Is there a way to randomly fill a section of an image without the pattern getting cut off at the edges?

It’s tempting use Generative Fill nowadays.  I used the following text instruction to create the example below.  Note the typos, which did not appear to bother the Ai.  I tried Firefly at first, which failed badly.  The example was first try with Gemini 3 (I was using the release version, which does not have 3.1

‘fill the shape with skull and cossbones that are each approximately 10% the width of the shape. The skulls hould be white with black outlines.  None of the skulls should cut off by the outer edge of the shape.’

I modified the scripted fill to do this. This was before it had a UI, and I created my own. I would create a black and white layer with the shapes that I want. Then run tje script that would sample that layer and create a file with the tonal values. Then I would run the pattern fill and my script would put a pattern where there was black and not where there was white. This could also be done with normal scripting. Here a link to my script: uebelephoto.com/CS6_Fill.html

With a graphic like this (sharp edged) I think doing it in Illustrator would be preferable for the vector output – which may not be a meaningful concern for you in this case, though. 

In Photoshop I would recommend a Smart Object-approach. 

May I ask if the task is a frequent one? 

Hi ​@The Octopus Lady ,

Use Scatter Brush Instead of Pattern Fill.  Brushes do not tile, so no grid clipping occurs.

Steps

1.  Convert object to a brush: Edit → Define Brush Preset
2. Open Brush Settings
3. Enable: Shape Dynamics
   Scattering
   Angle Jitter
   Spacing
4. Paint inside selection

Let us know how you get along