My goal is to learn this kind of graphs that represent articulation points / biconnected components

enter image description here

and now I am trying to learn it

enter image description here

but every time I try to colour a half circle it colours the whole circle.

So how can I colour segments of circle like the above?


2 Answers 2


You need to split the circle into separate objects, then color the separate objects. You can't fill a circle with multiple colors other than using gradients or gradient meshes.

The easiest way to spit the circle and color, is to simply draw paths to divide the circle then use the Live Paint Tool to apply color to the separate areas. Expand the Live Paint Group and then delete any unwanted, leftover, pieces of the paths.


Assuming that you've drawn the circles and lines using the Ellipse and Line Segment tools (or the Pen, etc.), the colouring is relatively simple using the Live Paint Bucket or the Live Paint Selection Tool (Illustrator CS4 and newer). These tools require that the shapes and lines are not grouped or placed in different layers (if they are grouped, ungroup them first: select, then press Cmd-Shift-G).

  1. Select all shapes and lines that belong to the diagram using the normal Selection Tool, or press Cmd-A (Windows: CTRL-A).

  2. Click on the Live Paint Bucket in the tool palette. (It might be 'hidden' under the 'Shape Builder tool' – click on it and hold the mouse button down to access the hidden items. You can also have the group of tools open in a separate tool set.)

  3. Then move the mouse over the selected group of elements and click once to turn it into a Live Paint Group object. The tool will then interactively highlight in red the area that it recognises as an individual painting area.

  4. To select a colour, the Live Paint Bucket is connected to the Swatches palette. Use the arrow keys to navigate and choose a colour… Or mix your own colour in the Colour palette… When done, click in the area to fill it with the colour.

    It's also possible to use the Live Paint Selection Tool to just select an area within the elements by clicking it, and then paint it by clicking on the colour in the Swatches or Colour palette.

(Applying the Live Paint Bucket compounds the selected elements into one 'Live Paint Group'. Individual elements can still be selected using the Direct Selection tool, but to completely revert it into unpainted – e.g., to make structural changes – choose Object > Live Paint > Release.)

Illustrator CS5.1 colouring with Live Paint tools (Unfortunately the tool's mouse pointer isn't recorded correctly in this screenshot for some reason.)

  • I cannot still understand how to select an area like that?! It can only select one circle, not others, some odd setting on?
    – hhh
    Nov 8, 2013 at 18:59
  • Moved the question here, sorry cannot understand your answer good enough, too many buttons!
    – hhh
    Nov 8, 2013 at 19:05
  • 1
    I take it that you have found and chosen the Live Paint Bucket or the Live Paint Selection Tool. In your drawing, as shown in the second image, you need to make sure that the circles and lines are not grouped or placed in different layers. (If they are, ungroup them / move everything into one layer first.) Then select everything (Cmd-A) and move the mouse over where you want to start colouring.
    – TehMacDawg
    Nov 9, 2013 at 1:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.