In Illustrator, if you want to fill in areas surrounded by multiple line segments, you can first select all the line segments and use Live Paint Bucket (K) to fill the color. However, if you want to change the opacity of the area, you may find the borders also become transparent, like this:

My question is, is there any way to avoid the border changing its transparency when we change the transparency of its internal area?

Note: there are 3 line segments, with endpoints connected. An extended question, what if one of the line is dashed? This question originally comes from the fact that I want to fill the triangles as the bottom figure shows.

enter image description here

enter image description here

  • After you changed the Question can I ask you to add the screenshot where all shapes are selected?
    – Ilan
    Apr 23, 2014 at 14:02
  • Now, the task looks different from the original one. If all the lines are different objects you can fill the gapes by Hiding those which are inside the resulting outline. Probably, if you place the Layer Panel Screenshot we could help you more. Also, dashed lines - are they expanded or not?
    – Ilan
    Apr 23, 2014 at 14:14

1 Answer 1


Try to use Appearance panel:

enter image description here

to change the stroke opacity:

enter image description here

And change the colors independently.

Also, you can expand the shape and operate stroke shape and a fill shapes as separate objects.

  • Do I need to join all the line segments before the operation you proposed?
    – C. Wang
    Apr 23, 2014 at 13:52
  • From your picture it looks like 1 object: grey stroke and bluish fill. If it is not - I suggest you to re-create it by using pen tool or polygon tool. If there are 3 lines, thus them all are separate objects - in such a situation we need to see how the shapes are built (anchor points), cause paint should not affect them.
    – Ilan
    Apr 23, 2014 at 13:56
  • The shape was originally built by 3 line segments, connected at the their endpoints. What I did was first join them, and then adjust the filling color as you showed to me. However, I found another case, if one of the line segments was dashed, the join operation would cause all of them becoming dashed, which is not my purpose. So I'm wondering what is the correct operation when facing the shape built by separate line segments? Many thanks!
    – C. Wang
    Apr 23, 2014 at 14:03
  • I suggest to place a separate question with all the data provided as is - now I cannot realise in which step to perform the corrections.
    – Ilan
    Apr 23, 2014 at 14:06
  • I have placed a separate question here graphicdesign.stackexchange.com/questions/30054/… Welcome!
    – C. Wang
    Apr 23, 2014 at 14:18

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