How to quickly recognize G-Perms?

[fleeting_penguin]

What is the best way to recognize which G-Perm to use quickly? I take a few seconds to think in my head about where the corners and edges go, and seeing G-perms come up 2/9 of the time I figure I should fix this deficiency.

 

[Jason Baum]

Every G perm has a side that has two corners of the same color, and a 1x2 block. Find the matching corners and put them on the left, then see where your 1x2 block is. That's by far the best way to recognize the G perms.

 

[Pedro]

yeah, what Jason said

 

[DanHarris]

I use a similar trick to the one Jason described, although he didn't describe it in full I think. Rather than finding the corners, I find the 1x2 block and put them on the right. So this reduced it from 4 cases to 2 cases, by identifying whether then block is on B or F. Then I look at the other stickers of the block, which aren't the same colour, and I see if they are opposite colours, or adjacent colours, and this reduces the cases from 2 to a possible 1.

*note* I don't actually do this, but it's how I started. Now I can, in the famous words of Mr Vandenbergh, "just see it".

 

[Theromy]

I do exactly what Jason does, I can recognise which one I need to do as soon as I see where the 2x1 block is.

 

[Ron]

Hi guys,

See below how I learned to recognize PLL cases. Now it is fully automated.

For PLL I first checked which of the corner cases I have. You can find that out from any angle of the cube:
1) if stickers at FUL and FUR are the same, and/or RUF and RUB, then you know:
a) whether you have all corners correct
b) or where the two correct corners are (resp. F or R side)
2) else, if stickers FUL and RUB are the same, then the two correct corners are opposite of the side where FUR/FUL or RUF/RUB have opposite colors
3) else, you have a diagonal swap

G perms are cases 1b) and 2)
Now for all my starting positions, the two correct corners should be on F face.
Look at the edge stickers FU and LU.
Combination 1: LU is opposite of LUF and FU is opposite of FUL: Gd
Combination 2: LU is opposite of LUF and FU is not opposite of FUL: Ga
Combination 3: LU is not opposite of LUF and FU is opposite of FUL: Gb
Combination 4: LU is not opposite of LUF and FU is not opposite of FUL: Gc
Now if you want to recognize from all angles, it is just a matter of deduction, similar to the above rules.
But I would start by using the combinations 1/2/3/4.

Have fun,

Ron

 

[ExoCorsair]

Ron, do you use the G permutations that you listed at speedcubing.com?

 

[Ron]

Hi,

Ron, do you use the G permutations that you listed at speedcubing.com?

I use the ones on http://www.speedcubing.com/final_layer_permutation.html only for one-handed, 4x4 and 5x5.

I use the ones on http://www.speedsolving.com/showthread.php?t=708 for 3x3.

Have fun,

Ron