# 6x6x6 cube with smooth plates on bottom?

Adult, returning to Legoland and the world of LEGO.

I'm interested in building a static 6x6x6 cube that is smooth on all six sides. I can see how to get the top smooth, using an appropriate build up with blocks and plates, and capped with smooth tiles.

The sides are easy, of course, just being the sides of blocks and other pieces.

But what about the bottom? What works for reversing the studs, so that smooth tiles can be used for the final finish on the bottom?

I would like the final build to be rock solid, exactly 6x6x6 -- no movement like a rubik's cube needed at all.

Just interested in best techniques for a smooth bottom, before I order parts for my bigger build. Want to limit pieces to standard blocks, plates, and smooth tiles.

Suggestions, threads to review, links to solutions?

PS: Sorry I couldn't post tags like: "6x6x6 cube tiles smooth"; suggestions welcome.

## 4 Answers

While there could be various approaches building studless the easiest one would be with Tile, Modified 2 x 2 Inverted. These modified tiles have studs on one side, which fit under bricks and plates, and smooth surface on the other side.

Here is a prototype which features equal 6-stud (or 30 modules) long sides. Parts can be changed upon availability, but it gives the idea how high you need to go to reach 6-stud height. Red parts are modified tiles mentioned above.

• Excellent. Simple. 2x2 modified, inverted - who knew? Thanks. Commented Mar 23, 2020 at 12:57
• You could also use five normal-height (blue/yellow) layers, and one flat (cyan) layer; the top smooth layer (green) and bottom smooth layer (red) are also 1/3 height, so 1/3 * 3 = 1 (for certain values of 1/3); rather than building up each smooth layer with two flat layers. Commented Mar 23, 2020 at 13:57
• In case with 5 layers of bricks either top or bottom layer must be made entirely of bricks (as example 6 pcs. of 1x6 bricks), not just the edge, to have a place to attach the tiles to.
– Alex
Commented Mar 23, 2020 at 14:29
• Sure. From bricks.stackexchange.com/a/11131/6174 we know that bricks are 7.9mm wide and 9.6mm high. So 6 bricks wide is 47.4mm. And 6 bricks high is 57.6mm while 5 bricks high is 48mm, much closer to the 47.4mm width. And so it is much more cube-like than the question was asking for. I'm guessing you intuited this and left out the layer since it looked or felt more correct. Even I'm amazed the math worked out so well for my intuition. Commented Mar 23, 2020 at 18:39
• Calculation did only account for individual bricks and not the assembly. There's tiny little space exist between two bricks placed side by side. Bricks are also tiny little bit smaller to allow this gap to exist, so you can place and take them apart. Actually, the same question you've linked has top answer which explains that there is such a thing as LEGO Unit, where 1 Lego Unit is 1.6mm, which is used for getting math right and accounts for that gap. 1x1 Brick will be 5x5x6 ratio/unit/module. So 6-studs are 30 units, 5 bricks are also 30 units.
– Alex
Commented Mar 23, 2020 at 19:08

As mentioned in another answer, there are dedicated pieces for this now.

But... 6x6x6 cube is plenty big enough to have a stud-reversing construction inside, then the bottom can be a simple 6x6 plate with regular smooth tiles.

For example put some of these inside the cube:

• Excellent. Clever. Hidden design, love it. Thanks. Commented Mar 23, 2020 at 12:58

Your question sparked an idea of making a completely symmetrical 6x6x6 cube with the same tile on each face.

This is what I came up with:

The LDCad file is here.

Parts list: 6x-10202, 8x-26604, 8x-30414, 2x-3958

I used only parts available in LDCad version 1.6b

• As far as I know LDCad installation does not include LDraw parts. LDraw parts library is an independent product and is not tied to any of LDCad versions.
– Alex
Commented Mar 26, 2020 at 12:28
• I am new with the tools so thanks for letting me know that LDCad uses a common parts library. With other tools I have used it was important to know the version used to create the assembly. Commented Mar 27, 2020 at 7:21
• Can you please add a picture that shows the red and yellow pieces? Thank you! Commented Apr 2, 2020 at 11:04

I had a whole bunch of pieces that were flat, 2x2 with studs on both sides. They were not actually LEGOs but some knock-off brand - I want to say Tyco? Not sure, it's been a while, but it was 100% compatible. I used them for this sort of thing all the time. It annoyed me that there weren't any official LEGO pieces that served this purpose at the time, but the off-brand ones worked well enough.

• You're right. I remember TYCO having these as a kid. I know for a fact that knock-off maker Ausini has these 2 x 2 plates with inverted studs. it's in their instructions here Commented Mar 23, 2020 at 15:52
• Now that I think about it, this set also had the reverse - square 2x2 pieces with holes on both sides so that you could insert two pieces with stubs facing each other. basically of the female-female adapters if the double-stud piece was male-male. Not really relevant to this question, but another notable lack in the base LEGO pieces at the time. (Not sure if they've added them since?) Commented Mar 23, 2020 at 17:47