Contract selection

[Ferlin]

I have been fooling with circles - inspired by Marks Glass Button tutorial-
and I have noticed that when I select a circle and go to selection - modify - contract and then apply it, i start getting an octoganal [Stop sign] shape -rather than a smaller circle. I tried it with 10 pixels and tried it withe the anti- alias button on and then off, and that made no difference. Is this contract selection only for small modifications or is this not working right. If I go for a large pixel contract- the octagonal shape is completly obvious.

 

[Welles]

Ferlin,

I've run into the same issue and have learned not to depend on expand or contract in fairly small selections. What I've learned to do is draw out the smaller selection by using a combination of the elliptical marquee tool with the shift key held down to constrain the selection to a circle and, while doing the above, moving the circular marquee into place by additionally holding down the space bar which enables you to move the marquee around without changing the proportions.

I've never thought to ask why this occurs so I hope someone knows!

 

[Ferlin]

Thats what I was afraid of. It seems to work on very small changes, like taking out a soft edge or blur but for anything larger, and I don't mean much larger, I can't get it to work. I'll try you tip. Thanks

 

[davecross]

You can also try the Transform Selection command and drag a corner handle in or out (depending if you are contracting or expanding), while holding down Shift and Option (PC: Shift & Alt). The Option/Alt key makes the transformation happen from the center outwards so the selection doesn't move.

As you why it happens???????

 

[Ferlin]

thanks davecross,
That gets it. Locks right on it. I'll be using that from now on.

 

[Welles]

Yes! Thanks davecross it never dawned on me to do what you suggested and it's a much better technique.

Cheers!
Welles

 

[theKeeper]

Welles:

...moving the circular marquee into place by additionally holding down the space bar which enables you to move the marquee around without changing the proportions.

Just to clarify... holding the Space bar allows one to "pan" around the canvas area if they're zoomed in considerably, or the canvas is too large to fit the useable work area. You'll notice your cursor changes into an open hand.

As Dave mentioned... hold the Alt/Opt key along with the Shift key will force the marquee selection tools to a uniform shape which is created from the center outward.

 

[Welles]

Mark,

Sorry, my original comment was confusing. I meant to indicate that when you are drawing out a selection holding the shift key down of course constrains it to a circle in the case of the oval marquee shape or a square in the case of the rectangular marquee. If, while you are still holding down the mouse key during the drawing out of the marquee, you then hold down the space bar you can move the marquee around but the shape/size doesn't change. You can then let up on the space bar and continue drawing out the marquee. When I use marquee tools I always have one hand on the mouse or Wacom and the other spanning the shift key and space bar. In that way I can size and reposition the marquee with great accuracy and in one series of steps.

Damn! This explanation isn't much better, I'm afraid!

 

[theKeeper]

If, while you are still holding down the mouse key during the drawing out of the marquee, you then hold down the space bar you can move the marquee around but the shape/size doesn't change.

hahaha nono Welles NOW i see what you're were trying to explain. Makes more sense now.

Good stuff!

 

[wbiss]

[confused] Must be a PS "quirk" that the circle selection gets distorted when contracting this way...???

:\ Just thinking out loud...

[stuned] I searched the net and couldn't find anything on this phenomena.