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Polygonal Selection Tool Question


Wade71

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Hi, I just signed up to the forum so this is my first of many posts I guess!. My question is this, is it possible to change from "subtract from selection" to "add to selection" while the polygonal selection tool is active?. I've been using Photoshop for years and have no clue if its even possible?.

Thanks in advance for any replies.
 

IamSam

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Hell and welcome to PASG.

Just to clarify, are you talking about the Polygonal Lasso Tool?
 

IamSam

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If your answer is yes, you can easily change to "add to selection", "subtract from selection", or "intersect with selection" while you have an active selection. Haven't you tried it before?

Screen Shot 2017-09-01 at 11.07.51 PM.png
 

IamSam

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So how do you change between them while the Poly lasso tool is active?
Just click on the appropriate icon of choice. The only one you can't use is the "New Selection" icon.
 

Wade71

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Just click on the appropriate icon of choice. The only one you can't use is the "New Selection" icon.

No that doesn't work, the lasso is still attached to the mouse icon and the screen just scrollls up. I'll try and explain this in more detail. Say I start making a selection, tracing round an object, half way through I realise the selection is on "subtract" and not on "add to", I cant simply goto the menu bar and change it because I am half way through the selection, I also can't simply double left click to link up the selection because that would loose the tracing outline...
 

IamSam

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Say I start making a selection, tracing round an object, half way through I realise the selection is on "subtract" and not on "add to",
It makes no difference, just complete the selection.

The tool ONLY makes selections, the choices only matter if you intend on adding a new selection to an active selection.
 

Wade71

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It makes no difference, just complete the selection.

The tool ONLY makes selections, the choices only matter if you intend on adding a new selection to an active selection.

Another example: I make a selection of a round object, I notice the tool is still on "add to selection" after painstakingly tracing around a pattern I wished to cut from the middle of the round selection... I can't simply complete the selection to change it to subtract because the pattern is inside of the already selected area...
 
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Tony Bowman

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I don't think there is any way to do what you want. If you move the pointer to change the selection type part way through the selection, clicking the icon drops an anchor point underneath the icon, but doesn't activate the icon. The modifier keys also do not change the selection type. This can be frustrating when it happens, but each time it does happen, the learning point to check first will get stronger until it becomes a habit...
 

IamSam

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Another example: I make a selection of a round object, I notice the tool is still on "add to selection" after painstakingly tracing around a pattern I wished to cut from the middle of the round selection... I can't simply complete the selection to change it to subtract because the pattern is inside of the already selected area...
YES you can!

The Polygonal Lasso Tool does not care about about what you have "painstakingly" tried to select to remove form an image...............it only makes a selection no matter what the selection option is set to! The selection options only affect the active selection.

Lets say I'm about to make a selection with the Polygonal Lasso Tool. I have the selection option set to "subtract from selection". Before you start or while your in the process of making a selection, take a look at your cursor........please note that there is no minus sign on your cursor..............until you complete the selection..............then the minus sign will appear on the cursor. The selection options are only for and will only affect a completed active selection. No matter what the selection option is set to, it will not affect what you have "painstakingly" selected from an image or what you plan to do with the selection.

So here I have made a selection with the tools selection option set to "subtract from selection"
Screen Shot 2017-09-02 at 7.56.00 AM.png
I have made an ACTIVE selection around a round object.
Screen Shot 2017-09-02 at 8.17.21 AM.png

The selection option has made NO difference on the selection and what I can do with it.

But lets say I want to ADD to or SUBTRACT from my active selection.
Since I already have the selection option set to "subtract from selection"...........lets make a rectangular selection at the bottom......

Look...it subtracted from the center area of my active selection.
Screen Shot 2017-09-02 at 8.33.58 AM.png

Now lets try adding to the active selection.
I set my selection option to "add to selection", lets make another rectangular selection ant the bottom.

Look.........it added to the outside of my existing active selection.
Screen Shot 2017-09-02 at 8.37.35 AM.png

No matter what you have the selection option set to when you start making a selection or what you plan to do with the selection..........it doesn't matter unless your planning on altering the active selection.
 

IamSam

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Wade71 said:
I can't simply complete the selection to change it to subtract because the pattern is inside of the already selected area...
You can use the Polygonal Lasso Tool to make a selection within an active selection but only with the subtract modifier key or the "subtract from selection" selection option. If you have chosen "new selection", "add to selection", or "intersect with selection", it won't work.
 

Wade71

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You can use the Polygonal Lasso Tool to make a selection within an active selection but only with the subtract modifier key or the "subtract from selection" selection option. If you have chosen "new selection", "add to selection", or "intersect with selection", it won't work.

Hi Sam, thanks for taking the time to reply. I think the last sentence answered my question. I guess I just have to be more mindful in the future :cheesygrin:
 

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