Is there a way...

Is there a way in the paint section of surveyor to blur the area covered by the cursor circle? I recall a few years ago there was a way to do it, but i can't remember what the key strokes are that allowed me to do it. It was a really handy feature for simulating movement for rivers.

Hold down either the [ or ] key when applying the texture which rotates and blurs it, also useful for removing or making less obvious tiling patterns in the texture.

That's it....Thanks!