Transparency Masks and Patterns

[fgwebbjr]

Can I  create a pattern of random small blobs that I can use as a transperency mask?

Example I have a shape filled with a solid color or pattern, then I copy in place a duplicate of the shape and fill it with my blob pattern. I would like the blobs to act as a transparency mask to "cut  holes" in the original underlying shape. 

Or can I use a second fill on the original object that utilizes the blob pattern as a transparency mask?

Suggestions?

[Ton Frederiks · Accepted solution]

You could use a seperate object filled with your blobs above your other object.

Select both and choose Make Mask in the Transparency panel (play with the Clip and Invert Mask checkboxes for the correct effect).

[fgwebbjr]

Close. I can do that for each individual object. However when I tried to apply to all of the objects in the layer simultaneous I could not get it to work.

[Ton Frederiks · Accepted solution]

Group the objects first before applying the mask.

[fgwebbjr]

Thanks...for the advice I was able to achieve the effect I was look for.

[Ton Frederiks]

Good to hear it worked.

[c.pfaffenbichler]

[fgwebbjr]

I would like to see each individual circle within the pattern act as the mask ...not the entire rectangle containing the pattern.

[Doug A Roberts]

In that case tick 'Invert Mask'.

[Ton Frederiks]

You can also add a second fill to the object in the Appearance panel.

Give the top fill an opacity of 0%.

Select  Knockout group for the combined appearance.