[Help Thread] Void Cube Discussion

[xkheldar]

I'm just wondering, when I do the void cube, I get parity. So what should I do to fix it? 4x4 parity algs?

 

[cookingfat]

Swap UF with UR (changes 4 centres):
R F' L2 F2 U' D R' F B' D' F2 D F'

Swap UF with UR (changes 6 centres):
U2 R2 D R' L B' R2 F2 U D' R' F' B U

Swap UF with UB (changes 4 centres):
U F' L' B U' R' L2 D L' D' B R L2 U

Swap UF with UB (changes 6 centres):
F L R' B U2 D' F U L' U' L R' D' F' R'

they should work.

 

[TMOY]

For swapping UF and UB, there is also:
U M' U' B2 U M2 U' F2 U M' U' B2 M' F2 M2
If you want to use 4^3 parity algs you first have to find a way to split the middle slice in rwo

 

[Ton]

http://www.speedsolving.com/forum/showthread.php?t=6188&highlight=void+cube&page=3

Tip . try search function

 

[ImNOTnoob]

Simple way: Do u or u'.
Then (re)solve the middle layer.
The pairity should be gone.

 

[Stefan]

I get parity. So what should I do

Properly understand what you're talking about. Parity is not just a buzzword synonym for "bad case", it actually has insightful background/meaning.

 

[rjohnson_8ball]

Although you know it is just like the 4x4 PLL parity problem, I think what Stefan means is if you knew the reason why it happens, then you would probably find a way to fix it.

The reason why it happens is that the void cube can have 2 opposite centers correct but the remaining 4 centers offset by 90 degrees. This 4-cycle causes the PLL parity. (To prove this to yourself, try solving a standard cube, but with the centers on the 2nd layer shifted by 90 degrees -- you will get the PLL parity.)

As said earlier, rotate the 2nd layer by 90 degrees, resolve the 2nd layer against your first layer (without simply moving it back by 90 degrees), then resolve the last layer against those.

 

[TMOY]

At corners first, the "parity case" is simply the case where all four edges are misoriented in the orient middle layer step. Just apply the corresponding algorithm.

 

[Stefan]

Indeed I prefer people understand things rather than blindly follow instructions eagerly provided by people who want to keep them clueless. Especially if there's deeper insight to be gained.

I don't get why you bring up centers here. First of all, the void cube doesn't have any. Plus, it's absolutely unnecessary to invoke them. An inner "slice" move of the void cube is a clean odd permutation of pieces, exactly what's needed.

 

[joey]

At corners first, the "parity case" is simply the case where all four edges are misoriented in the orient middle layer step. Just apply the corresponding algorithm.

uhh.. what?

 

[TMOY]

When applying an inner slice move to a void cube with two edges swapped, not only as Stefan says you perform an odd permutation, but you disorient all four edges of the slice. If you flip them all, you get back to a position which is only a simple 3-cycle away from the solved state.

 

[joey]

aha, okay. I thought you were saying a 4-flip was parity!

 

[rjohnson_8ball]

At corners first, the "parity case" is simply the case where all four edges are misoriented in the orient middle layer step. Just apply the corresponding algorithm.

uhh.. what?

I think TMOY means mispermuted not misoriented. In any event, as we all say, perform a quarter turn slice move (for example, the 2nd layer slice), then permute the edges without undoing that slice move.

As far as an algorithm goes, I generally just wing it. (I resolve the 2nd and 3rd layers after doing the slice).

But if you begin with everything solved except the pair (UF BF) needing to be swapped, then you could do E (U2 R2)*3 (E L2 E' L2), followed by flipping all edges on the 2nd layer. (Note E indicates the slice in direction of D.) I am sure this is not the most efficient way. (I hope Stefan doesn't beat me up for telling you!)

 

[Stefan]

When applying an inner slice move to a void cube with two edges swapped [...] you disorient all four edges of the slice.

Ugh, that very much depends on your definition of oriented/disoriented, and is false in most cases! I can easily define an orientation scheme where no inner slice moves "disorient" any pieces. And I can define one where a 180 degrees turn of a slice disorients all involved pieces. It's also possible to make a move and "disorient" an odd number of edges, though I don't see useful real world applications for it.

 

[TMOY]

My definition of oriented/disoriented is the usual one for CF, where's the problem ?

 

[Stefan]

My definition of oriented/disoriented is the usual one for CF, where's the problem ?

That you didn't say that (and that "the usual one" is unclear).

 

[TMOY]

OK, assume the top and bottom layers are solved. A middle layer edge is correctly oriented if every of its stickers is either on the correct face or on its opposite.
On a regular 3^3 the "correct" face is defined with respect to centers. On a void cube there are no centers, but if you place the top and bottom layers in such a way that the stickers of the same color face each other, the correct face can be defined with respect to them. Is it clearer ?

 

[JTW2007]

Lubing a void cube

I just got a void cube for christmas and was wondering if it's possible to lube, and if so, how and with what?

 

[Pietersmieters]

If you turn a layer +- 45 degrees you will see those small holes , I jus sprayed in it well that's how I did it

 

[joey]

It's just the same as a normal cube.