View Full Version : Lasso tools in PSCS
01-20-2005, 01:34 PM
Could somebody please explain to me the difference beween the lasso tools (Lasso, Polygonal, Magnetic) and under what circumstance I should use each one? Is one better than the others?
If I wanted to extract something from a picture, which one would I use?
01-20-2005, 02:12 PM
Well the magnetic lasso detects the difference in color or when something stops and another things starts...it is really good to use if you have a subject on a solid bkgrnd and you can just run it around the outside of the subject. you can obviously use it in other situations and tweak the selection using the other lasso tools. it does any shape but it picks points and snaps to the object.
The lasso tool makes a slection of where ever your mouse goes...circles swiggles etc. this is the one that i use most often. I feel that I have a pretty steady hand and I just go around the object/person i'm extracting. This is good to use also in tweaking a selection made by the magnetic lasso.
The polygonal lasso works in strait lines & points...so for extraction..it might be the least desireable selection tool from those three.
Are you familiar with the options under these?? the add to selection subtract from selection, new selection??? using the add to selection or subtract from selection it really makes those 3 tools work well with each other.
Great explanation, Liz
My fave for extracting is the magnetic lasso because I can't hol dthe mouse button down long enough on the regular lasso. and sometimes when I'm zoomed in so close I have to unclick to move to the next part and it closes itself wrong, and then I have to eitehr undo all my work, or fix up the messy part. Also, if I try to just scroll by pusing th elasso off the screen, it will suddenly JUMP way too far, causing more messy stuff. Now, I learned to do it in sections, but THEN I found the magnetic lasso, LOL! ymmv, everyone has his own preference
Check out Lauren's tutorial on Depth of Field, she extracts an image of her son. She uses the lasso or mag lasso, then uses the Quick Mask mode to clean it up with a brush. That's my FAVE way to extract. YOu can also use the Extract filter. Just make sure you use a small brush on parts where you want a harder edge, and a large brush for softer edges like hair. Takes practice, maybe you've seen that tutorial too, with the rose image
I love polygonal mostly for selecting things that the rect marquee won't fit around, on a transparent background like breaking apart a PNG alpha, or separating parts of a layer to copy to a new layer. Faster than the lasso.
I don't use the Lasso much, for tearing and similar jagged edges, and occasionally for something else. If it needs to be exact, I use the mag lasso, if it doesn't then I use the poly lasso
Just grab one and start clicking. See what they do, see which YOU like the best
01-20-2005, 10:54 PM
you got 2 great answers here, couple of tips I'd like to add -
often using any of the lassoo's you will be zoomed in, first be sure you are in "full screen mode" when you need to move to a part which is now off the screen, just hold down the space bar and you will temporarily get the hand tool which allow you to move your picture and carry on with the lassoo you are using.
Remember too, when you use the magnetic lassoo you can keep adding clicks, do this when you get to a part which has less definition, and I also find it much easier to use with caps lock on, its much easier that way to see the "hot spot" which is detecting the edge.
Hope this helps!
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