Hatch Island Detection not working

[jasminc08]

Hi all,

I recently just learned that there is an island detection option with Hatching polylines.

I have done a simple test of just drawing a big outer rectangle and a smaller rectangle inside.

Tried both 'Outer island detection' and 'Normal island detection'. Neither works. It still hatches the whole big rectangle, not detecting the smaller rectangle inside.

Additionally, I remember being able to see the hatch when I just hover my mouse inside the space of a polyline, however, I can't see this anymore and have to select the polyline.

I have also tried HPISLANDDETECTION set to '1'.

I am using AutoCAD 2025.

Thank you in advance for any help and suggestions.

[imadHabash]

Hi,

Would you please attache here the same CAD dwg file that you test?

[chriscowgill7373]

How are you selecting the objects to be hatched?  Can you provode the steps you are taking and what options you have selected for your hatch?

[jasminc08]

Hi,

I have now finally figured this out thanks.

I have attached the drawing. However, ideally, I would like to create an attribute to define the total area of just the shaded part, if this can be done. Previously, I would select object (polyline), however, of course this time there are technically two polylines.

Many thanks.

[jasminc08]

Hi,

I was typing out my step by step then realised what I was doing wrong! I was doing

hatch button/type hatch command > enter > automatically on select objects > set pattern to solid > set options set to normal island detection > press large rectangle > it fills  everything.

Now I realised I should also press the smaller rectangle after, and now it does what I want it to. Silly mistake.

However, would you happen to know how I can measure the total area of the now just shaded area, instead of looking at the Area of each rectangle in Properties section then subtracting the area of larger rectangle with the smaller rectangle?

Also ideally, I would like to create an attribute to define the total area of just the shaded part, if this can be done. Previously, I would select object (polyline), however, of course this time there are technically two polylines.

Many thanks.

[imadHabash · Accepted solution]

Hi,

@jasminc08 

Thanks for the CAD dwg file..
Click on below image to see how it works fine. Try to do it right and see if any changes.

[imadHabash · Accepted solution]

@jasminc08 

>> I would like to create an attribute to define the total area of just the shaded part

I suggest to try attached Lee Mac lisp code. Type A2F command after uploading the lisp. Click on below image 

         

Note: The text will change automatically if any hatch size changed. Just type Regen command after any changes.                                                                                        

[imadHabash · Accepted solution]

>> I remember being able to see the hatch when I just hover my mouse inside the space of a polyline

You may need to:

• Toggle Hardware acceleration On / OFF from Graphicsconfig command.
• Check in command line Gfxdx12 = 0 then Close and restart AutoCAD. If no difference, set back to 1.

[lauri_barnhart]

Hello, @jasminc08,

Did the information provided by @imadHabash help you and answer your question?

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Lauri | Community Manager