[Help Thread] FMC Discussion

[Matt S]

Blah made a nice post in this thread about the technique I think you're asking about.

http://www.speedsolving.com/forum/showthread.php?p=241389#post241389

Yeah. That quite nice technique. But, that wasnt' technique i ask.

Thanks Matt. ^_^

Sorry, your first comment made it seem like you wanted to know how to do "premoves" during the block-build, which isn't true of what people normally premoves (Those are applied before the scramble to make pseudo-blocks look like real blocks, like Cride showed). I'm glad you found the link useful anyway.

 

[undick]

I sometimes use premoves when I have an F2L composed of pseudo blocks. For example, if you've completed a 2x2x3 and then you see a nice 1x2x2 which normally forms part of your last layer, you can just complete F2L with that block. If you re-scramble but apply the move you used to place that pseudo block then the block will now belong to the F2L.

Looking at this example from weekly comp #23:
Scramble: L D2 F' L2 B2 R2 D L2 R D2 L2 B' D' F R' F' D'
F2L-1: D' L' B D2 U2 R2 B2 D F2 L2 D' B' U' B

Gives this situation:


It's fine to just complete the LL from here, undoing the pseudo block at the end, but you can make your life easier by applying the premove D2 to get this F2L:

Wow. Nice explanation Cride

What i'm asking about is just like this solution. This is Guus solution at fmc.mustcube last week.

Scramble : U' F R2 F R L U' B2 U D2 B' D B' L2 B' F U F' U F B2 D2 U B U2 B D2 F2 L2 B'

Solution : D' R' B U R U' B2 R' U R' U D2 F2 R U L U' R' U L' U L2 F2 B2 U' R2 L (27 moves)

solve in inverse scramble with premove [D]
F2L+edge frame: L' R2 U B2 F2 L2 U2.F2 D2 U' R U' R B2 U R' U' R (19)
premove correction: D (20)
at dot insert U L U' R U L' U' R', 1 move cancels



Premove D mean D' in normal scramble. 1 pair is premade
And with D' applying in normal scramble, i don't see any potential pair, that just break up 1 Inner Pair (Red-Blue). How do you get this premove? Can you explain?

Thanks.

 

[nlCuber22]

...That's not Guus >_>

 

[Cride5]

Premove D mean D' in normal scramble. 1 pair is premade
And with D' applying in normal scramble, i don't see any potential pair, that just break up 1 Inner Pair (Red-Blue). How do you get this premove? Can you explain?

Thanks.

I guess Guus will be able to explain properly later, but it looks like the premove is being used to correct a pseudoblock in this case.

If you take the inverse scramble: B L2 F2 D2 B' U2 B' U' D2 B2 F' U' F U' F' B L2 B D' B D2 U' B2 U L' R' F' R2 F' U
Then apply the moves for F2L: L' R2 U B2 F2 L2 U2.F2 D2 U' R U' R B2 U R' U' R
... you will see a 1x2x2 block in DFR which is out of alignment by D. Applying the premove D at the beginning of the inverse scramble allows that block to become part of F2L without destroying any of the other pairs. The use of the premove here isn't anything to do with NISS, it just happens that Guus found a nice solution using pseudoblocks on the inverse scramble.

 

[Stini]

The use of the premove here isn't anything to do with NISS

I know I'm nitpicking here, but technically pseudo block corrections are also part of NISS since you can find the premove to fix a pseudo block using the inverse scramble. But I agree that it's useful to think pseudo blocks separate from NISS, it's just simpler that way.

Also to undick: you can't always see the reason for pre-moves from the initial state. Sometimes you might notice for example after building a 2x2x3-block that by using a pre-move, you would get a pair. But you would see this pair only *after* solving the 2x2x3-block.

 

[undick]

Oh, yeah. I see. Premove is very complex. So, i can use premove as far as not destroying any of the other, right? I always use premove only for a fix block or pair. Cride and Stini, thanks very much.

I just got 29 moves on WFC-24. Sub-30 without any premoves. Hehe

 

[guusrs]

The use of the premove here isn't anything to do with NISS

I know I'm nitpicking here, but technically pseudo block corrections are also part of NISS since you can find the premove to fix a pseudo block using the inverse scramble. But I agree that it's useful to think pseudo blocks separate from NISS, it's just simpler that way.

Also to undick: you can't always see the reason for pre-moves from the initial state. Sometimes you might notice for example after building a 2x2x3-block that by using a pre-move, you would get a pair. But you would see this pair only *after* solving the 2x2x3-block.

Conrad, this is me!
And you explained well how I found that premove at that 27-move solve.

But Teemu is right, I wasn't complete at all, I was realy busy at work and then decided to give a quick reply. Conclusion: Some (sequences of) pre-moves are found with NISS, Others pre-moves correct pseudo blocks during a solve.
Most important: Undick seems to understand all this now.

Gus

 

[undick]

Most important: Undick seems to understand all this now.

Gus

:fp. Not at all before i try it. Nice explanation.

 

[Cerberus]

From Cologne Open, my national record, which I don't deserve since I am not quite into fmc and am just going for PLL skip and some nice F2L
But I got a 29 this time.. after finding a brilliant 16 move F2L

Scramble:
B2 F2 R2 U' R2 B2 R2 B2 U F' R2 B' U2 R B D' U2 R B2 U'

Solution
x2 R U' F D L' D2 2x2 block and saving the pair
U B' R' U' F R' F' finishing tripple x-cross now L U L' give you 16 move F2L
L U2 L' U L U2 L' F2L after some tries for better LL =)
y L' U2 L U 2 L F' L' F U2 OLL with PLL skip

 

[mr. giggums]

So I'm thinking of starting FMC. So this is my first FMC solve...

Scramble: B2 D R2 D2 B' D B2 D' U B2 U2 F' L2 U' L' R' U L D2 L' U2 R2 F' L' R'

2x2x2: B R2 B' D L F2
2x2x3: B' R D' R2 D2 B2 D B2 D
EO: R D' R' D
F2L: R2 B' R2 B'
EJF2L: R B' R' B R' B3 R' B' R' B' R2 B2
PLL: R' D B' D F2 D' B' D F2 D2 B2

total of 46

 

[trying-to-speedcube...]

From Cologne Open, my national record, which I don't deserve since I am not quite into fmc and am just going for PLL skip and some nice F2L
But I got a 29 this time.. after finding a brilliant 16 move F2L

Scramble:
B2 F2 R2 U' R2 B2 R2 B2 U F' R2 B' U2 R B D' U2 R B2 U'

Solution
x2 R U' F D L' D2 2x2 block and saving the pair
U B' R' U' F R' F' finishing tripple x-cross now L U L' give you 16 move F2L
L U2 L' U L U2 L' F2L after some tries for better LL =)
y L' U2 L U 2 L F' L' F U2 OLL with PLL skip

R U' R' B2 R' B2
F D' L2 F
D2 F' D F2 D2 F' D' F D F'
L' D L D' L' D2 R D' L D' R' D' R D' R' D

Linear 36-move solution found after 5 minutes; I couldn't find anything nice after that

 

[Cerberus]

I got this F2L after 1 Minute straight forward =) then just searching around for better LLs

 

[Ranzha]

I did this FMC because I saw a potential x-cross. And then ZOMG.

Try this out! FOR SRS!

Scramble:
F2 R2 B2 L2 R2 U' R2 F2 D2 U B2 D' U2 R' F D2 F' D R' F U' R

2x2x2: z2 R U2 R2 U' F [5/5]
2x2x3: x' U2 L y' R' U' R [5/10]
(WAIT! WHAT IS THIS I DON'T EVEN)
Solving the two pairs on the R face: y x' D' L' U L U2 D' F R' F' R D2 U [12/22]
EO: z U2 x R U R' U' x' U2 R U R U' R2 [11/33]
Solving corners R2 D' R2 U2 F2 U L' U' L F2 U2 R' D R [14/47]

I was just liek WHAT?!

 

[Gurplex2]

 

[Meep]

Should move it here lol

 

[Sa967St]

9x9 pop video

I think you meant to put that in this thread.

 

[Gurplex2]

9x9 pop video

I think you meant to put that in this thread.

lolol YEAH
I like how that was my 3rd fastest solve ever... oh well

 

[okayama]

I tried to get sub-30 for Weekly competition 2010-24 after 1-hour, but I couldn't. Here are another solution and a promising start. Could anyone find a way of improving it?

Spoiler

Scramble: F2 D2 F L2 D' R' F2 U L2 R2 D B D2 R' B2 L2 D L
Solution: B' L' B' U R' U2 R2 F' U2 B' U L' F R2 F' L F R2 U' B U R' B' R B2 L' F D2 B' D (30 htm)

(For inverse scramble)

Pre-scramble: U' B L B

1x2x2 block: D' B D2
2x2x3 block: F' L B'
Orient edges: B' R' B R F' + U F
All but 2 twisted corners: R' * D R' U2 R D'
Pre-scramble correction: U' B L B

Insert at *: R' U2 R D R' U2 R D' (leave 4 corners, 11 moves cancel)
Insert at +: F U' B' U F' % U' B U (leave 3 corners)
Insert at %: F R2 F' L' F R2 F' L

First insertion gives a 19 moves frame with 4 corners left, but I couldn't find nice insertions that bring sub-30...

The following start (triple X-cross with 13 moves) also looks nice for me, but I couldn't find a good continuation.

(For inverse scramble)

Pre-scramble: B L B

1x2x2 block: D' B D2
2x2x3 block: F' L B'
Orient edges: B' R' B
F2L minus 1 slot: R' U

Aside from this, I will go to MRCC, Będlewo, Poland next week (June 20 -- 26). Could someone tell me what's the temperature around the area?

 

[Snigel]

First FMC

Hello!

This weeks FMC was my first ever and I write this in order to get some feedback. I haven't been cubing for very long and I don't have such a deep understanding as some people here seem to have. I have learnt Petrus, Heisse (just for a few hours) and a 3-cycle method for BLD. I know full PLL, but not full OLL. i say this just to give you an idea of what I can and can't do. If someone has the time to comment on what I did for this week's FMC, I'd be delighted!

Here is the scramble: R' D U B D' L R B' F' U2 B2 F' U' F R B D' B2 U' D2 R D2 B' D B D' R2 L B L2

And my solution:
2x2: F' B' R' D' B' D2 (6/6)
2x2x3: F . U' R F R2 (5/11)
Extend: U' F2 U2 F' L F2 L2 (7/18)
EO: U2 L (2/20)
EP: F U F' U' (4/24)
Corners: R' D R U' R' D' R U (8/32)

Insert at dot : F' D' F U2 F' D F U2 (cancels four, so 8/40 - 4 = 36)

I know basic block building from Petrus, but since I've only used it for speedcubing before, I still find it pretty hard to find optimal solutions, especially after the 2x2x2 is built (and obviously, my 2x2x2 wasn't the best around either). I wasted even more moves on the extension of the block.

The ending seems better and I also tried to find an insertion, which went pretty well, although that might just have been luck.

My biggest problem, I think, is that it takes me ages to do the practical things. I often screw something up and don't remember how to revert, meaning I have to solve the cube and scramble it again, which takes perhaps a minute. I don't know how long it took me to find this solution, but it was probably a couple of hours.

So, any suggestions where I can improve?

Cheers!

Olle Linge
http://www.snigel.nu

 

[PM 1729]

Its very good for your first attempt.

The block building does not need to be optimal. Try to explore possibilities which have better continuations.

Learn how premoves work (if you don't already know). It will help you a lot.

Finally ,you should practice to reduce the time you take to find a good solution.

All the best!