Venn diagrams in Visio?

[Mike Carroll]

Logic texts use simple diagrams called Venn diagrams. They have
overlapping circles as components, with parts of the circles filled
in, to illustrate different relations between sets.

If I put two overlapping circles on a Visio diagram, I can fill in
both circles with the same pattern. This illustrates the union of two
sets.

To illustrate the intersection, I need to fill in just the area where
the two circles overlap. This area is not a separate Visio shape, so
I'm having trouble figuring out how to do this. I thought maybe I
could give complementary fills to the two circles somehow, so that the
fill would only be visible in the intersection, but haven't found
anything that works.

Anybody know a Visio trick to solve this problem?

Thanks.

Mike Carroll

 

[Geert Vancompernolle]

There's indeed a trick:

- Draw your ovals (Venn diagram symbols), the way they overlap like you want
them.
- Select both (or more) ovals
- Select Shape -> Operations -> Fragment

Result: you will have (in case of 2 ovals) 3 separate areas, that you can
for instance separately fill with a different color.

--Geert

 

[Geert Vancompernolle]

One remark:

The parts will be physically separated (hence 'fragment')... So, if you
select one of the items and move it, then the rest will not follow...

Hope this is what you were looking for. If not, others any idea?

--Geert

 

[Lori Pearce \(MSFT\)]

If you are using Visio 2002 or Visio 2003 you could also use fill
transparency to get an overlapping effect.

 

[Mike Carroll]

There's indeed a trick:

- Draw your ovals (Venn diagram symbols), the way they overlap like you want
them.
- Select both (or more) ovals
- Select Shape -> Operations -> Fragment

Result: you will have (in case of 2 ovals) 3 separate areas, that you can
for instance separately fill with a different color.

Hi Geert,

Hey, I had never heard of "Fragment" before. I tried it out and it
does just what I wanted. (I tried positioning an elipse over the
intersection, but that's a hack.) -- I'll make sure I fragment after
I've got everything else set up, so I don't have to worry about moving
around.

Thanks much for your help.

Mike Carroll

 

[John Marshall, MVP]

Sorry Lori, the overlapping colours tend to give a washed out effect. For
Venn diagrams the colour contrast is a lot stronger. For example, a yellow
circle overlapping a blue circle will have a green overlapping area. For the
current version of Visio, the overlap colour is dependant on which circle is
in front. (It's number 34 on the wish list.)

For now the fragmenting solution gives the best results.

John... Visio MVP

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