!!

Thanks, JRR!

[Kent1Cooper]

My first thought was the wrong PICKADD setting, but that's not it -- I can select both for other purposes [e.g. Copying, below].

Some weird stuff:

If I have picked [or picked inside] the smaller one, and then pick the larger one, it un-picks the smaller one, but not vice versa.  If I pick both, they both highlight in selection, but only the larger one gets Hatched.

As I try things, somehow the pattern name unaccountably gets changed from the initial SOLID to ANGLE.

I tried Copying them, and it worked right in the copies.  But in more tries [e.g. Copying in different directions] it did not.

BUT when I FLATTEN them, it works [for me, Acad2026].  I assume they differ by some really tiny amount in either elevation or extrusion direction.

[imadHabash]

Hi,

I didn't find any difficulty to hatch both polyline and with all island detection types. I suggest to check PICKADD (System Variable) = 2 

Click on below image...

Edit: No matter I select first the hatch process successfully done.

[jreidKVSUZ]

I tried all the PICKADD options and nothing worked. I run 2027 but just tried 2024. Same issue.

I also tried FLATTEN per Kent. Funny, it did not work. Even after I re-did the PEDIT them back to being closed.

Imad, what is your Hatch Setting for Island Detection?   Mine defaults to OUTER. If I change it to NORMAL per my discussion above it works great.

AI says NORMAL is the Best and Default Setting. Not on my computer. But will be soon!

The best, most versatile island detection setting for Hatch in AutoCAD is Normal (the default), which hatches between the outermost boundary and the first internal boundary, leaving inner holes unhatched. It balances detecting internal "islands" (holes) while ignoring "holes within holes" (like text inside a box).

To set the AutoCAD hatch island detection to "Normal" by default, set the HPISLANDDETECTIONMODE system variable to 0. This change ensures that AutoCAD treats internal closed areas as islands (unhatched) while hatching the main area, rather than defaulting to "Outer" or "Ignore" modes.

Method 1: Set System Variable (Fastest)
Type HPISLANDDETECTIONMODE in the command line and press Enter.
Type 0 (for Normal) and press Enter.
Note: The options are 0=Normal, 1=Outer, 2=Ignore.

Sorry, I keep adding. This video will explain what is happening with the OUTER section. 

https://youtu.be/ob7o6ybrz7Q?si=0wl9ZrvrbircrSyI

Thanks, JRR!

[imadHabash]

@jreidKVSUZ 

>> Imad, what is your Hatch Setting for Island Detection?

You can see it in Message #4

[paullimapa]

works as a single hatch object for both plines from 2021 up to at least 2023. But fails with the latest 2027 which tells me that most likely has to do with the change in the way hatches are generated with the latest releases.

[illusionistNUGXG]

At least, i can't find anything wrong with the polylines.

- the polylines are closed - that's a good start

I did EXPLODE them:

- all endpoints are on Z = 0 coordinates

- no zero length lines

- no lines drawn back and forth

- no (hundrets of) unneccesary splitted lines

The geometry is flawless. I could not replicate the problem, but i tried it using AutoCad Mechanical 2021.

[imadHabash]

@serge 

What is your CAD version?

I want to know if this hatch error is exclusive to the new versions or not?

[paullimapa]

Yep, problem does not occur in the older versions as I've also confirmed.

So only in the newer versions, does the problem occur.

It gets even more strange when I open the hatched object (created in the older versions) in the newer versions.

Though it recognizes the hatch as a single object, if I were to copy the smaller boundary pline and erase the copy, the smaller hatch pattern disappears too.

[jreidKVSUZ]

Paul,

I disagree, like I stated above " I run 2027 but just tried 2024. Same issue." I also later did 2026 and had same issue.

If I change the setting to Normal, all works great. If it stays on Outer (all 3's default setting), it does as Serge says his does.

But, with all that said. I tried Flatten once more.... it did not work on Serge's last week. But I tried it just now and Kent1Cooper was right. It worked.

Maybe I flubbed the remove hidden lines last week.

Thanks, JRR.

[paullimapa]

As I stated, the problem does not occur when I tested on 2021 to 2023.  Beyond that all bets are off.