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So I'm tring to follow a specifications document from https://homes.luddy.indiana.edu/stsher/files/Rubiks_Cube.pdf to model the corner cubelet using meters instead of cm. I'm not sure though if there's something wrong with the document or with my model. I'm pretty sure though that I'm using a sphere with 1.9 meter radius but somehow the 0.8 m and 1.48 m measurements do not add up as the 0.8m goes past the sphere and can't cut the sphere as shown in the specifications document. Please let me know if there's a clearer specifications document somewhere else i can use? The .blend file is uploaded here https://blend-exchange.com/b/0gMby714

enter image description here

Harry McKenzie
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  • There seems to be something wrong with the drawing. If I follow all the measurements the 1.48cm is actually 1.23cm. – Luciano May 17 '22 at 09:16
  • yeah that's what i also noticed. so you also think they made a mistake in their documentation? but still the 0.8 doesn't work out for me. – Harry McKenzie May 17 '22 at 09:28
  • It looks like. If I follow all the measurements except the 1.48cm everything else seems correct, at least in 2D. – Luciano May 17 '22 at 09:31
  • @Luciano You're right, either the 1.48 is wrong or the 2.33, but optically 2.33 seems to be more correct. I made an answer anyway, because as Harry put it he seems to have a problem with the 0.8, in his image he uses it for the complete edge length, which of course can't work. – Gordon Brinkmann May 17 '22 at 10:22

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I'm not sure with what measurements you constructed yours, but when I look at the schematics and try to build this myself, I get more or less the desired result. Maybe the schematics are not proportionally correct, but at least I get something that looks as I expected.

So here are the schematics:

schematics

I'll then create three objects:

  1. A larger cube with edge lengths of 1.90, with his bottom left corner at coordinates (0, 0).
  2. A smaller cube with edge lengths 1.48 and the bottom left at (1.1, 1.1), that's 0.8 off the edge of the larger cube as shown in the schmeatics.
  3. A cylinder with a radius of 1.90 at coordinates (2.85, 2.85).

construction

If I then combine those objects with a Boolean modifier, I get a result that resembles the schematics, it only looks as if the 1.48 are more than the size of the cube in the schematics. However, if these are supposed to be the correct values, it shouldn't matter if it looks exactly like the schematics. There seems to be an error either with the 1.48 being incorrect or the 2.33, the dimensions in the schematics look like 2.33 could be right and 1.48 is wrong, but without having a Rubik's cube and disassembling it I can't tell what is correct. I would have to look at all the other pieces and figure out with which values they work best. A page before that in the document there are schematics for an edge cubelet, there is for example on the left side two heights 1.90 + 0.54 (= 2.44), and on the right side it says 2.43, so I guess there might be some discrepancies elsewhere as well.

result

Gordon Brinkmann
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  • thank you for helping me out. i would really be interested though to know where my mistake is though in the blend file XD – Harry McKenzie May 17 '22 at 10:50
  • @HarryMcKenzie Well, since you have everything constructed upside down somehow it's confusing at first... but the sphere you have used was definitely too small. The schematics say the radius is 1.90, while yours had something like 1.82 before you cut it. – Gordon Brinkmann May 17 '22 at 11:05
  • im fairly sure i used a 1.9m uv sphere. i double checked by adding another 1.9m radius sphere overlapping the cut-out one and i can see that they both have the same overlapping surface. can u try it? – Harry McKenzie May 17 '22 at 11:17
  • @HarryMcKenzie I did try it. The problem is, the origin where you first created the sphere is of course lost after merging it with the cube, but it looks definitely like you created it at the world origin (0, 0, 0). Here is a picture where I laid a circle with radius 1.90 and another with 1.82 over your sphere, and the 1.82 seems to fit much better (or maybe 1.825 at max): comparing the sphere radius – Gordon Brinkmann May 17 '22 at 11:32
  • thank you for showing it to me. hmmmm that is really a bummer coz i was trying to be super careful not to make any mistakes. damn. oh well thank you! – Harry McKenzie May 17 '22 at 11:53
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    @HarryMcKenzie You're welcome :) – Gordon Brinkmann May 17 '22 at 12:07