How do I make consentric selections?

How do I make consentric selections?

Post by Aaron » Tue, 16 Apr 2002 08:57:50



Hi all.  I have a photo of an aircraft snapped in flight from another
aircraft.  I would like to enhance/fake the spinning prop effect.  To do
this, I need to make several oval selections.  The tip 5 inches of the prop
is painted white, then there is a one inch white strip below the white tip.
When a photo is taken with a shutter speed slow enough to create a full
rotation of the prop blurring' ( 1/60th shutter or slower depending on
engine rpm and number of prop blades) you get a sort of white disk with a
smaller white disk inside it representing the painted tip of the prop.  Also
these two disks are sharp edged, and are usually in some degree of
perspective.

I can't figure out a good way to generate these two disks (selections)
Anyone know how I could achieve this?
  ... Aaron

 
 
 

How do I make consentric selections?

Post by wnor » Tue, 16 Apr 2002 22:34:34


Is this what you want to do? On a new layer, draw your first oval with the
oval tool. Edit stroke it with white at 1 pixel. Control click on this layer
to select the first oval. Make a new layer. Go to Select | transform
selection and, holding down Shft and Alt keys drag out or in on one of the
corners. Hit Return. Edit stroke it with white or gray or whatever. Continue
doing this until you have as many rings as you want.


Quote:> Hi all.  I have a photo of an aircraft snapped in flight from another
> aircraft.  I would like to enhance/fake the spinning prop effect.  To do
> this, I need to make several oval selections.  The tip 5 inches of the
prop
> is painted white, then there is a one inch white strip below the white
tip.
> When a photo is taken with a shutter speed slow enough to create a full
> rotation of the prop blurring' ( 1/60th shutter or slower depending on
> engine rpm and number of prop blades) you get a sort of white disk with a
> smaller white disk inside it representing the painted tip of the prop.
Also
> these two disks are sharp edged, and are usually in some degree of
> perspective.

> I can't figure out a good way to generate these two disks (selections)
> Anyone know how I could achieve this?
>   ... Aaron


 
 
 

How do I make consentric selections?

Post by Aaron » Wed, 17 Apr 2002 22:23:22


Thanks, it worked perfectly!  ... Aaron


Quote:> Is this what you want to do? On a new layer, draw your first oval with the
> oval tool. Edit stroke it with white at 1 pixel. Control click on this
layer
> to select the first oval. Make a new layer. Go to Select | transform
> selection and, holding down Shft and Alt keys drag out or in on one of the
> corners. Hit Return. Edit stroke it with white or gray or whatever.
Continue
> doing this until you have as many rings as you want.