How to randomly distribute objects only in selected area?

Question

Imagine you wanted to design a glass of soda. First you create a glass:

^{It's, in fact, a beaker - but that doesn't matter}

Now you copy the object, make it smaller, black and delete the stroke. Then to try to center it in beaker:

Finally, you want some pretty bubbles. How can I randomly distribute them in the brown area, besides copy pasting (which sucks for complicated shapes)?

Answer 1

Let's get a try...

You can create your bubble (sorry, not so pretty):

With the bubble selected, press the spray tool (see also here):

You can tweak a bit with the tool options until the object are placed according to your wishes:

Now, you can simply keep pressed your left mouse button down and place the bubbles while moving the mouse:

With a littler starting bubble and different spray settings:

Answer 2

You can use Randomize centers in both dimensions button under Rearrange in the Align and Distribute dialog.

1. Select all the objects you want to randomize, then hold down the Shift key and make a single click on the encapsulator object.
2. Open the Align and Distribute dialog via Objects → Align and Distribute menu item (or press Ctrl‌‌+Shift+A).
3. Under Align, select Last selected in the Relative to drop down list.
4. Under Rearrange, click Randomize centers in both dimensions button.

Sources:

• Alignment and Distribution of Objects — A Guide to Inkscape
• Align and Distribute — Inkscape — FLOSS Manuals